Atlas · 1,229 glossary

Oncology glossary A to Z

Over a thousand oncology terms defined in one or two plain sentences: a companion to the OncoGx glossary.

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A

A clinical trial or standard treatment for gallbladder cancer: Joining a trial is a decision like any other: the NHS explains that most trials compare a new treatment with the standard one, that a placebo is used only where no proven treatment exists, and that you can leave at any time without it affecting your care.Open in Atlas Source
A clinical trial or standard treatment in lymphoma: Lymphoma has more trials open to it than almost any other cancer, and in several situations a trial is a reasonable choice beside standard treatment rather than a last resort. Asking early keeps the option open, because many trials require that a particular...Open in Atlas Source
Abdominoperineal resection: Removing the rectum and anus together, leaving a permanent colostomy. Used when a low rectal or anal cancer involves the sphincter.Open in Atlas Source
Abigail Alliance v. von Eschenbach (2007): A 2007 US appeals court ruling that terminally ill patients have no constitutional right to buy unapproved drugs after phase 1, which pushed the access movement toward legislation and eventually the Right to Try Act.Open in Atlas Source
Ablation study and multi-task heads: An ablation removes one component or modality at a time and re-measures performance, which is the only way to know what each part contributes; multi-task heads let one shared backbone serve several outputs.Open in Atlas Source
Abscopal effect: When irradiating one tumour causes untreated tumours elsewhere to shrink, via the immune system.Open in Atlas Source
Absolute versus relative benefit (number needed to treat): A relative benefit says the risk fell by a third; an absolute benefit says how many people out of 100 were actually spared, which depends on how common the bad event was to begin with, and is the number that matters for deciding whether a treatment is worth...Open in Atlas Source
ABVD, BEACOPP and BrECADD (Hodgkin lymphoma regimens): The chemotherapy recipes that cure most Hodgkin lymphoma: ABVD (four drugs, the long-standing standard), the more intensive German BEACOPP, and newer versions that replace bleomycin with brentuximab vedotin (A+AVD) or add nivolumab (N-AVD).Open in Atlas Source
Accelerated approval: FDA approval based on early evidence (like tumour shrinkage) on condition that a confirmatory trial follows.Open in Atlas Source
Accrual and enrolment: How many patients a trial has signed up, and how fast. Slow accrual is the commonest reason trials take years longer than planned or close without an answer; only about 5-8% of adult cancer patients ever join a trial.Open in Atlas Source
Accuracy, macro-F1 and confusion matrices: Accuracy is the share of predictions that were right; macro-F1 averages the F1 score of each class equally, so a model cannot look good by getting only the common cancer types right.Open in Atlas Source
Acid-labile hydrazone (AcBut): The hydrazone linker is acid-sensitive and breaks in the lysosome's low pH. It was used in the calicheamicin ADCs, but is too leaky for most modern designs.Open in Atlas Source
Acinar adenocarcinoma of the prostate: The ordinary type of prostate cancer, more than 95 in every 100 cases. If a report says acinar adenocarcinoma it is saying the cancer is the usual kind, which is the kind every guideline, trial and survival figure for prostate cancer is about.Open in Atlas Source
Actinic keratosis (solar keratosis): sun damage, not cancer: Rough, scaly patches on skin that has had a lot of sun, commonest on the scalp, face, ears, forearms and backs of hands. They are not cancer and are not counted as cancer anywhere in the UK, but they mark skin that has been damaged enough to be worth watchi...Open in Atlas Source
Actionable genomic biomarkers: An actionable alteration is a change in a tumour's DNA that maps directly to an approved or investigational drug, so finding it changes what the patient is offered.Open in Atlas Source
Active surveillance and observation: Deliberately not treating a cancer yet, but checking it regularly with blood tests, scans or biopsies and treating only if it shows signs of progressing. Standard for low-risk prostate cancer, small kidney masses and several other slow conditions.Open in Atlas Source
Acute urinary retention: Suddenly and painfully being unable to pass urine at all: it needs treating the same day.Open in Atlas Source
ADC sequencing: The open question of whether a second ADC works after the first one fails, especially when both carry the same type of payload.Open in Atlas Source
ADCC (antibody-dependent cellular cytotoxicity): In ADCC, an antibody flags a cell, and NK cells recognise the flag and kill it.Open in Atlas Source
Adenocarcinoma: A carcinoma arising from gland-forming cells, the kind that make mucus, milk, digestive juices or hormones. The most common type of breast, lung, colon, prostate, pancreas and stomach cancer.Open in Atlas Source
Adenoma detection rate: The adenoma detection rate is the share of screening colonoscopies in which an endoscopist finds at least one adenoma. It is the best single measure of how good a colonoscopy service is, because the patients of endoscopists who find more polyps go on to get...Open in Atlas Source
Adenoma-carcinoma sequence: The adenoma-carcinoma sequence is the step-by-step route by which a normal bowel lining becomes a polyp and the polyp becomes a cancer, as genetic faults pile up over years. It is why removing polyps prevents cancer, and it was the first human cancer to be...Open in Atlas Source
Adolescent and young adult (AYA) oncology: Cancer in people aged 15-39, about 90,000 US cases a year, with a distinct mix of cancers, slower survival improvement than children or older adults, and specific needs: fertility, education and work, psychosocial support and trial access.Open in Atlas Source
Adrenalectomy: Removing an adrenal gland. Open, complete (R0) removal is the only cure for adrenocortical carcinoma.Open in Atlas Source
After Hodgkin lymphoma: the late effects, and the screening that follows them: Most people treated for Hodgkin lymphoma are cured, and the long follow-up cohorts show that the treatment leaves a raised risk of heart disease, of a second cancer and of an underactive thyroid for decades. Several of those risks have a screening programme...Open in Atlas Source
Age, smoking and inherited predisposition: what the treatment risk is added to: Treatment is rarely the only cause of a second cancer, and in adults it is usually not the main one. Smoking is the clearest example: after chest radiotherapy for Hodgkin lymphoma, the risks from tobacco and from treatment appeared to multiply rather than a...Open in Atlas Source
Ageing tissue and clonal fields: cancer as a disease of old tissue: Sequencing of healthy skin, gullet and blood shows that by middle age they are patchworks of mutant clones, many carrying classic cancer mutations, yet cancer stays rare until old age. The ageing tissue view says the mutations are there early and it is the...Open in Atlas Source
Agonist and antagonist: An agonist switches a receptor on, imitating the natural signal; an antagonist sits in the receptor and blocks it without switching it on. Cancer medicine uses both.Open in Atlas Source
AJCC 8th edition prognostic stage for breast cancer: Since 2018 the American staging system gives breast cancer two stages: the anatomic stage from tumour size, nodes and spread, and a prognostic stage that also counts grade and the three receptors. Because triple-negative cancers are usually grade 3 and rece...Open in Atlas Source
AJCC stage (TNM staging manual): AJCC stage is the stage group (I to IV) assigned from the TNM manual published by the American Joint Committee on Cancer; it is the staging most clinical tables record.Open in Atlas Source
Alcohol-attributable cancer: The share of cancers caused by drinking: about 4% of all new cancers worldwide, roughly 740,000 a year, of which a meaningful fraction come from light and moderate drinking.Open in Atlas Source
Alkylating agents and antimetabolites: The two oldest chemotherapy families: alkylators (cyclophosphamide, temozolomide, melphalan) glue DNA strands together so cells cannot copy them; antimetabolites (5-FU, capecitabine, methotrexate, gemcitabine) are fake building blocks that jam DNA synthesis.Open in Atlas Source
Alkylating agents and therapy-related myeloid neoplasms: Alkylating chemotherapy can damage a blood stem cell in a way that shows up years later as myelodysplastic syndrome or acute myeloid leukaemia. It is uncommon, it depends on the total dose, and the risk falls away after about ten years. Knowing the cumulati...Open in Atlas Source
Allogeneic stem cell transplant (allo-SCT): Replacing a patient's blood system with a donor's: chemotherapy wipes out the marrow, donor stem cells rebuild it, and the donor's immune cells hunt down leftover leukaemia. It is the only cure for adverse-risk or relapsed AML, high-risk ALL, MDS and myelof...Open in Atlas Source
Alpha vs beta emitters: Beta particles (lutetium-177) travel millimetres and are good for bulky disease; alpha particles (actinium-225) travel a few cells' width and kill with far higher energy.Open in Atlas Source
Alpha-fetoprotein (AFP): Alpha-fetoprotein is a protein made by the fetal liver that a substantial share of hepatocellular carcinomas switch back on. It is measured in blood alongside ultrasound for surveillance, for prognosis, and to select patients for ramucirumab, but it also ri...Open in Atlas Source
Alpha/beta ratio: A number for each tissue or tumour that says how much it cares about the size of each radiation dose. Low (around 2 to 3): very sensitive to big fractions, like the spinal cord and prostate cancer. High (around 10): mostly cares about total dose, like most...Open in Atlas Source
AML with myelodysplasia-related gene mutations (AML-MR): Eight genes (ASXL1, BCOR, EZH2, RUNX1, SF3B1, SRSF2, STAG2, U2AF1 and ZRSR2) are almost never mutated in leukaemia that arises out of nowhere but are typical of leukaemia that grew out of a smouldering marrow disorder; finding one on the diagnostic gene pan...Open in Atlas Source
AMNOG (Germany, 2011): Germany's 2011 law under which a new medicine is sold at the company's price from day one but must show, within six months, how much better it is than the existing standard; the verdict then drives a negotiated price that applies nationwide.Open in Atlas Source
Amplification: When a cell carries extra copies of a gene, sometimes 50 or more instead of the normal two, so it makes far too much of that protein. HER2 amplification in breast cancer is the classic example and is what trastuzumab exploits; MET amplification is a common...Open in Atlas Source
Anaemia: A shortage of red blood cells or haemoglobin, causing tiredness and breathlessness. In cancer it comes from the disease itself (marrow infiltration, bleeding, inflammation), from chemotherapy suppressing the marrow, and from some targeted drugs.Open in Atlas Source
Anagen effluvium (chemotherapy hair loss): The sudden shedding that starts two to three weeks after chemotherapy begins, because the drug stops hair follicles mid-growth and the shaft snaps off at the scalp. The follicle itself usually survives, which is why hair almost always comes back.Open in Atlas Source
Analytical databases as a data catalogue (DuckDB, PostgreSQL): DuckDB is an in-process analytical database that queries Parquet files with SQL; PostgreSQL is the standard client-server database; either can hold the metadata spine that joins patients, specimens and assays.Open in Atlas Source
Analytical versus clinical validation: Analytical validation shows a test measures what it claims, reliably; clinical validation shows the measurement actually predicts the patient outcome it is meant to.Open in Atlas Source
Androgen deprivation therapy (ADT): Switching off testosterone, the hormone that feeds prostate cancer, with injections (or tablets) that stop the testicles making it, or by removing them. It has been the backbone of advanced prostate cancer treatment since 1941.Open in Atlas Source
Androgen receptor pathway inhibitor (ARPI): The newer prostate cancer hormone pills (abiraterone, enzalutamide, apalutamide, darolutamide) that block the androgen receptor or the last steps of androgen production, used on top of standard testosterone suppression.Open in Atlas Source
Androgen receptor-positive triple-negative breast cancer: Some triple-negative breast cancers carry the androgen receptor, the protein that prostate cancer runs on. About one in eight ER-negative cancers stain positive, and in trials the prostate drugs bicalutamide and enzalutamide held the disease for a minority...Open in Atlas Source
Aneuploidy and chromosomal instability as the cause of cancer: The oldest theory of cancer, from Theodor Boveri in 1914: tumours arise from cells with the wrong number or arrangement of chromosomes. Peter Duesberg revived it in the 1990s as an alternative to gene mutations. Most solid tumours are indeed aneuploid and c...Open in Atlas Source
Angiogenesis: The growth of new blood vessels. A tumour bigger than a pinhead needs its own blood supply and sends out signals (mainly VEGF) to recruit one; anti-angiogenic drugs cut that supply.Open in Atlas Source
AnnData and h5ad files: AnnData is the Python object, saved as an .h5ad file, that holds an expression matrix together with its per-cell and per-gene annotations; it is the lingua franca of single-cell analysis.Open in Atlas Source
Anomalous pancreaticobiliary junction (pancreaticobiliary maljunction): A birth variation in which the bile duct and pancreatic duct join outside the wall of the bowel, so pancreatic juice flows back up into the bile ducts and gallbladder and irritates their lining for life. It carries a high risk of gallbladder cancer, and rem...Open in Atlas Source
Anthracyclines (doxorubicin, epirubicin): A family of red chemotherapy drugs derived from a soil bacterium that damage cancer DNA. Cornerstones of breast cancer, lymphoma, leukaemia and sarcoma treatment, but they weaken the heart in a dose-dependent way, so there is a lifetime limit.Open in Atlas Source
Anti-EGFR rechallenge: When an EGFR antibody stops working, the resistant cells that caused it fade away once the drug is withdrawn. Rechallenge means giving the same class of drug again later, after a blood test has confirmed those resistant clones have receded, and in small tri...Open in Atlas Source
Anti-VEGF class toxicities (hypertension, proteinuria, bleeding, perforation): The shared side effects of drugs that block blood vessel growth (bevacizumab, ramucirumab and VEGFR kinase inhibitors): high blood pressure, protein leaking into the urine, nosebleeds and more serious bleeding, slow wound healing, and rarely holes in the bo...Open in Atlas Source
Antibody: A Y-shaped protein the immune system makes to grab onto one specific target. Manufactured antibodies are now a cornerstone of cancer treatment, either blocking a protein or delivering a payload to it.Open in Atlas Source
Antigen: Anything an antibody or immune cell can recognise, typically a protein on a cell's surface. In cancer, an antigen is the flag that tells a drug or an immune cell 'this is the cell to attack'.Open in Atlas Source
Antigen escape (antigen loss, lineage switch): When a cancer treated with a therapy aimed at one surface marker (CD19, BCMA, HER2) survives by shedding that marker, so the drug has nothing to grab. About a third of relapses after CD19 CAR-T are antigen-negative.Open in Atlas Source
Antigen escape: how a lymphoma loses the thing the drug was aimed at: Treatments that find a cancer by one marker on its surface can be defeated if the cancer stops showing that marker. It is one of the main reasons an antibody or CAR-T treatment that worked stops working.Open in Atlas Source
Apheresis (leukapheresis): Running a patient's blood through a machine that skims off one type of cell (T cells, or stem cells) and returns the rest; the harvested cells become the raw material for CAR-T or a transplant.Open in Atlas Source
Apoptosis: The cell's built-in self-destruct programme, which tidily dismantles a damaged or unwanted cell without alarming its neighbours. Cancer cells disable it by mutating TP53 or overproducing BCL-2; chemotherapy and radiation work largely by inflicting enough da...Open in Atlas Source
Aquagenic pruritus: Intense itching, prickling or burning of the skin within minutes of contact with water, typically after a shower. It affects a large minority of people with polycythaemia vera and can be the most disabling symptom.Open in Atlas Source
AR-V7 splice variant: A truncated form of the androgen receptor that is permanently switched on and ignores hormone-blocking pills.Open in Atlas Source
Aromatase inhibitor: Pills that stop the body making oestrogen (after the menopause, when it comes from fat and muscle rather than the ovaries), starving hormone receptor-positive breast cancer. Taken for five to ten years after surgery, they halve recurrence.Open in Atlas Source
Array and table formats: HDF5, Zarr, OME-Zarr, Parquet: HDF5 and Zarr store large numerical arrays in chunks (Zarr is the cloud-friendly one, and OME-Zarr its bio-imaging profile for slide tiles); Parquet stores tables column by column for fast analytical queries.Open in Atlas Source
Artificial urinary sphincter: An implanted cuff and pump that keeps the urethra closed until you squeeze the pump to pass urine.Open in Atlas Source
Asbestos: A mineral once used everywhere in building, whose fibres lodge in the lung when they are breathed in and cause cancer decades later. It causes both mesothelioma, the cancer of the lining around the lung, and lung cancer itself, and the two are different dis...Open in Atlas Source
Association for Molecular Pathology v. Myriad Genetics (2013): The 2013 US Supreme Court ruling that human genes as they occur in nature cannot be patented, which ended one company's monopoly on BRCA testing and let hereditary cancer testing become cheap and widely available.Open in Atlas Source
Atavistic theory: cancer as a reversion to an ancient programme: Physicist Paul Davies and astrobiologist Charles Lineweaver proposed in 2011 that cancer is not a new invention by each tumour but the re-awakening of an ancient survival toolkit from the earliest multicellular life, about a billion years old, which is why...Open in Atlas Source
Attention-based multiple-instance learning (ABMIL, CLAM): Attention-based multiple-instance learning gives each tile of a slide a learned weight and sums the weighted tile vectors into one slide vector, so a slide-level label can train the model and the weights show which regions mattered.Open in Atlas Source
Autologous stem cell transplant (ASCT): High-dose chemotherapy (melphalan in myeloma, BEAM in lymphoma) that would permanently destroy the bone marrow, made survivable by giving the patient back their own previously collected stem cells, which engraft in 10-14 days. Standard for fit myeloma patie...Open in Atlas Source
Autoregressive (next-token) modelling: An autoregressive model predicts the next element of a sequence from the ones before it; trained on DNA it learns to continue a genome, which is how Evo 2 was built.Open in Atlas Source

B

B cell: The immune cells that make antibodies. They matter in cancer twice over: as the source of every therapeutic antibody, and as the cells that go wrong in most lymphomas, leukaemias and myeloma.Open in Atlas Source
B-ALL risk groups (NCI criteria, ETV6::RUNX1, hyperdiploidy, hypodiploidy, iAMP21, IKZF1, CNS status): Childhood leukaemia treatment is chosen from a risk table built over fifty years: age and white count at diagnosis (the NCI criteria), the chromosome pattern in the blasts (favourable ETV6::RUNX1 and high hyperdiploidy, unfavourable hypodiploidy, iAMP21, KM...Open in Atlas Source
B-cell, T-cell and NK-cell lymphoma: The first thing a lymphoma report says is which kind of lymphocyte the cancer came from. B cells make antibodies and carry a surface protein called CD20; T and NK cells kill infected cells directly and carry no CD20. That single difference is why B-cell lym...Open in Atlas Source
Backbone, add-on and monotherapy: Trial-design vocabulary: the backbone is the established treatment everyone in the trial receives; the add-on is the new drug tested on top of it; monotherapy means the drug alone. Most modern approvals are add-ons to a backbone.Open in Atlas Source
BAP1 loss: BAP1 is a tumour-suppressor gene that mesothelioma, uveal melanoma and clear-cell kidney cancer lose more often than any other; a lost nuclear stain on the biopsy confirms cancer over a benign look-alike in mesothelioma, marks the metastasis-prone half of e...Open in Atlas Source
Barrett's oesophagus: A change in the lining of the lower oesophagus caused by acid reflux that can, in a minority, progress through dysplasia to adenocarcinoma. It is why Western oesophageal cancer is mostly adenocarcinoma.Open in Atlas Source
Basal-like breast cancer: Basal-like is a breast cancer subtype defined by the genes its cells switch on, which resemble the basal cells lining the milk ducts. About four in five triple-negative cancers are basal-like and most basal-like cancers are triple-negative, but the two labe...Open in Atlas Source
Basket trial: A basket trial tests one drug in patients whose cancers share a mutation or marker, whatever organ the cancer started in; each organ type is a basket, and the trial asks whether the drug works across them.Open in Atlas Source
Basket, umbrella, and platform trials: Trial designs that test one drug across several cancers sharing a mutation (basket, such as NCI-MATCH), several drugs each matched to a biomarker within one cancer (umbrella, such as Lung-MAP), or keep adding and dropping arms over time (platform, such as I...Open in Atlas Source
Batch effects and harmonisation: A batch effect is a difference in the data caused by when, where or how samples were processed rather than by biology; if it lines up with the outcome, a model learns the batch instead of the disease.Open in Atlas Source
Bayesian trial design: A Bayesian trial states what was believed before the trial, updates that belief with each patient's result, and reports the probability that the treatment works, rather than a yes-or-no verdict against a p-value.Open in Atlas Source
BCG-unresponsive: The FDA's definition of early bladder cancer that has failed adequate BCG treatment, the population in which most new bladder drugs are first approved.Open in Atlas Source
BCLC staging: The liver-cancer staging system that combines tumour size, liver function and fitness to recommend treatment: ablation or surgery, transplant, TACE, or drugs.Open in Atlas Source
BCR::ABL1 kinase domain mutations (T315I and others): When a CML drug stops working, the leukaemia has usually changed the shape of the pocket the drug fits into; sequencing the BCR::ABL1 kinase domain names the mutation, and the name tells the doctor which drug still fits: most mutations respond to another se...Open in Atlas Source
Benchmarks, leaderboards and contamination: A benchmark is a fixed dataset and task on which models are compared, and a leaderboard ranks them; both mislead once the test data has been seen in training or the metric no longer tracks the goal.Open in Atlas Source
Benign versus malignant: A benign tumour grows but stays put and does not invade; a malignant tumour invades surrounding tissue and can spread. Only malignant tumours are cancer.Open in Atlas Source
Bethesda category (thyroid cytology): The Bethesda category is a six-step scale, from 'not enough cells' to 'cancer', that pathologists use to report a thyroid needle biopsy.Open in Atlas Source
Biliary drainage routes: ERCP stent, percutaneous (PTC) and EUS-guided: When a gallbladder or bile duct tumour blocks the bile duct, the bile has to be let out. The usual route is a stent placed from inside the bowel at ERCP; if that fails or the block is high in the liver, a tube goes in through the skin (PTC), and a newer opt...Open in Atlas Source
Biliary stent problems: blockage and infection: A biliary stent keeps bile flowing but can block after a few months; the warning signs are jaundice coming back, a high temperature or shivering, and a blocked stent can usually be unblocked or replaced the same way it went in.Open in Atlas Source
Biochemical recurrence (BCR): PSA rising again after surgery or radiation, usually years before anything shows on a scan.Open in Atlas Source
Bioelectric theory of cancer (Levin): Cells hold a voltage across their membranes, and tissues share these voltages as patterns that guide growth and regeneration. Michael Levin proposes that cancer is a breakdown of this pattern: tumour cells are depolarised, and in tadpoles restoring the volt...Open in Atlas Source
Biologically effective dose (BED) and EQD2: A way of converting any radiotherapy schedule into a common currency so that, say, five big doses can be compared with 25 small ones. EQD2 expresses the same thing as the equivalent total dose in 2 Gy fractions.Open in Atlas Source
Biologics Price Competition and Innovation Act 2010: The 2010 US law that created a route for copies of biologic drugs such as trastuzumab and rituximab, while giving the original twelve years of protection from those copies.Open in Atlas Source
Biomarker: Anything measurable in the body or tumour that tells you something useful: what kind of cancer it is, how it is likely to behave, or which drug is likely to work.Open in Atlas Source
Biopsy: Taking a small piece of the suspicious tissue so a pathologist can examine it under the microscope. It is the only way to confirm a cancer diagnosis and to learn its type and markers.Open in Atlas Source
BIOSECURE Act: Proposed US legislation restricting federally funded work with certain Chinese biotech service companies, which would affect where ADCs and sequencing get done.Open in Atlas Source
Biosimilar: A biosimilar is a copy of a biologic drug such as trastuzumab, shown to be as safe and effective as the original once its patent expires, usually at a lower price.Open in Atlas Source
Bipolar androgen therapy (BAT): Deliberately giving large doses of testosterone to men whose prostate cancer has learned to live without it, swinging the level from very high to very low each month. It is the opposite of standard treatment, and about a third of men respond, with about hal...Open in Atlas Source
BLA / NDA / MAA (marketing applications) and PDUFA dates: The formal application to sell a drug: a New Drug Application for small molecules, a Biologics License Application for antibodies and cell therapies (US), or a Marketing Authorisation Application (EU). The PDUFA date is the deadline by which the FDA has pro...Open in Atlas Source
Bladder cancer after cyclophosphamide: Cyclophosphamide is one of the few cancer drugs that has been shown to cause a specific solid cancer, in the bladder, and the risk depends steeply on the total dose given. Blood in the urine years after treatment with it is a reason to be investigated rathe...Open in Atlas Source
Blasts (leukaemic blast cells): Immature blood cells that should mature in the marrow but in acute leukaemia multiply without growing up. The percentage of blasts in the marrow defines the disease: 20% or more is acute leukaemia.Open in Atlas Source
Blinded independent central review (BICR): Having outside radiologists who do not know the treatment assignment re-read every scan in a trial.Open in Atlas Source
Blinded trial: Keeping patients (single-blind) or patients and doctors (double-blind) from knowing who is on which treatment, so that hopes and expectations cannot colour the results.Open in Atlas Source
Blinding (double-blind, open-label, placebo-controlled): Whether patients and doctors know which treatment is being given. Double-blind: neither knows (a placebo hides it). Open-label: both do, unavoidable for surgery or radiotherapy but a source of bias when judging progression and symptoms.Open in Atlas Source
Blood-brain barrier (BBB): The tight seal around brain blood vessels that keeps most drugs out, one of the two main reasons brain cancer is so hard to treat.Open in Atlas Source
Body composition (lean mass, fat mass, visceral fat): What a person's weight is made of: muscle, fat under the skin, fat around the organs. It predicts cancer outcomes far better than weight or BMI, and can be read from routine CT scans.Open in Atlas Source
Body image after breast surgery and reconstruction: It can take a year for scars, swelling and feelings about a changed body to settle after breast surgery; a prosthesis, reconstruction, no reconstruction, specialist bras and talking to someone who has been through it are all ordinary routes, and none is the...Open in Atlas Source
Bone marrow: The soft tissue inside bones where all blood cells are made. Chemotherapy damages it, causing the low blood counts that limit how much treatment a patient can take.Open in Atlas Source
Bone metastases and skeletal-related events: Cancer spread to the bones, most common in prostate, breast, lung, kidney and thyroid cancer and myeloma. It causes pain, fractures and high calcium, and the complications are counted in trials as 'skeletal-related events'.Open in Atlas Source
Bootstrap resampling: Bootstrapping refits a model or recomputes a statistic on many resamples of the data drawn with replacement, and the spread of the results is a confidence interval that needs no formula.Open in Atlas Source
Bowel cancer after abdominal and pelvic radiotherapy: Radiotherapy to the abdomen or pelvis raises the risk of cancer in the bowel that sat in the field, and the risk is confined to the irradiated segment. For adults no country runs an organised colonoscopy programme afterwards, so bleeding or a change in bowe...Open in Atlas Source
Brachytherapy (internal radiotherapy): Radiotherapy from the inside: radioactive seeds or a temporary source are placed in or next to the tumour, so the dose falls off steeply and nearby organs are spared.Open in Atlas Source
BRAF V600E mutation: A single spelling change in the BRAF gene that jams a growth switch permanently on. It is found in half of melanomas and in some colon, thyroid, lung and brain tumours, and is treated with a BRAF pill plus a MEK pill.Open in Atlas Source
Bragg peak: The spot where a proton or carbon-ion beam dumps most of its energy and then stops, so tissue behind the tumour gets almost no dose.Open in Atlas Source
Brain metastases (intracranial disease): Tumour deposits that have travelled to the brain from a cancer elsewhere, ten times more common than cancers that start in the brain, mostly from lung, breast, melanoma and kidney cancer. Because the blood-brain barrier excludes most drugs, whether a medici...Open in Atlas Source
BRCA reversion mutations: A cancer with a broken BRCA gene can repair the break itself under the pressure of PARP inhibitors or platinum: a second mutation restores the reading frame, the DNA-repair machinery switches back on, and both drugs stop working. Reversion mutations show up...Open in Atlas Source
Breakthrough Therapy / Priority Review / Priority Voucher: Breakthrough Therapy, Priority Review and the Priority Voucher are FDA fast lanes for drugs that look substantially better than existing options.Open in Atlas Source
Breast cancer after chest radiotherapy given young: This is the second cancer with a real screening programme attached, and the one most worth asking about by name. A woman who had radiotherapy to breast tissue between the ages of 10 and 35, most often for Hodgkin lymphoma, is eligible in England for annual...Open in Atlas Source
Breast conservation or mastectomy: For most early breast cancers, removing the lump with a rim of healthy tissue and then giving radiotherapy leads to exactly the same chance of being alive in twenty years as removing the whole breast. The choice is about the breast, not about survival.Open in Atlas Source
Breast implant-associated anaplastic large cell lymphoma: A rare lymphoma that grows in the scar capsule around a breast implant, usually years later, and usually shows itself as sudden swelling of the reconstructed breast from fluid around the implant. It is strongly linked to textured implants, and it is almost...Open in Atlas Source
Breast reconstruction: Rebuilding the shape of a breast after a mastectomy, either with an implant or with the woman's own tissue, at the same operation or years later. In England every woman having a mastectomy for breast cancer must be offered it, and must be offered both timin...Open in Atlas Source
Breslow thickness: How deep a melanoma has grown into the skin, in millimetres. The single strongest predictor of whether it will spread.Open in Atlas Source
Bridging therapy: Treatment given to keep a fast-growing cancer in check during the weeks between deciding on CAR-T (or transplant) and actually receiving it, while the cells are being manufactured or a donor found.Open in Atlas Source
British and American lymphoma practice: where they differ, and why: The same trials are read in both countries and reach different conclusions, because the British system asks what a treatment costs for the benefit it gives and the American one asks whether it is better at all. This is a list of the places where a patient's...Open in Atlas Source
Bronchoscopy (EBUS, robotic navigation): Passing a camera down the windpipe into the lungs to biopsy tumours and lymph nodes without surgery.Open in Atlas Source
BTK C481S, PLCG2 and BCL2 G101V resistance mutations: When ibrutinib-type drugs stop working in CLL, the usual reason is a mutation at the exact spot the drug binds (BTK C481S) or just downstream (PLCG2); when venetoclax fails, a BCL2 G101V mutation loosens its grip. Each can be seen in blood months before the...Open in Atlas Source
Bulk RNA sequencing (RNA-seq) and the full transcriptome: Bulk RNA sequencing reads all the messenger RNA in a piece of tumour at once, giving one averaged expression value per gene for the whole sample.Open in Atlas Source
Bystander effect (ADC): When a released payload leaks out of the targeted cell and kills its neighbours, including cells that lack the target.Open in Atlas Source

C

C-index (concordance index), Harrell's and Uno's: The C-index is the fraction of patient pairs in which the model ranked the patient who had the event sooner as higher risk; 0.5 is a coin toss and 1.0 is perfect ranking.Open in Atlas Source
CA 19-9: A sugar molecule shed into the blood by most pancreatic cancers; useful to follow treatment, not to screen.Open in Atlas Source
CA-125: A blood protein that rises in most ovarian cancers; useful for tracking treatment, useless for screening on its own.Open in Atlas Source
Calibration: reliability diagrams and the Brier score: A calibrated model's predicted 30 percent risk really happens about 30 percent of the time; a reliability diagram plots predicted against observed, and the Brier score measures the squared gap.Open in Atlas Source
Calicheamicin: Calicheamicin is an enediyne antibiotic used as an antibody-drug conjugate payload: it binds the minor groove of DNA and cuts both strands at picomolar concentrations, about a thousand times more cytotoxic than conventional chemotherapy. That is why it is o...Open in Atlas Source
Cambridge Prognostic Group (CPG 1 to 5): The five-band risk score the NHS uses for prostate cancer that has not spread. It combines the grade group, the PSA and the T stage into one number from 1 to 5, and NICE writes its treatment advice in those numbers rather than in low, intermediate and high...Open in Atlas Source
Cancer AI vocabulary (CanSim terms map): A hub for the vocabulary of cancer AI: the assays and cohorts models train on, the machine-learning and statistics terms in their papers, the standards their data must follow and the licences that govern reuse.Open in Atlas Source
Cancer cachexia: Severe loss of weight and muscle in advanced cancer that eating more cannot reverse on its own. It affects up to eight in ten patients with advanced disease and contributes to a fifth of cancer deaths.Open in Atlas Source
Cancer Drugs Fund (England): An NHS England fund that pays for promising cancer drugs while more evidence is collected, born in 2010 as a political fix for drugs NICE had refused and rebuilt in 2016 into a time-limited managed access scheme with a fixed budget.Open in Atlas Source
Cancer during pregnancy: About 1 in 1,000 pregnancies is complicated by cancer, most often breast, cervical, lymphoma, melanoma or leukaemia. Most chemotherapy is safe after the first trimester, surgery is safe throughout, and ending the pregnancy does not improve the mother's outc...Open in Atlas Source
Cancer health disparities and equity: Systematic differences in who gets cancer, how early it is found and who survives, driven by race, income, geography, insurance and structural racism rather than biology alone.Open in Atlas Source
Cancer stem cell theory and phenotypic plasticity: The idea that a tumour is organised like a tissue, with a small pool of stem-like cells that renew it and a bulk that cannot, so killing the bulk shrinks the tumour but the stem-like cells regrow it. Proved in leukaemia and real in some solid tumours, but t...Open in Atlas Source
Cancer vaccines and oncolytic viruses: Cancer vaccines teach the immune system to recognise proteins on tumour cells; oncolytic viruses infect and burst cancer cells while raising the alarm to immunity.Open in Atlas Source
Cancer-associated fibroblasts (CAFs): The scaffolding cells that tumours recruit to build scar-like tissue around themselves. They feed the cancer, block drugs and immune cells, and carry the FAP protein that PET scans can now see.Open in Atlas Source
Cancer-related fatigue (tiredness): Fatigue from cancer and its treatment is exhaustion that rest does not fix; for most people it improves after treatment ends, and physical activity, a regular sleep routine, eating well and planning the day around what matters most are the things shown to h...Open in Atlas Source
CAPS: the Cancer of the Pancreas Screening consortium and its surveillance studies (CAPS1 to CAPS5): CAPS is the Johns Hopkins-led programme that has followed people at high inherited risk of pancreatic cancer with yearly endoscopic ultrasound and MRI since the late 1990s, and the consortium whose consensus statements set who should be watched and how. Its...Open in Atlas Source
Carcinoid syndrome and carcinoid heart disease: Flushing, diarrhoea and wheezing caused by hormones (mostly serotonin) released by some neuroendocrine tumours; over years it can scar the heart valves.Open in Atlas Source
Carcinoma: Cancer of the epithelium, the lining tissue that covers surfaces and forms glands. Around 85% of cancers are carcinomas, including breast, lung, colon, prostate and skin cancers.Open in Atlas Source
Carcinoma in situ (CIS): Cancer cells that fill the lining layer where they started but have not broken through the basement membrane into the tissue beneath. They cannot spread yet, so removal is usually curative; it is 'stage 0'.Open in Atlas Source
Cardiotoxicity (LVEF decline, cardiomyopathy): Heart damage from cancer treatment: anthracyclines weaken the heart muscle permanently in a dose-related way, trastuzumab does so reversibly, and some kinase inhibitors raise blood pressure or disturb rhythm. Heart function (LVEF) is monitored by ultrasound...Open in Atlas Source
Carers: what you can do and UK carer support: A carer is anyone giving unpaid help to someone with cancer who could not manage without it; you can come to appointments, keep the notes and the medicine list, watch for the warning signs, tell the team you are the carer, and ask the council for a free car...Open in Atlas Source
Carers: what you can do and UK carer support (bowel cancer): A carer is anyone giving unpaid help to someone with cancer who could not manage without it. You can come to appointments and write down the answers, learn the sepsis, blockage and stoma signs, help with bags and supplies if asked, tell the team you are the...Open in Atlas Source
Carers: what you can do and UK carer support (breast cancer): A carer is anyone giving unpaid help to someone with cancer who could not manage without it; you can come to appointments, keep the medicine list and the 24-hour number, learn the sepsis and immune-reaction signs, tell the team you are the carer, and ask th...Open in Atlas Source
Carers: what you can do and UK carer support (pancreatic cancer): A carer is anyone giving unpaid help to someone with cancer who could not manage without it; you can come to appointments, keep the enzyme dose and the medicine list, learn the sepsis, stent, clot and blocked-bowel signs, tell the team you are the carer, as...Open in Atlas Source
Castration-resistant prostate cancer (CRPC): Prostate cancer that keeps growing even though testosterone has been reduced to castrate levels.Open in Atlas Source
CCGA: the Circulating Cell-free Genome Atlas behind the Galleri methylation test: CCGA is the case-control programme of about 15,000 people that trained and validated the Galleri blood test, which reads methylation patterns on cell-free DNA to say whether a cancer signal is present and where it comes from. Its third sub-study set the fig...Open in Atlas Source
CD20 bispecific antibodies: step-up dosing, fixed duration and what it is like to take one: Bispecific antibodies grab a lymphoma cell with one arm and a T cell with the other. The first doses are deliberately tiny because the first full dose is what causes fever and low blood pressure; after that most people take them as an outpatient.Open in Atlas Source
CDKN2A/B homozygous deletion: Losing both copies of the CDKN2A/B genes on chromosome 9p21 removes the cell's main brake on division; in an IDH-mutant glioma it alone makes the tumour grade 4, in mesothelioma and melanoma it marks aggressive disease, and the neighbouring MTAP gene usuall...Open in Atlas Source
CDMO (contract development and manufacturing organisation): A company that makes drugs for other companies. Most ADCs, biologics, and cell therapies are made by a handful of them.Open in Atlas Source
Cell: The smallest living unit of the body. You are made of roughly 30 trillion of them, and cancer begins when one of them starts dividing when it should not.Open in Atlas Source
Cell composition confound (tumour versus stroma and immune cells): Because a tumour sample is a mix of cancer, stromal and immune cells, a difference between two samples may only reflect a different mix of cells.Open in Atlas Source
Cell cycle: The ordered sequence a cell goes through to copy its DNA and split in two, with checkpoints along the way where it pauses to check for damage. Cancer cells run through the checkpoints.Open in Atlas Source
Cell division: One cell splitting into two identical daughters. Tissues need it for growth and repair; cancer is cell division that no longer stops.Open in Atlas Source
Cell line: A population of cells, usually taken from a tumour decades ago, that keeps dividing indefinitely in the laboratory. The workhorse of cancer research: cheap, fast and infinitely reproducible, but a distant cousin of a real tumour.Open in Atlas Source
Cell lines as a proxy for patients: Cancer cell lines are tumour cells grown indefinitely in the laboratory; they are convenient for drug testing but only imperfectly stand in for a patient's tumour.Open in Atlas Source
Cell membrane: The oily outer skin of a cell. Most drugs and antibodies act at this boundary, either by binding to proteins sticking out of it or by slipping through it.Open in Atlas Source
Cell of origin (GCB vs ABC): Whether a large B-cell lymphoma resembles a germinal-centre B cell or an activated B cell; the activated type does worse and depends on different pathways.Open in Atlas Source
Cell of origin in practice: Hans against expression profiling, and what it changes: Large B-cell lymphoma is split into two types by which normal B cell it most resembles. The split is real and predicts how the disease behaves, but the test most laboratories run is a cheaper approximation of the one that defined it, and today the result ra...Open in Atlas Source
Cell-free DNA (cfDNA): Short pieces of DNA floating in the blood, shed by dying cells all over the body. Most is from normal cells; the small tumour-derived fraction (ctDNA) is what liquid biopsies fish out.Open in Atlas Source
Censoring and events in survival data: A patient is censored when the study ends or they leave before the event (death or progression) happens, so we only know they survived at least that long.Open in Atlas Source
Central venous access (port, PICC line): A long-term line into a large vein near the heart, either a small disc under the skin (port) or a tube from the arm (PICC), so chemotherapy can be given and blood drawn without repeated needle sticks.Open in Atlas Source
Centralisation and high-volume centres: Concentrating complex cancer surgery (oesophagus, pancreas, bladder, liver) and rare cancer care in fewer hospitals that perform each operation often. Hospitals and surgeons with high volumes have fewer deaths and complications, so the Netherlands, Denmark...Open in Atlas Source
Cervical precancer (CIN, HSIL/LSIL): Abnormal cervical cells caused by HPV that can turn into cancer over 10-20 years. Screening finds them; a five-minute procedure removes them.Open in Atlas Source
Checkpoint (two meanings): In cancer the word checkpoint means two unrelated things: a brake on immune cells that tumours press and checkpoint inhibitor drugs release, or a gate inside every dividing cell that stops it copying or splitting damaged DNA.Open in Atlas Source
Chemoprevention (tamoxifen, anastrozole, raloxifene) and ER-negative breast cancer: Tamoxifen and anastrozole taken for five years cut the number of new breast cancers in women at raised risk by a third to a half, and NICE offers them to women at high or moderate risk. But the cancers they prevent are oestrogen-driven ones; in the trials t...Open in Atlas Source
Chemoradiation (chemoradiotherapy, CRT): Radiotherapy given at the same time as chemotherapy, which sensitises the cancer to radiation. It is the curative treatment for cervical, anal, laryngeal and oropharyngeal cancers, stage III lung cancer and glioblastoma, and is given before surgery in oesop...Open in Atlas Source
Chemotherapy: Drugs that kill rapidly dividing cells by damaging their DNA or the machinery of division. Because cancer cells divide fast they are hit hardest, but so are hair, gut lining and bone marrow, which is where the side effects come from.Open in Atlas Source
Child-Pugh and ALBI liver-function scores: Scores for how well the liver still works; in liver cancer they decide whether a patient can tolerate treatment at all.Open in Atlas Source
Child-Pugh score: A score of how well a damaged liver is still working, from five simple measures (bilirubin, albumin, clotting, fluid in the abdomen, confusion). Class A is well compensated, C is failing. Liver cancer trials almost all require class A.Open in Atlas Source
China Drug Administration Law (2019) and expedited pathways: China rewrote its drug law in 2019 and its registration rules in 2020, writing in priority review, conditional approval, breakthrough designation and acceptance of foreign trial data, which turned the world's slowest big regulator into one that approves can...Open in Atlas Source
China Human Genetic Resources rules (2019, 2023): Chinese rules that treat blood, tissue and genetic data from Chinese people as a national resource: foreign organisations cannot collect them, international collaborations need approval or filing, and exporting samples or sequence data needs a permit, which...Open in Atlas Source
China National Reimbursement Drug List negotiation and volume-based procurement: China's two price levers: an annual negotiation, since 2017, in which a new cancer drug wins national reimbursement only by cutting its price, often by half or more, and tenders since 2018 in which generic makers bid for guaranteed hospital volumes, collaps...Open in Atlas Source
Choices made at the time of treatment that change the second cancer risk: Some of this risk is a decision rather than a fate. Where two treatments cure equally well and one carries less late risk, that is a conversation to have before treatment starts. Trials have settled several: a different partner drug in myeloma, a lower cycl...Open in Atlas Source
Cholangitis: infection of a blocked bile duct: Cholangitis is infection in bile that cannot drain past a blockage or a blocked stent; fever or shivering with jaundice or a stent is a same-day emergency because it can turn into sepsis within hours.Open in Atlas Source
Choosing treatment for localised prostate cancer: what each option costs: For prostate cancer found by a PSA test, the choice between watching it, operating and irradiating barely changes the chance of dying of it. It changes a great deal whether you will leak urine and whether you will be able to get an erection.Open in Atlas Source
Chromogranin A: Chromogranin A is a protein released by neuroendocrine cells and measured in blood to follow tumour burden; it is unreliable because acid-reducing drugs and kidney disease also raise it.Open in Atlas Source
Chromoplexy: Instead of collecting damage one mutation at a time, a prostate cancer genome can be scrambled in a single burst: several chromosomes break at once and are stitched back together in a chain, knocking out several cancer genes in one event. It was discovered...Open in Atlas Source
Chromosome: One of the 46 long bundles into which a cell's DNA is packed. Cancer cells often have broken, missing, or extra chromosomes.Open in Atlas Source
Circulating tumour DNA (ctDNA): Circulating tumour DNA (ctDNA) consists of fragments of DNA shed by tumour cells into the blood, detectable with sensitive sequencing.Open in Atlas Source
Circumferential resection margin (rectal cancer): The circumferential resection margin is the side surface of the removed rectum, the plane the surgeon cut along. If cancer cells lie within a millimetre of it, the cancer is much more likely to come back in the pelvis. It is measured on the scan before surg...Open in Atlas Source
Cirrhosis: Permanent scarring of the liver after years of damage from hepatitis B or C, alcohol or fatty liver disease. It is the soil in which most liver cancers grow, and its severity limits which cancer treatments a patient can withstand.Open in Atlas Source
CITATION.cff (Citation File Format): CITATION.cff is a small file in a code repository that says, in a machine-readable way, how to cite the software; GitHub and Zenodo read it to generate citations.Open in Atlas Source
CL2A: CL2A is the deliberately fragile linker in Trodelvy: it releases SN-38 in the acidic tumour environment as well as inside cells, feeding the bystander effect.Open in Atlas Source
Classical versus basal-like (squamous) subtypes of pancreatic cancer, and GATA6: Gene expression divides pancreatic ductal adenocarcinoma into two main types: classical, the commoner, which keeps its pancreatic identity and responds better to chemotherapy, and basal-like or squamous, which has lost it and carries a worse outlook. One ge...Open in Atlas Source
Claudin-low breast cancer: Claudin-low breast cancers have lost the claudin proteins that hold epithelial cells together and have taken on the features of migrating, stem-like cells. Most are triple-negative and respond to chemotherapy less well than basal-like cancers. Newer work tr...Open in Atlas Source
Clinical benefit response (the gemcitabine trial endpoint): Clinical benefit response was the measure invented for the 1997 trial that got gemcitabine approved for pancreatic cancer: a patient counted as benefiting if pain, painkiller use, day-to-day function or weight improved for at least four weeks without any of...Open in Atlas Source
Clinical complete response (cCR): No sign of tumour on examination, endoscopy, and MRI after treatment, without surgery to confirm it. It is the basis of organ-preservation strategies.Open in Atlas Source
Clinical covariates (age, stage, nodes, treatment flags): Clinical covariates are the ordinary facts about a patient, such as age, stage, node count and whether they had chemotherapy or radiotherapy, that any prognostic model must beat or build on.Open in Atlas Source
Clinical equipoise: Equipoise is the honest uncertainty that makes a randomised trial ethical: the medical community does not yet know which arm is better, so no patient is knowingly given the worse option.Open in Atlas Source
Clinical text: EHR notes and pathology reports: Much of what is known about a patient sits in free text, in clinic notes and pathology reports; language models are now used to read it and to pair it with slides.Open in Atlas Source
Clinical trial: A research study that tests a treatment in volunteers under strict rules, to find out whether it is safe and whether it works. Every approved cancer drug went through several.Open in Atlas Source
Clinical Trials Regulation (EU) No 536/2014 and CTIS: The EU rule, in force since January 2022, under which a cancer trial is submitted once through a single portal for all the countries it will run in, with results made public, replacing a 2001 directive that made every country's approval separate.Open in Atlas Source
CLL-IPI (chronic lymphocytic leukaemia prognostic index): CLL-IPI scores five things at diagnosis (TP53 loss or mutation, unmutated IGHV, raised beta-2 microglobulin, advanced stage and age over 65) to predict time to first treatment and survival; TP53 and IGHV are the two that still change which drug is chosen, b...Open in Atlas Source
Clonal evolution and the ecological view of cancer: A tumour is a population of cells that mutate, compete and are selected, exactly as species are, and treatment is one more selective pressure. Peter Nowell proposed this in 1976; it explains why tumours are mixtures of clones, why resistance to almost any s...Open in Atlas Source
Cluster-randomised trial: A cluster-randomised trial randomises whole groups (villages, clinics, hospitals) rather than individual people, which is the only fair way to test something delivered to a community, such as a screening programme.Open in Atlas Source
CNS penetration (brain-penetrant drugs): How well a drug crosses from the blood into the brain, where most cancer drugs are kept out by the blood-brain barrier. Brain-penetrant pills can treat and prevent brain metastases; those that are not leave the brain as a sanctuary where the cancer regrows.Open in Atlas Source
CNS prophylaxis in aggressive B-cell lymphoma, and the evidence against it: Some people with aggressive lymphoma are given extra methotrexate, into the spine or into a vein, to stop the lymphoma reaching the brain. It has been standard for decades, and the best evidence now available suggests it does not work.Open in Atlas Source
Co-amplification and the 17q12 HER2 amplicon: When a cancer copies the HER2 gene many times over, its neighbours on chromosome 17 are copied with it; those co-amplified genes are passengers, not the driver.Open in Atlas Source
Coeliac plexus block for pancreatic cancer pain: An injection that deadens the bundle of nerves behind the pancreas, done through the back under X-ray or ultrasound guidance or from inside the stomach during an endoscopic ultrasound; NICE suggests considering it when pancreatic pain is not controlled, opi...Open in Atlas Source
Colectomy: Removing the part of the colon containing the cancer along with its blood supply and lymph nodes, then joining the ends.Open in Atlas Source
Colibactin: Colibactin is a DNA-damaging chemical made by some strains of gut bacteria. It leaves a recognisable pattern of mutations in bowel cancers, that pattern is commoner in people diagnosed young, and it is the strongest current lead on why bowel cancer is risin...Open in Atlas Source
Colonoscopy: Examining the whole large bowel with a flexible camera; polyps found on the way are removed (polypectomy), which prevents most bowel cancers.Open in Atlas Source
Colorectal cancer drugs in England: what NICE has recommended: Which bowel cancer drugs the NHS in England funds, and which it does not. Every reference number below was checked on the NICE website in September 2026.Open in Atlas Source
Colorectal cancer trials open today (registry snapshot): Every phase 2 or 3 interventional trial that was recruiting, about to open or still running for colorectal, colon or rectal cancer on ClinicalTrials.gov in September 2026, with the hospitals in the United Kingdom that take part named where the registry list...Open in Atlas Source
Colorectal cancer: the failed and stopped programmes, and why: The list of treatments that looked right and did not work: EGFR antibodies after surgery, heated chemotherapy washes of the abdomen, immunotherapy in ordinary bowel cancer, and treating a positive blood test before a scan shows anything.Open in Atlas Source
Combined positive score (CPS): A PD-L1 score that counts stained tumour cells and immune cells together.Open in Atlas Source
Companion diagnostic: A companion diagnostic is a test the FDA requires before a particular drug can be prescribed.Open in Atlas Source
COMPASS: real-time sequencing of advanced pancreatic cancer for treatment selection: COMPASS was the Canadian study that took a fresh biopsy from people about to start chemotherapy for advanced pancreatic cancer, sequenced the whole genome and RNA within the time of a treatment decision, and showed that the basal-like subtype predicts poor...Open in Atlas Source
Complete response: All detectable signs of the tumour have vanished on scans and examination after treatment. The best result a trial can record for an individual patient, though microscopic disease may remain.Open in Atlas Source
Complete response (CR) and partial response (PR): A complete response means every measurable trace of the cancer has disappeared on scans or in the marrow; a partial response means it has shrunk by at least 30% (RECIST) but is still there. Neither is the same as cure: microscopic disease can remain.Open in Atlas Source
Complete response letter (CRL): The FDA's formal 'not yet' to a drug application, listing what must be fixed before approval: more data, a different trial population, or manufacturing problems. Not the same as 'complete response' to treatment.Open in Atlas Source
Conditional marketing authorisation (EU): The European (and Chinese) counterpart of accelerated approval: a drug for an unmet need is authorised on less complete data with specific obligations to deliver confirmatory results, renewed yearly until converted to standard approval.Open in Atlas Source
Conditioning regimen (myeloablative, reduced-intensity): The chemotherapy (with or without whole-body radiation) given in the days before a stem cell transplant to destroy the diseased marrow and, for donor transplants, suppress the patient's immune system so the graft is not rejected.Open in Atlas Source
Confidence interval: The range of values consistent with the trial's data, usually given at 95%. A hazard ratio of 0.70 with an interval of 0.55 to 0.89 means the true effect probably lies somewhere in that range; if the range crossed 1.0 the result would not be statistically s...Open in Atlas Source
Confirmatory trial: The randomised trial a company must run after an accelerated approval to prove the drug really helps patients live longer or better. If it fails or never finishes, the approval is supposed to be withdrawn.Open in Atlas Source
Conformal prediction: Conformal prediction wraps any model so that, instead of one answer, it returns a set or interval guaranteed to contain the truth a chosen fraction of the time (say 90 percent), assuming new patients resemble the calibration patients.Open in Atlas Source
Consensus molecular subtypes (CMS1-4): The consensus molecular subtypes are four gene-expression groups of bowel cancer: immune (CMS1), canonical (CMS2), metabolic (CMS3), and mesenchymal (CMS4), with different prognoses.Open in Atlas Source
Consolidation therapy: Treatment given after a good response to kill the cancer cells that are presumably left but cannot be seen, to make the remission last. Durvalumab after chemoradiation for lung cancer is the best-known example.Open in Atlas Source
Contrastive learning (InfoNCE): Contrastive learning trains a model to pull matching pairs (two views of one slide, or one patient's RNA and protein) close together in embedding space and push non-matching pairs apart.Open in Atlas Source
Control arm and comparator (investigator's choice): The group in a randomised trial that gets the existing standard treatment, against which the new drug is judged. Whether the control is the true current standard, an outdated one, or a menu of options chosen by each doctor ('investigator's choice') changes...Open in Atlas Source
Controlled-access genomic data (dbGaP, EGA): Controlled-access data can identify a person (raw sequence reads, germline variants), so it is held in archives like dbGaP and EGA and released only to approved researchers under an agreement.Open in Atlas Source
Conversion therapy in bowel cancer: Conversion therapy means giving drugs to shrink secondary tumours that cannot be operated on at first, in the hope that they become small enough to remove. It is a different goal from simply controlling the disease: the treatment is chosen for how hard it s...Open in Atlas Source
Copy number alteration (CNA): A copy number alteration is a stretch of DNA that a tumour has gained extra copies of or lost, from a single gene to a whole chromosome arm.Open in Atlas Source
Cording (axillary web syndrome): Tight bands of scar tissue that appear in the armpit in the weeks after lymph node surgery and can run down the arm to the elbow, wrist or thumb. They feel like guitar strings under the skin, they hurt and limit movement, and they usually settle within a fe...Open in Atlas Source
Core needle biopsy and fine-needle aspiration (FNA): Taking a sliver of tissue (core) or a few cells (fine-needle aspiration) through a needle guided by ultrasound, CT or MRI, to diagnose the cancer and test its markers without surgery.Open in Atlas Source
Counting the people who live after cancer, and why the number is not a detail: The United States counts its cancer survivors each year and publishes the figure: 18.6 million in May 2025, projected to reach 22.4 million by 2035. Europe cannot produce an equivalent number, and that is a service-planning problem rather than a statistical...Open in Atlas Source
CpG island methylator phenotype (CIMP): Some bowel cancers switch off large numbers of genes at once by chemically tagging their control regions rather than by mutating them. That state travels with BRAF mutation, with the serrated route to cancer and with the accidental loss of DNA proofreading,...Open in Atlas Source
Creams, light and cold for basal cell carcinoma: For a thin basal cell carcinoma there are four treatments that avoid an operation: two creams, a light treatment and freezing. All of them cure fewer people than surgery does, and all of them leave a better-looking face. The trials that measured the differe...Open in Atlas Source
Cribriform growth pattern in prostate cancer: A sieve-like growth pattern inside prostate cancer, named for the holes punched through a sheet of tumour cells. It is the worst-behaving form of Gleason pattern 4, and finding it on a biopsy is a reason to treat rather than to watch.Open in Atlas Source
Cross-resistance: When a cancer that has become resistant to one drug is also resistant to another it has never seen, because the two share a mechanism. It is the central worry in deciding the order (sequencing) of similar drugs.Open in Atlas Source
Cross-validation and stratified k-fold: Cross-validation splits the data into k folds, trains on k minus one and tests on the last, rotating so every sample is tested once; stratified folds keep the class balance the same in each fold.Open in Atlas Source
Crossover in trials: When patients in a trial's control arm are allowed to switch to the experimental drug after their cancer progresses. It is fair to patients but blurs the survival comparison, because the control group has now had the drug too.Open in Atlas Source
Cryoablation: Destroying a tumour by freezing it with a needle that reaches minus 40°C or below; the ice ball is visible on CT, so the treated zone can be watched forming.Open in Atlas Source
CTCAE toxicity grading (grade 3-4 adverse events): The standard 1-to-5 scale doctors use to grade every side effect in a trial: 1 mild, 2 moderate, 3 severe or needing hospital care, 4 life-threatening, 5 death. 'Grade 3-4 events in 40% of patients' is the usual headline safety figure.Open in Atlas Source
Curative intent vs palliative intent: Whether the goal of treatment is to eliminate the cancer for good (curative) or to control it, relieve symptoms and extend life when cure is not possible (palliative). The intent, not the drug, defines the word: the same chemotherapy can be either.Open in Atlas Source
Cure is not enough: when late effects stopped being an afterthought: Children started surviving cancer in the 1960s, and within a decade the doctors who had cured them began writing down what the cure had cost. The phrase that stuck, from a 1975 paper by Giulio D'Angio, is that cure is not enough.Open in Atlas Source
Curettage and cautery: Scraping a small, low-risk skin cancer away with a spoon-shaped blade under local anaesthetic and then sealing the surface with heat, usually repeated two or three times in the same sitting. It leaves no stitches and a round pale scar, and unlike an excisio...Open in Atlas Source
Cystic duct margin: The cut end of the short duct that joined the gallbladder to the main bile duct, examined by the pathologist after a gallbladder is removed. If cancer cells reach this edge, part of the main bile duct usually has to be removed at a second operation; if it i...Open in Atlas Source
Cytogenetics and karyotype: Looking at a cancer's chromosomes under the microscope to find missing, extra, broken or swapped pieces. It has been the main risk-sorting tool in leukaemia, myeloma and lymphoma for decades.Open in Atlas Source
Cytokine: Small proteins immune cells use to talk to each other: alarms, recruitment calls, growth orders and stand-down signals. Some are cancer drugs, and a flood of them is the danger of certain immunotherapies.Open in Atlas Source
Cytokine release syndrome (CRS): A flood of inflammatory signals when immune cells are activated en masse, causing fever, low blood pressure, and sometimes organ failure.Open in Atlas Source
Cytokine release syndrome and ICANS: grading and management: When engineered T cells or a bispecific antibody switch on, the immune system can overshoot. The first sign is a fever, and the treatment is a drug that blocks the main signal, given early. A smaller number of people become confused or drowsy, which is grad...Open in Atlas Source
Cytopenias and myelosuppression: The umbrella term for low blood counts of any kind (white cells, red cells, platelets) when treatment suppresses the bone marrow. Most chemotherapy causes it temporarily; radioligands, CAR-T and some pills cause longer-lasting versions.Open in Atlas Source
Cytoreductive surgery: Cytoreductive surgery is an operation that strips every visible tumour deposit from the lining of the abdomen and from the organs it coats, often taking many hours. In bowel cancer that has spread only to that lining, it is the part of treatment that does t...Open in Atlas Source

D

Data leakage in model evaluation: Leakage is when information from the test data reaches the model during training, through a scaler fitted on all samples, a patient split across folds or a benchmark that appeared in the pretraining set, making the model look better than it is.Open in Atlas Source
Data maturity (immature vs mature survival data): Survival results are 'immature' when too few patients have died (or progressed) for the comparison to be reliable, so medians are 'not reached' and confidence intervals are wide. Mature data come with time and events; early positive looks can fade or streng...Open in Atlas Source
Data monitoring committee (DSMB, IDMC): A data monitoring committee is a small group of independent doctors and statisticians who see the unblinded results while a trial is running and tell the sponsor to stop, change or continue, so that neither patients nor the sponsor are exposed to what the d...Open in Atlas Source
Data use agreements and consent for research use: A data use agreement is the contract a researcher signs to receive controlled data, promising to protect it and use it only as the participants consented.Open in Atlas Source
De-escalation, escalation and response-adapted therapy: Giving less treatment to patients who are doing well and more to those who are not, using a marker such as scan response, ctDNA or MRD to decide. The aim is to cure the same number of people with less harm.Open in Atlas Source
Deauville five-point scale: A 1-to-5 score for how bright a lymphoma looks on PET compared with the liver; 1-3 is considered a complete metabolic response.Open in Atlas Source
Deauville score and PET-adapted therapy: A 1-to-5 scale for how brightly a lymphoma lights up on a PET scan, compared with the liver and the middle of the chest. Scores of 1-3 after two cycles mean the treatment is working and allow it to be shortened; 4-5 means intensify.Open in Atlas Source
Debulking (cytoreductive surgery): Surgery that removes as much tumour as possible when it cannot all be removed cleanly; leaving nothing visible behind is what matters.Open in Atlas Source
Decentralised trial: A decentralised trial brings the trial to the patient: consent by video, drug delivered to the home, blood drawn at a local clinic, symptoms reported on a phone, so people far from a cancer centre can take part without travelling to it every few weeks.Open in Atlas Source
Declaration of Helsinki: The medical profession's own ethics code for research on people, adopted in 1964 and revised most recently in 2024, which every cancer trial protocol cites: informed consent, independent ethics review, the welfare of the participant above the interests of s...Open in Atlas Source
Deep inspiration breath-hold (DIBH): Taking and holding a deep breath during each radiation beam. For left-sided breast cancer it pulls the heart away from the chest wall and cuts heart dose by about half.Open in Atlas Source
Deep mass-spectrometry proteome (CPTAC): Mass spectrometry weighs fragments of every protein in a sample to identify and quantify thousands of proteins and their phosphorylation sites, the closest measurement to what a cell is actually doing.Open in Atlas Source
del(17p) / TP53 aberration in CLL: A del(17p) deletion or TP53 mutation means loss or damage of the p53 safety gene in CLL. These patients should never get chemotherapy; they need BTK inhibitors or venetoclax, usually continuously.Open in Atlas Source
del(5q) (5q- syndrome and lenalidomide response): Losing a piece of the long arm of chromosome 5 causes a distinctive low-risk myelodysplastic syndrome, typically an older woman with severe anaemia and a normal or high platelet count; it is the one MDS with a drug matched to its genetics, lenalidomide, whi...Open in Atlas Source
Deletion: When a piece of DNA is missing, from a few letters to an entire gene. Deleting a tumour suppressor gene removes one of the cell's brakes.Open in Atlas Source
Depth of invasion (DOI): Depth of invasion is how far down a cancer has grown from the surface it started on, measured in millimetres on the pathology slide; in mouth cancer it now sets the T stage and a depth over 4 mm means the neck nodes are treated even when they look clean, an...Open in Atlas Source
Desmoplasia (tumour stroma): The dense scar-like tissue that makes up most of a pancreatic tumour, walling off cancer cells from drugs and immune cells.Open in Atlas Source
DETECT-A: a blood test plus PET-CT to screen 10,006 women with no symptoms: DETECT-A was the first prospective study to give a multi-cancer blood test to people with no symptoms and act on the result: 10,006 women had the test, positives were confirmed by PET-CT, and 26 cancers were found by the blood test, with about 1% of women s...Open in Atlas Source
Dietary pattern scores (Mediterranean, HEI, AHEI, DASH, WCRF/AICR): Scores that grade a whole diet against a healthy pattern instead of counting single foods. They predict cancer risk and survival better than any individual nutrient.Open in Atlas Source
Differentiation: How closely a cancer cell still resembles the mature, specialised tissue it came from. Well-differentiated tumours look like their parent tissue and tend to behave better; poorly differentiated ones look primitive and grow faster.Open in Atlas Source
Differentiation syndrome: When a targeted drug makes leukaemia cells mature all at once, causing fever, fluid in the lungs, and weight gain. Treatable with steroids if caught early.Open in Atlas Source
Digital pathology and whole-slide images (WSI): Digital pathology scans glass slides into gigapixel images that can be viewed, shared and analysed by software, which is what makes AI on pathology possible.Open in Atlas Source
DIPSS, DIPSS-plus and MIPSS70 (myelofibrosis risk scores): Myelofibrosis risk scores decide the biggest question in the disease, whether to go for a stem-cell transplant: DIPSS uses age, blood counts, blasts and symptoms, DIPSS-plus adds chromosomes, transfusions and platelets, and MIPSS70 adds the mutations that m...Open in Atlas Source
Disease volume (CHAARTED high-volume versus low-volume) and LATITUDE risk: In newly metastatic hormone-sensitive prostate cancer the treatment plan starts with a count: four or more bone metastases with at least one outside the spine and pelvis, or any spread to liver or lung, is high-volume disease (CHAARTED), and high-volume men...Open in Atlas Source
Disease-specific staging and risk systems (FIGO, Ann Arbor, IPI, R-ISS, ELN, IMDC): Beyond the generic TNM system, gynaecological cancers (FIGO), lymphoma (Ann Arbor, IPI), myeloma (R-ISS), AML (ELN), kidney cancer (IMDC), neuroblastoma (INRG) and CLL (Rai, Binet) each have their own system that combines stage, blood tests, genetics and fi...Open in Atlas Source
Disseminated tumour cells (DTCs): Single cancer cells that have already spread to distant organs, often found in bone marrow years before any metastasis appears.Open in Atlas Source
Distal pancreatectomy (removal of the body and tail of the pancreas, usually with the spleen): Distal pancreatectomy removes the body and tail of the pancreas, the part to the left of the main vessels, usually with the spleen when the cause is cancer. The bile duct and duodenum are left alone, so there is no Whipple-type reconstruction; keyhole and r...Open in Atlas Source
DM1: DM1 is the maytansine-derived payload in Kadcyla: a tubulin blocker held by a non-cleavable linker, so it stays in the cell it entered.Open in Atlas Source
DM4: DM4 is a maytansinoid payload released in a form that can cross membranes, giving mirvetuximab soravtansine a bystander effect that DM1 lacks.Open in Atlas Source
DNA: The long molecule that stores the instructions for building and running a cell, written in a four-letter chemical alphabet. Cancer is fundamentally a disease of damaged DNA.Open in Atlas Source
DNA alkylator payloads: DNA alkylator payloads chemically damage DNA regardless of whether the cell is dividing, and are aimed at slow-growing and resistant tumours.Open in Atlas Source
DNA cleaver payloads (enediynes): DNA cleaver payloads are natural products that cut both strands of DNA. They are used in the two oldest approved ADCs, both for leukaemias.Open in Atlas Source
DNA crosslinker payloads (PBD dimers): PBD dimers (tesirine, talirine) are DNA crosslinkers that kill at picomolar concentrations, so ADCs need a drug-to-antibody ratio of only about two. Fluid retention and skin and liver toxicity have ended most programmes; loncastuximab tesirine is the approv...Open in Atlas Source
DNA methylation arrays and beta values (450k, EPIC): Methylation arrays measure, at hundreds of thousands of CpG sites, the fraction of DNA copies carrying a methyl mark; that fraction, between 0 and 1, is the beta value.Open in Atlas Source
Doing less to the armpit: Over thirty years surgeons went from clearing every lymph node in the armpit, to taking only the first one or two, to leaving even a cancerous node in place, to not operating on the armpit at all in low-risk cases. At each step the cancer outcome stayed the...Open in Atlas Source
Domain shift and domain adaptation (cell line to patient): Domain shift is the mismatch between the data a model was trained on and the data it meets later (cell lines versus tumours, one sequencing platform versus another); domain adaptation is the family of methods that try to bridge it.Open in Atlas Source
Dose: How much of a drug is given, how often, and for how long. Cancer drugs have long been given at the highest dose a patient can stand, and regulators are now pushing for doses chosen for benefit rather than tolerability.Open in Atlas Source
Dose reduction, interruption and discontinuation: The everyday tools for living with side effects: pausing a drug until a problem settles (interruption), restarting at a lower dose (reduction), or stopping it for good (discontinuation). Between 30 and 60% of patients on oral targeted drugs need a reduction...Open in Atlas Source
Dose-dense and metronomic chemotherapy: Two opposite ways of rescheduling the same drugs: dose-dense gives standard doses more often (every two weeks instead of three, supported by growth factors) to deny the tumour recovery time; metronomic gives small doses continuously to attack tumour blood v...Open in Atlas Source
Dose-escalation designs (3+3, BOIN, dose-expansion): How a phase 1 trial climbs from a tiny starting dose to a useful one: the old 3+3 design treats three patients at a time and moves up if none has serious toxicity; newer statistical designs (BOIN, CRM) use all the data to pick doses more accurately with few...Open in Atlas Source
Dose-limiting toxicity (DLT): A side effect in an early trial severe enough (usually grade 3 or worse, or forcing a long treatment pause) that the dose cannot safely go higher. Counting DLTs at each dose level is how phase 1 trials find the maximum tolerated dose.Open in Atlas Source
Dosimetry: Measuring how much radiation dose each organ and tumour actually received from a radioactive drug.Open in Atlas Source
Double-hit / high-grade B-cell lymphoma: Double-hit lymphoma is a large B-cell lymphoma with rearrangements of two oncogenes (MYC plus BCL2 and/or BCL6), which behaves aggressively and often escapes R-CHOP.Open in Atlas Source
Doublet, triplet and quadruplet regimens: Shorthand for how many active drugs are combined: a doublet is two, a triplet three, a quadruplet four. More drugs usually mean more responses and more side effects, and trials test whether the extra drug earns its place.Open in Atlas Source
Downstaging and conversion therapy: Using drugs, radiotherapy or embolisation to shrink a cancer from a stage where curative treatment is impossible to one where it is: for example, shrinking liver metastases until they can be cut out, or liver cancer until it fits transplant criteria.Open in Atlas Source
Downstream and upstream: Position in a signalling chain: upstream proteins send the message, downstream proteins receive it. A mutation downstream of a drug's target can make the drug useless.Open in Atlas Source
Driver and passenger mutations: the refined somatic mutation theory: When whole cancer genomes were read, tumours turned out to carry thousands of mutations, of which only a handful drive growth; the rest are passengers that happened to be in the cell. The refinement made the somatic mutation theory precise and testable, and...Open in Atlas Source
Driver mutation: One of the few mutations in a tumour that actually causes it to grow. Everything else is a passenger along for the ride. Drivers are the mutations drugs are aimed at.Open in Atlas Source
Drug efflux pumps (ABC transporters): Molecular pumps on cancer cells that eject chemotherapy and ADC payloads before they can act.Open in Atlas Source
Drug resistance (primary and acquired): Why cancer drugs stop working: the tumour either never depended on the target or evolves around the block.Open in Atlas Source
Drug response and drug sensitivity (IC50, AUC): Drug sensitivity is how strongly a tumour or cell line is held back by a compound; it is summarised by the concentration that halves growth (IC50) or by the area under the whole dose-response curve.Open in Atlas Source
Drug-response baselines and frameworks: mean-drug floor, LightGBM, DrEval, IMPROVE, DeepTTA: The floor for any drug-response model is predicting each drug's average effect across cell lines; tuned gradient-boosted trees such as LightGBM often tie or beat deep models under honest splits, which is why evaluation frameworks now exist.Open in Atlas Source
Drug-response data splits: leave-cell-line-out, leave-drug-out, leave-tissue-out: How a drug-response dataset is split decides what a model's accuracy means: hold out cell lines to test personalised prediction, hold out drugs to test drug design, hold out tissues to test repurposing; holding out random pairs only tests imputation.Open in Atlas Source
Drug-to-antibody ratio (DAR): The drug-to-antibody ratio (DAR) is how many payload molecules ride on each antibody, typically 2 to 8.Open in Atlas Source
Drugs before or after the operation: Giving the same drugs before surgery rather than after does not change how long a woman lives, but it shrinks the tumour so that more women keep their breast, and it shows whether the drugs worked, which now decides what treatment comes next.Open in Atlas Source
Dual HER2 blockade: Using two HER2 antibodies (trastuzumab and pertuzumab) at once, which works better than one.Open in Atlas Source
Ductal carcinoma in situ (DCIS): Breast cancer cells confined inside the milk ducts, found mostly by mammography as calcifications. It is not life-threatening in itself, but around a third would progress to invasive cancer if left.Open in Atlas Source
Ducts, lobules and the terminal duct lobular unit: The breast is a tree: fifteen to twenty branching duct systems, each ending in a cluster of milk-making sacs called a lobule. Almost every breast cancer starts at the junction between the smallest ducts and their lobule, which is why the two commonest kinds...Open in Atlas Source
Duocarmycin (seco-DUBA): Duocarmycins are a DNA-alkylating payload family that damages DNA directly rather than through cell division, so they work in slow-growing tumours.Open in Atlas Source
Duodenal stenting and gastrojejunostomy for malignant gastric outlet obstruction: A gallbladder tumour can press on the duodenum so food cannot leave the stomach. A metal stent placed by endoscope relieves this within days; a surgical bypass (gastrojejunostomy) takes longer to work but lasts longer, so the choice depends on how long the...Open in Atlas Source
Duration of response: How long a tumour stays shrunk once it has responded to a drug. A response that lasts two years is worth far more than one that lasts two months, so this is reported alongside response rate.Open in Atlas Source
Duration of response (DoR) and disease control rate (DCR): Duration of response measures how long a tumour that shrank stays shrunk before growing again; disease control rate adds patients whose cancer stayed stable to those who responded. Together with response rate they describe a drug's activity in trials withou...Open in Atlas Source
DXd: DXd is the topoisomerase poison inside Enhertu and Dato-DXd: about ten times stronger than SN-38, it spreads to neighbouring cells and leaves the body quickly once released.Open in Atlas Source
Dysphagia (difficulty swallowing): Trouble swallowing, either because a tumour narrows the food pipe or throat, or because radiotherapy and surgery to the head, neck or chest have damaged the muscles and nerves that coordinate swallowing. It affects nutrition, dignity and the risk of food go...Open in Atlas Source
Dysplasia (pre-cancerous change): Abnormal-looking cells in a surface lining that are not yet cancer but are on the way. Finding and removing dysplasia (cervical smears, Barrett's surveillance, colon polyps) is how screening prevents cancer rather than just detecting it early.Open in Atlas Source

E

Early detection: Finding a cancer while it is still small and confined, when it is most often curable. Five-year survival for most cancers is several times higher at stage I than at stage IV, which is why so much effort goes into detecting them sooner.Open in Atlas Source
Eating after a Whipple operation: slow stomach emptying, dumping and bowel changes: After a Whipple operation the stomach can be slow to empty for days or weeks, meals feel full quickly, and pale, oily stools mean enzymes are needed; small frequent meals, enzyme capsules with everything, a dietitian's review and patience over several month...Open in Atlas Source
Eating after gallbladder removal: You can eat a normal healthy diet without a gallbladder; smaller meals help in the first days, and bloating, wind and diarrhoea usually settle within a few weeks.Open in Atlas Source
EGFR C797S: A mutation that stops osimertinib from binding to EGFR; the main on-target way lung cancers escape it.Open in Atlas Source
EGFR exon 19 deletion & L858R: Exon 19 deletion and L858R are the two common EGFR mutations, together ~85% of EGFR-mutant lung cancer, and both respond to EGFR pills.Open in Atlas Source
EGFR exon 20 insertion: A rarer EGFR mutation (~2% of lung cancers) that does not respond to standard EGFR pills and needs its own drugs.Open in Atlas Source
EGFR mutation subtypes (exon 19 deletion, L858R, exon 20 insertion, T790M): Lung cancers with a mutated EGFR gene are treated with EGFR pills, but which pill and how well it works depends on exactly where the mutation is. Exon 19 deletions and L858R are the 'classic' sensitive ones; exon 20 insertions resist most pills; T790M and C...Open in Atlas Source
EGFRvIII: EGFRvIII is a mutant, tumour-only version of the EGFR receptor found in about a third of glioblastomas. It is an ideal-looking target, yet every drug against it has failed so far.Open in Atlas Source
ELN 2022 risk classification: The three-tier system (favourable, intermediate, adverse) that decides how aggressively an adult with AML is treated and whether a transplant is recommended.Open in Atlas Source
Embedding (learned representation): An embedding is a list of numbers a model produces to stand for an input (a tile, a gene, a patient), placed so that similar inputs land near each other.Open in Atlas Source
Emergency presentation (route to diagnosis): An emergency presentation means a cancer was diagnosed after the person arrived as an emergency, through A&E or an urgent admission, rather than through a GP referral or screening. It is the route with the worst survival because the cancer is usually advanc...Open in Atlas Source
Emotional support and helplines (UK): Shock, fear, anger and numbness are normal after a gallbladder cancer diagnosis; your clinical nurse specialist is the first port of call, and Macmillan, Cancer Research UK nurses, Maggie's centres, Marie Curie and AMMF offer free support to patients and fa...Open in Atlas Source
EMR and ESD (endoscopic mucosal resection, endoscopic submucosal dissection): Removing an early cancer from the inside lining of the gut through an endoscope, with no external incision and the organ left in place.Open in Atlas Source
Enabling characteristic: genome instability and mutation: Cancers mutate faster than normal cells because their DNA repair and chromosome segregation are broken. This fuels every other hallmark.Open in Atlas Source
Enabling characteristic: tumour-promoting inflammation: Chronic inflammation supplies growth factors, survival signals, and mutagens that help cancers start and grow.Open in Atlas Source
Endobronchial ultrasound (EBUS-TBNA): A camera with an ultrasound probe on its tip is passed down the windpipe; the ultrasound finds the lymph nodes sitting just outside the airway wall and a needle is passed through the wall to sample them. It is how lung cancer is staged without an operation.Open in Atlas Source
Endocrine resistance: When hormone therapy stops controlling a hormone-driven breast cancer, either quickly (primary) or after years (acquired).Open in Atlas Source
Endocrine therapy and endocrine resistance: Endocrine therapy blocks the hormones that feed some breast and prostate cancers; endocrine resistance is when the cancer learns to grow without them.Open in Atlas Source
Endocrine-therapy-induced alopecia: Gradual thinning at the parting and crown that builds over months on tamoxifen, an aromatase inhibitor or ovarian suppression. It is not the sudden shedding of chemotherapy, it lasts as long as the treatment does, and it is often dismissed because it is mil...Open in Atlas Source
Endometrial cancer molecular classes (POLEmut, MMRd, p53abn, NSMP): Four groups defined by a few tests that predict outcome better than the microscope: POLE-mutated (excellent), mismatch-repair deficient, p53-abnormal (worst), and 'no specific profile'.Open in Atlas Source
Endoscopy (EGD, EUS, ERCP): Looking inside a hollow organ with a camera on a flexible tube, taking biopsies and sometimes treating on the spot.Open in Atlas Source
Endpoint: The specific outcome a trial is designed to measure, fixed in advance: for example how long patients live, or how long before their cancer grows. A trial 'meets its endpoint' when the new treatment beats the comparison on that measure.Open in Atlas Source
Energy balance: The umbrella term researchers use for the combined effect of what you eat, how much you move and how much fat you carry. It is the framework linking diet, exercise and obesity research to cancer.Open in Atlas Source
Enrichment and biomarker-stratified designs: An enrichment design enrols only patients whose tumours carry the marker the drug needs; a stratified design enrols everyone but tests marker-positive and marker-negative patients separately, to learn whether the marker predicts benefit.Open in Atlas Source
Ensembl gene ID: An Ensembl gene ID such as ENSG00000141736 is a stable machine identifier for a gene that survives symbol changes, so pipelines join on it rather than on names.Open in Atlas Source
Enzyme: A protein that speeds up a specific chemical reaction by binding its substrate in an active-site pocket. Kinases, PARP and topoisomerases are enzymes and drug targets, because a small molecule lodged in the active site stops the reaction.Open in Atlas Source
Ependymoma molecular groups (PF-A, PF-B, ZFTA, YAP1, MYCN): Ependymomas are now named by where they arise and their molecular group: posterior fossa group A (young children, hardest to cure, worse still with 1q gain), group B (older patients, mostly cured with surgery and radiotherapy), supratentorial ZFTA-fusion an...Open in Atlas Source
Epigenetic progenitor theory: cancer without a first mutation: The proposal that cancer begins not with a mutation but with a reversible change in how genes are switched on and off in a stem or progenitor cell, which then makes later mutations more likely and more dangerous. It explains cancers with almost no mutations...Open in Atlas Source
Epithelioid vs sarcomatoid (biphasic) mesothelioma: Mesothelioma comes in a slower 'epithelioid' form and an aggressive 'sarcomatoid' form. Chemotherapy works better in the first; immunotherapy helps most in the second.Open in Atlas Source
Epitope: The exact small patch on an antigen that an antibody or T cell actually grips, like the specific spot on a door handle a hand grabs. Two antibodies can bind the same protein at different epitopes.Open in Atlas Source
Epstein-Barr virus (EBV) in cancer: The common glandular-fever virus, carried lifelong by most adults, which in a minority of people drives nasopharyngeal cancer, some stomach cancers and several lymphomas.Open in Atlas Source
Epstein-Barr virus latency programmes, and why they decide which lymphoma: Almost everyone carries Epstein-Barr virus for life without harm. Which lymphoma it can help cause depends on how many of its genes the infected cell is switching on, and that depends on how closely the immune system is watching.Open in Atlas Source
ER and PR negative under 1 percent (the triple-negative threshold, and ER-low): A breast cancer counts as oestrogen receptor negative when fewer than 1 in 100 of its cells stain for the receptor, and the same rule applies to progesterone receptor. Tumours with 1 to 10 percent staining are labelled ER low positive, but they behave like...Open in Atlas Source
Erectile dysfunction after prostate cancer treatment: Not being able to get or keep an erection after treatment, because the nerves, the blood supply or the testosterone have been affected.Open in Atlas Source
Erythrocytosis (primary vs secondary): Too many red cells. In polycythaemia vera the marrow itself is at fault (primary); far more often the cause is something else driving it, such as smoking, low oxygen, sleep apnoea, a kidney tumour or testosterone (secondary).Open in Atlas Source
Erythromelalgia: Burning pain, redness and heat in the hands or feet, brought on by warmth. In polycythaemia vera and essential thrombocythaemia it comes from platelets clumping in tiny vessels and often disappears with low-dose aspirin.Open in Atlas Source
Escalated chemotherapy or ABVD in advanced Hodgkin lymphoma: more cures, more late harm, and what the interim scan changed: Advanced Hodgkin lymphoma can be treated with a gentler combination that fewer people are cured by first time, or a harder one that cures more but leaves more lasting harm. Scanning after two cycles, and the newer escalated regimens, have narrowed the gap b...Open in Atlas Source
ESR1 mutation: A change in the oestrogen receptor gene that lets the cancer grow without oestrogen, so aromatase inhibitors stop working. Found in the blood in about a third of patients after hormone therapy.Open in Atlas Source
Estimands and intercurrent events (ICH E9(R1)): An estimand is a precise statement of what question a trial is answering, including what to do about patients who switch treatment, stop early or start another drug; the ICH E9(R1) framework makes trials write this down before they start.Open in Atlas Source
Ethics review (IRB, research ethics committee): Before a trial can enrol anyone, an independent ethics committee (an IRB in the United States, a research ethics committee in the United Kingdom) reviews the protocol and the consent form to decide whether the risks are justified and the participants are pr...Open in Atlas Source
EU data and market protection (8+2+1): In the EU a new medicine's trial data cannot be relied on by a generic or biosimilar for eight years, the copy cannot be sold for ten, and an eleventh year is added for a valuable new indication; it is the target of the 2023 reform.Open in Atlas Source
EU HTA Regulation (EU) 2021/2282: joint clinical assessments: From January 2025 every new cancer medicine in the EU gets one shared assessment of how well it works compared with existing treatments, done jointly by member states, so that each country's payer no longer repeats the clinical review, though each still dec...Open in Atlas Source
EU pharmaceutical package reform (2023 proposal): The biggest rewrite of EU medicines law in twenty years, proposed in 2023: shorter default protection from generic competition with extensions for launching everywhere in the EU and for meeting unmet needs, faster assessments, and tighter orphan and paediat...Open in Atlas Source
European Health Data Space Regulation (EU) 2025/327: A 2025 EU regulation that gives patients electronic access to their health records across the Union and creates national bodies that can grant researchers, regulators and companies permission to use anonymised or pseudonymised health data, phased in over th...Open in Atlas Source
Event-free / disease-free survival (EFS, DFS, iDFS, RFS): In early-stage cancer: how long patients stay free of recurrence, progression, or death.Open in Atlas Source
Exatecan (and derivatives): Exatecan is a camptothecin that blocks topoisomerase I; it was too toxic to use as a free chemotherapy, but attached to an antibody that toxicity becomes useful, and it is the parent of deruxtecan and most next-generation ADC payloads. The family shares res...Open in Atlas Source
Exceptional responder: An exceptional responder is a patient whose cancer shrinks or stays controlled far longer than expected on a treatment that helps few people. The US National Cancer Institute defined the term for a study that sequenced such patients' tumours to learn why, a...Open in Atlas Source
Expanded access (compassionate use): The regulated way a seriously ill patient who cannot join a trial can get an unapproved drug: the doctor asks the company, the company agrees, and the regulator reviews the request, usually within days for a single patient.Open in Atlas Source
Extended RAS testing: Extended RAS testing looks for mutations across KRAS and NRAS, not just the one spot that was tested first. It decides who can have an EGFR antibody: the drugs work only when every one of those spots is normal, and testing the wider set moved about one pati...Open in Atlas Source
Extent of resection (RANO resect classes): How much of a brain tumour the surgeon removes, measured on an MRI scan soon after the operation. In glioblastoma, the less tumour left behind, the longer patients tend to live, provided the surgery does not cause new disability.Open in Atlas Source
External and synthetic control arms: Instead of randomising patients to a control group, comparing a single-arm trial against patients treated in the past or recorded in registries, matched by propensity scores. Regulators accepted this for eflornithine in neuroblastoma and other rare cancers,...Open in Atlas Source
External validation: External validation tests a model on patients from a different hospital, country or platform than it was trained on; it is the only evidence that a result travels.Open in Atlas Source
Extranodal extension (ENE): Extranodal extension means cancer in a lymph node has burst through the node's capsule into the surrounding fat; in head and neck cancer it is the single finding after surgery that most often turns radiotherapy into chemoradiotherapy, and in HPV-negative di...Open in Atlas Source
Extraprostatic extension and seminal vesicle invasion: Whether the cancer has grown out through the wall of the prostate (pT3a) or into the seminal vesicles behind it (pT3b). Both move the stage to T3, both make recurrence more likely, and after surgery both are read alongside whether the cancer reached the cut...Open in Atlas Source
Eyebrow and eyelash loss (madarosis): Eyebrows and eyelashes usually fall later than scalp hair and come back later, and their absence is felt more than people expect, because they frame the face and keep dust and sweat out of the eyes.Open in Atlas Source

F

Faecal immunochemical test (FIT): A stool test for hidden blood, done at home every year. Positive results are followed by colonoscopy.Open in Atlas Source
Faecal occult blood test (guaiac): The guaiac faecal occult blood test was the first stool test used for bowel screening: six smears from three separate stools, read by a colour change when blood is present. It is the test that proved in randomised trials that bowel screening saves lives, an...Open in Atlas Source
Familial pancreatic cancer and inherited risk (who qualifies for surveillance): Familial pancreatic cancer means at least two close relatives on the same side of the family have had the disease without a known gene fault to explain it. Members of such families have several times the usual risk, rising steeply with the number of relativ...Open in Atlas Source
Family Smoking Prevention and Tobacco Control Act 2009: The 2009 US law that finally gave the FDA power over tobacco products, the cause of roughly a third of cancer deaths, including authority to ban flavours, restrict marketing and set nicotine levels, though it may not ban cigarettes or nicotine outright.Open in Atlas Source
Fast Track and RMAT designations: Two of the FDA's expedited programmes: Fast Track gives drugs for serious unmet needs more frequent FDA meetings and rolling review; RMAT is the equivalent for cell and gene therapies. Neither guarantees approval or changes the evidence standard.Open in Atlas Source
Fatigue after lymphoma treatment, and why it is a symptom to report: The tiredness that follows lymphoma treatment is not ordinary tiredness and does not reliably improve with rest. Several of its causes, including anaemia, an underactive thyroid, poor sleep and low mood, are separate and separately treatable, which is the r...Open in Atlas Source
Fc engineering / effector function: Tweaking the antibody's tail to make it recruit immune cells more strongly, or not at all.Open in Atlas Source
FDA laboratory-developed test (LDT) rule: Most cancer tests in the US, including Galleri, Signatera and Oncotype DX, are 'lab-developed tests' overseen through lab standards rather than FDA approval; the FDA's 2024 attempt to change that was struck down in court in 2025.Open in Atlas Source
FDASIA 2012 and the origins of the expedited programmes: The 2012 US law that created Breakthrough Therapy designation and made the paediatric study laws permanent, sitting on top of the 1992 user-fee law that gave the FDA review deadlines and the 1997 law that created Fast Track.Open in Atlas Source
FDORA 2022 accelerated approval reforms: A December 2022 US law that lets the FDA insist the confirmatory trial for an accelerated approval is already running before the drug is approved, and gives it a quicker way to withdraw a drug when confirmation fails.Open in Atlas Source
Febrile neutropenia: Fever in a patient whose infection-fighting white cells have been wiped out by chemotherapy. It is a medical emergency: without immune cells, an ordinary infection can become fatal in hours, so antibiotics are started immediately.Open in Atlas Source
Federal Food, Drug, and Cosmetic Act and the Kefauver-Harris Amendments: The 1938 US law that makes a company prove a medicine is safe before selling it, and the 1962 amendments that added the requirement to prove it works, which is why every cancer drug approval rests on controlled trials.Open in Atlas Source
Feeding tube (gastrostomy, PEG, jejunostomy): A tube placed into the stomach (gastrostomy, PEG) or small bowel (jejunostomy) so a patient who cannot swallow enough can still be fed through the gut.Open in Atlas Source
Fertility before lymphoma treatment: what to ask for, and when: Several lymphoma treatments can end fertility, and the chance to preserve it exists only before the first dose. Lymphoma often strikes people in their teens, twenties and thirties, which makes this one of the few conversations that cannot be postponed.Open in Atlas Source
Fertility preservation before lymphoma treatment: a decision with a deadline in days: Most of the ways of preserving fertility have to happen before the first dose of chemotherapy, and two of them take about a fortnight. Lymphoma is often treated quickly, so this is one of the few decisions in the illness with a real deadline, and it is easy...Open in Atlas Source
FGFR2 fusions and rearrangements: A broken-and-rejoined FGFR2 gene that drives about one in eight intrahepatic bile duct cancers and can be switched off with pills.Open in Atlas Source
FGFR3 alterations (bladder cancer): FGFR3 is a growth-receptor gene mutated or fused in about a fifth of advanced bladder cancers and most low-grade early ones. It is the only targetable biomarker in bladder cancer so far.Open in Atlas Source
Fibroblast subtypes in the pancreatic cancer stroma (myCAF, iCAF and apCAF): The fibroblasts that make up most of a pancreatic tumour are not one cell type. Those pressed against the cancer cells become contractile myofibroblasts (myCAF), those further away secrete inflammatory signals (iCAF), and a third group carries antigen-prese...Open in Atlas Source
Fiducial markers: Tiny gold seeds or electromagnetic beacons placed in or near a tumour so the treatment machine can see exactly where it is each day.Open in Atlas Source
Financial toxicity: The harm caused to patients by the cost of cancer care: depleted savings, debt, skipped medication and worse survival. Measured like any other side effect and, increasingly, treated like one.Open in Atlas Source
Fine-tuning versus frozen features, and LoRA: Fine-tuning updates a pretrained model's weights on the new task; using it frozen keeps the weights fixed and trains only a small head on its features; LoRA is a cheap middle way that trains small low-rank updates.Open in Atlas Source
First-in-human (FIH) trial: The first time a new drug is given to people, after animal and laboratory testing and clearance of an Investigational New Drug application. In oncology these are phase 1 trials in patients with advanced cancer who have exhausted standard options, starting a...Open in Atlas Source
FISH / ISH (in situ hybridisation): A test that uses glowing DNA probes on a tissue slide to count gene copies or spot rearranged genes inside individual cells, used to confirm HER2 amplification, MYCN in neuroblastoma, or ALK and MYC rearrangements.Open in Atlas Source
Fixed-duration vs continuous therapy: Whether a drug is taken for a set period (say 12 months) and then stopped even though it is still working, or continued indefinitely until it fails. Fixed-duration gives patients years off treatment; continuous therapy avoids the risk of the cancer regrowing.Open in Atlas Source
FLIPI, FLIPI2 and POD24 (follicular lymphoma risk): FLIPI counts five simple things (age over 60, stage III or IV, more than four node areas, raised LDH, low haemoglobin) to predict how a follicular lymphoma will behave; POD24, relapse within two years of starting chemo-immunotherapy, is the single strongest...Open in Atlas Source
FLOT regimen (perioperative chemotherapy for gastric cancer): Four cycles of chemotherapy before and four after surgery for stomach and junction cancer, using fluorouracil, leucovorin, oxaliplatin and docetaxel. It replaced the older ECF recipe after the FLOT4 trial and is now the Western standard.Open in Atlas Source
Flow cytometry (immunophenotyping): A machine that streams cells one by one past lasers and reads the surface proteins (CD markers) each carries, identifying what kind of cell it is. It is how leukaemias and lymphomas are typed and how residual disease is counted.Open in Atlas Source
FLT3-ITD allelic ratio: How much of the FLT3 gene in the leukaemia carries the internal duplication, measured as the ratio of mutant to normal copies. The 2017 European LeukemiaNet guidelines used it to grade risk; the 2022 update dropped it because midostaurin and quizartinib hel...Open in Atlas Source
FNCLCC grade (soft-tissue sarcoma): The FNCLCC grade is a 1-to-3 score for soft-tissue sarcomas based on how abnormal, how fast-dividing, and how much dead tissue the tumour shows; grade drives whether chemotherapy is considered.Open in Atlas Source
Focal and tissue-preserving treatment of prostate cancer: Treating only the part of the prostate that contains the cancer, with heat, cold or light, preserves erections and continence better than removing or irradiating the whole gland. No randomised trial has shown it controls cancer as well, and in England it is...Open in Atlas Source
FOLFOX, FOLFIRI, FOLFIRINOX and CAPOX: The standard chemotherapy recipes for bowel and pancreatic cancer, named from their ingredients: FOL (folinic acid) + F (5-fluorouracil) + OX (oxaliplatin), IRI (irinotecan), or both (FOLFIRINOX). CAPOX swaps the 5-FU infusion for capecitabine tablets.Open in Atlas Source
Foundation model: A foundation model is a large model trained on a vast amount of data without a specific task in mind, then adapted to many downstream uses.Open in Atlas Source
Founder mutation (BRCA1 185delAG and 5382insC, BRCA2 6174delT): A founder mutation is a single inherited gene fault that many people in one population share because they descend from the same ancestor who carried it. The best known are three BRCA faults carried by about one in forty Ashkenazi Jews, which is why Jewish a...Open in Atlas Source
Founder variant: A disease-causing genetic change that is common in one population because many of its members descend from a small group of ancestors who happened to carry it. It says nothing about whether any particular person has it, and a negative founder test does not...Open in Atlas Source
FOXO1 fusion status and IRS group (rhabdomyosarcoma): Rhabdomyosarcoma used to be sorted by what it looked like (alveolar or embryonal); it is now sorted by whether the PAX3 or PAX7 gene is fused to FOXO1, because fusion-positive tumours relapse far more often whatever their appearance, and together with the s...Open in Atlas Source
France: early access (accès précoce), formerly ATU: France pays for promising medicines before they are approved or reimbursed: the ATU system did this from 1994, and since July 2021 the Haute Autorité de Santé grants early access for presumed innovative drugs in serious diseases, with the company setting th...Open in Atlas Source
From a clone in the blood to a leukaemia: what is known, and what is done: Chemotherapy and radiotherapy select for blood stem cells carrying particular mutations, and in a small minority one of those clones becomes a leukaemia. The useful question is not whether a clone is there but whether it will progress: most never do, and no...Open in Atlas Source
Full (traditional, regular) approval: The ordinary form of drug approval, granted when a trial has shown real clinical benefit such as longer survival, as opposed to an accelerated approval granted on an early stand-in measure and still awaiting confirmation.Open in Atlas Source
Futility analysis (stopped for futility): A planned check partway through a trial to see whether the new treatment has any realistic chance of proving better; if not, the trial is stopped to spare patients and money. The opposite rule stops a trial early when benefit is overwhelming.Open in Atlas Source

G

Gallbladder cancer in biliary tract cancer trials (eligibility and subgroups): Almost every drug trial for gallbladder cancer also enrols bile duct cancers, so the evidence comes from mixed groups in which gallbladder cancer is usually a fifth to a half of patients. This entry lists the trials open to people with gallbladder cancer an...Open in Atlas Source
Gallbladder polyp (polypoid lesion): A small growth on the inside wall of the gallbladder, usually spotted by chance on an ultrasound scan. Most are harmless cholesterol deposits; the risk of cancer rises with size, so polyps of 10 mm or more are removed with the gallbladder and smaller ones a...Open in Atlas Source
Gastrectomy: Removing part (subtotal) or all (total) of the stomach for stomach cancer, with the bowel joined to what remains.Open in Atlas Source
Gastro-oesophageal junction (GEJ): Where the food pipe meets the stomach. Cancers here are classed by how far above or below the junction they centre (Siewert I-III), which decides whether they are treated like oesophageal or stomach cancer.Open in Atlas Source
GATA6 as the marker of classical versus basal-like pancreatic cancer: GATA6 is the transcription factor that separates the two pancreatic cancer subtypes that survive every re-analysis: classical tumours express it, basal-like (squamous) tumours have lost it. A GATA6 stain on a biopsy can therefore call the subtype that predi...Open in Atlas Source
GDPR and health data (Regulation (EU) 2016/679): The EU's 2016 data law, applied since May 2018, that treats health and genetic data as a special category needing a specific legal basis, gives people rights over their records, and shapes how cancer registries, biobanks and trials share data, including acr...Open in Atlas Source
Gene: A stretch of DNA that holds the recipe for one protein (or one working RNA). Humans have about 20,000, and cancer typically involves a handful of them going wrong.Open in Atlas Source
Gene amplification and copy-number change: Cancer cells often have extra copies of a growth gene (amplification) or have lost copies of a protective one (deletion), rather than a spelling change within the gene. Extra copies of HER2 or MYCN are classic examples that change treatment.Open in Atlas Source
Gene co-expression structure: Genes that rise and fall together across samples form co-expression modules; this correlation structure is what expression models mostly learn.Open in Atlas Source
Gene expression: How much a gene is switched on, and therefore how much of its protein a cell makes. Cancer cells often express the wrong genes at the wrong levels.Open in Atlas Source
Gene fusion: A gene fusion is two genes broken and joined together, creating a hybrid protein that can drive cancer. Fusion-driven cancers are often exquisitely drug-sensitive.Open in Atlas Source
Gene set enrichment analysis (GSEA and ssGSEA): Gene set enrichment analysis asks whether the genes that changed in an experiment cluster in a known pathway or signature, turning a list of genes into a biological story.Open in Atlas Source
Genome builds: GRCh38 versus hg19 (GRCh37): A genome build is the version of the human reference sequence coordinates are measured against; mixing GRCh38 and the older hg19 puts variants at the wrong positions.Open in Atlas Source
Genome-wide loss of heterozygosity (gLOH): A score for how much of a tumour's genome has lost one of its two parental copies. A high score is a scar left behind by a broken DNA repair system, and is used as a rough sign that a PARP inhibitor might work. It is a measure of damage already done, not of...Open in Atlas Source
Genomic and protein language models: Evo 2, Enformer, ESM: Sequence models read DNA or protein letters the way language models read text: ESM predicts protein structure and function, Enformer predicts gene expression from DNA sequence, and Evo 2 models whole genomes with a million-base context.Open in Atlas Source
Genomic profiling: Reading the DNA (and sometimes RNA) of a tumour, usually with a panel of a few hundred genes, to list its mutations, fusions and amplifications and match them to approved drugs or trials. Guidelines now require it before first-line treatment in lung, colore...Open in Atlas Source
Germline BRCA mutation (gBRCA): An inherited fault in the BRCA1 or BRCA2 gene, present in every cell from birth, that greatly raises the risk of breast, ovarian, prostate and pancreatic cancer and makes those cancers sensitive to PARP inhibitors and platinum.Open in Atlas Source
Germline BRCA testing criteria for triple-negative breast cancer (UK): In the NHS a blood test for inherited BRCA1 and BRCA2 faults is offered to every woman under 50 with triple-negative breast cancer, whatever her family history, and hospital testing criteria now extend that to triple-negative disease under 60 and any breast...Open in Atlas Source
Germline vs somatic mutations: Germline mutations are inherited and in every cell; somatic mutations arise in the tumour only.Open in Atlas Source
GINA (Genetic Information Nondiscrimination Act 2008): A 2008 US law that stops health insurers and employers using your genetic test results against you, so a BRCA or Lynch syndrome result cannot raise your premiums or cost you a job; it does not cover life, disability or long-term care insurance.Open in Atlas Source
GIST risk stratification (mitotic count, size, site; Miettinen and modified NIH criteria): Whether a gastrointestinal stromal tumour will come back after surgery is read from three things on the pathology report, its size, how many cells are dividing in a 5 square millimetre field, and where it started (stomach is safer than small bowel or rectum...Open in Atlas Source
GISTIC (copy number driver detection): GISTIC scans copy number data across many tumours to find the regions that are amplified or deleted far more often than chance, the likely targets of selection.Open in Atlas Source
Gleason score / Grade Group: The pathologist's 1-to-5 grade of how abnormal prostate cancer looks, which drives most treatment decisions.Open in Atlas Source
Glycaemic index and glycaemic load: How fast a food raises blood sugar (index) and how much, given the portion (load). High-glycaemic-load diets are weakly linked to some cancers, largely via obesity and insulin.Open in Atlas Source
Going back to work after lymphoma, and the money in the meantime: Some people work through lymphoma treatment and some cannot, and the difference is mostly the job rather than the person. In the United Kingdom a cancer diagnosis brings protection from discrimination at work from the day it is made, and the benefits and si...Open in Atlas Source
GPU training and mixed precision: Foundation models are trained on graphics processors, and mixed precision stores most numbers in 16-bit floats to halve memory and double speed; a laptop-class chip can fine-tune small models but pretraining at scale waits for a data-centre GPU.Open in Atlas Source
Grade: How abnormal the cancer cells look under the microscope, from grade 1 (close to normal, slow) to grade 3 or 4 (wildly abnormal, fast). Grade is about behaviour; stage is about extent.Open in Atlas Source
Grade versus stage: Grade describes how abnormal the cancer cells look under the microscope; stage describes how far the cancer has grown and spread.Open in Atlas Source
Grade, stage and receptor status: three different things on one breast report: A breast report gives three answers to three different questions: the grade says how the cells behave, the stage says how far the cancer has gone, and the receptors say which drugs it will respond to. None of the three can be worked out from the others, and...Open in Atlas Source
Graded Prognostic Assessment (GPA) for brain metastases: The GPA is a points score (age, performance status, number of brain metastases, spread outside the brain, and for some cancers the tumour's mutations) that estimates survival for a patient with brain metastases from a few months to several years, and it is...Open in Atlas Source
Graft-versus-host disease (GVHD) and graft-versus-leukaemia: After a donor transplant, the donor's immune cells may attack the patient's skin, gut and liver (graft-versus-host disease) while also hunting down leftover leukaemia (graft-versus-leukaemia). The two effects are linked, so doctors try to keep enough of the...Open in Atlas Source
Gray unit (Gy): The unit of radiation dose absorbed by tissue: one gray is one joule per kilogram. A curative course is typically 50-70 Gy in total; a single bone-pain treatment is 8 Gy. Radiopharmaceuticals are prescribed by activity in becquerels (GBq) instead.Open in Atlas Source
Group sequential design, stopping rules and alpha spending: A group sequential trial plans in advance how many times it will peek at the data and how strong the evidence must be at each peek to stop early, so that looking several times does not inflate the chance of a false positive.Open in Atlas Source
Growth factor: A protein released by one cell that tells nearby cells to grow, divide or survive. Cancers often make their own or become hypersensitive to it.Open in Atlas Source
Growth signal: The instruction a cell receives to grow and divide. Normal cells wait for it; cancer cells fake it, so they keep dividing whether or not the body wants more of them.Open in Atlas Source
GTV, CTV and PTV (target volumes): The nested outlines a radiation plan is built on: the visible tumour (GTV), the tumour plus the tissue likely to hold microscopic spread (CTV), and a further margin for daily movement and setup error (PTV).Open in Atlas Source
Gut microbiome diversity and composition: How many different kinds of bacteria live in the gut and which ones dominate. Higher diversity and certain species are linked with better immunotherapy response; antibiotics and poor diet reduce both.Open in Atlas Source
Gynaecomastia: Swelling and tenderness of the chest caused by hormone treatment, ranging from mild sensitivity to noticeable breasts.Open in Atlas Source

H

H&E staining (haematoxylin and eosin): H&E is the purple and pink stain on almost every pathology slide: haematoxylin colours cell nuclei blue-purple and eosin colours the cytoplasm and connective tissue pink.Open in Atlas Source
H3 K27M (diffuse midline glioma): A single change in a histone protein that defines diffuse midline glioma, the childhood brain tumour with the fewest treatment options, and now the target of the first approved drug for it.Open in Atlas Source
Haematocrit: The share of blood volume made up of red cells. Normal is roughly 40 to 50 percent; in polycythaemia vera treatment aims to keep it under 45 percent, because above that clots become much more likely.Open in Atlas Source
Haemoptysis (coughing up blood): Coughing up blood, or blood-streaked phlegm. It has many causes other than cancer, including chest infection, but it is the one lung symptom that sends a person aged 40 or over straight onto the suspected cancer pathway rather than to an X-ray first.Open in Atlas Source
Hair loss and scalp cooling with breast cancer chemotherapy: Taxane and anthracycline chemotherapy for triple-negative breast cancer causes hair loss in most people, usually starting after the first or second cycle and almost always growing back; scalp cooling kept more than half the hair in about half of women in a...Open in Atlas Source
Half-life: The time it takes for the amount of a drug in the blood to fall by half. It sets how often a drug must be given: hours to a day for small molecules such as kinase inhibitors, so they are taken daily, and two to four weeks for antibodies, so they are given e...Open in Atlas Source
Hallmark (2022): non-mutational epigenetic reprogramming: Cancers can change behaviour, including becoming drug-tolerant, without any new mutation, by rewriting the chemical tags that control which genes are read.Open in Atlas Source
Hallmark (2022): polymorphic microbiomes: The bacteria living in and around us differ from person to person and influence cancer risk, progression, and how well treatments work.Open in Atlas Source
Hallmark (2022): senescent cells: Cells that have permanently stopped dividing but stay alive and secrete inflammatory signals, helping nearby cancer cells grow and resist treatment.Open in Atlas Source
Hallmark (2022): unlocking phenotypic plasticity: Cancer cells escape the normal rule that mature cells stay what they are: they dedifferentiate, transdifferentiate, or refuse to mature.Open in Atlas Source
Hallmark: activating invasion and metastasis: Cancer cells detach, invade, travel, and colonise other organs, the process responsible for most cancer deaths.Open in Atlas Source
Hallmark: avoiding immune destruction: Cancers hide from or switch off the immune system, by losing the molecules that display their antigens or by raising checkpoint brakes.Open in Atlas Source
Hallmark: enabling replicative immortality: Cancer cells bypass the division limit set by shortening telomeres, usually by reactivating telomerase.Open in Atlas Source
Hallmark: evading growth suppressors: Evading growth suppressors means cutting the brakes that normally stop division, p53 and RB above all.Open in Atlas Source
Hallmark: inducing or accessing vasculature: Tumours grow their own blood supply, or co-opt existing vessels, to get oxygen and nutrients.Open in Atlas Source
Hallmark: reprogramming cellular metabolism: Cancer cells rewire their metabolism to build biomass fast, burning glucose inefficiently and gorging on glutamine and lipids.Open in Atlas Source
Hallmark: resisting cell death: Resisting cell death is the hallmark by which cancer cells disable their self-destruct programmes, chiefly apoptosis.Open in Atlas Source
Hallmark: sustaining proliferative signalling: Cancer cells keep telling themselves to divide, by making their own growth signals or jamming the receptors on.Open in Atlas Source
Hallmarks of Cancer: The Hallmarks of Cancer is the most-cited framework in cancer biology: a short list of the capabilities every cancer must acquire, from unlimited growth to hiding from the immune system. The 2022 update lists eight hallmarks, two enabling characteristics, a...Open in Atlas Source
Hallmarks of cancer as a synthesis of the theories: Rather than asking what starts cancer, Hanahan and Weinberg asked what every cancer ends up able to do: keep growing, ignore stop signals, avoid death, live forever, grow vessels, invade, rewire metabolism and hide from the immune system. Each update has ab...Open in Atlas Source
Hand-foot syndrome and hand-foot skin reaction: Redness, peeling, pain and cracking of the palms and soles caused by certain chemotherapy pills and by kinase inhibitors that block blood vessel growth. Rarely dangerous but can stop patients walking or using their hands.Open in Atlas Source
Hatch-Waxman Act 1984: The 1984 US law that created the modern generic drug: copies are approved on bioequivalence alone, brands get patent time restored for years lost in review, and the two sides fight it out through patent challenges with a 30-month pause.Open in Atlas Source
Hazard ratio (HR): A hazard ratio is a number comparing the rate of bad events in two groups. An HR of 0.5 means the risk is halved at any moment.Open in Atlas Source
Head and neck subsites (oral cavity, oropharynx, larynx): Head and neck cancer is really several cancers named by exact location: mouth (oral cavity), back of the throat (oropharynx, where HPV cancers arise), voice box (larynx), lower throat (hypopharynx) and behind the nose (nasopharynx). Each behaves and is trea...Open in Atlas Source
Health disparities in cancer outcomes (ethnicity, deprivation and access): Health disparities are differences in who gets a cancer and who survives it that track ethnicity, income and access to care rather than chance. Triple-negative breast cancer is the textbook case: Black women get it about twice as often, present later and di...Open in Atlas Source
Health technology assessment (HTA), reimbursement and QALYs: Approval says a drug works; reimbursement says who will pay. Health technology assessment bodies (NICE, G-BA, PBAC) judge whether the benefit is worth the price, often per quality-adjusted life year, and can delay access for years after approval.Open in Atlas Source
Helicobacter pylori eradication as cancer treatment in gastric MALT lymphoma: Gastric MALT lymphoma is grown by a stomach bacterium, and killing the bacterium with a ten to fourteen day course of antibiotics cures most cases. It is the only common cancer whose first-line treatment is an antibiotic.Open in Atlas Source
Hepatectomy (liver resection): Cutting out the part of the liver containing tumour. The liver regrows, so up to 70% can be removed if what remains is healthy.Open in Atlas Source
Hepatitis B and C as cancer causes: Two viruses cause most liver cancer worldwide. One is preventable by vaccine, the other curable with pills, which makes liver cancer one of the most preventable cancers.Open in Atlas Source
Hepatitis B reactivation before rituximab and other anti-CD20 antibodies: Anyone who has ever had hepatitis B can have the virus wake up when rituximab strips out their B cells, sometimes months later and sometimes fatally. A blood test before the first dose, and a tablet for those who need it, prevents almost all of it.Open in Atlas Source
Hepatotoxicity (liver enzyme elevation): Liver injury from a drug, usually detected as a rise in liver enzymes (ALT, AST) on routine blood tests before symptoms appear. Most cases settle with a pause or dose reduction; a few, especially with checkpoint inhibitors or in already damaged livers, are...Open in Atlas Source
Hepcidin: The liver hormone that controls how much iron the body absorbs and releases. Drugs that mimic it lock iron away so the marrow cannot make excess red cells, the idea behind rusfertide.Open in Atlas Source
HER2 and genomic testing for biliary cancer on the NHS: Asking for HER2 testing and a tumour gene panel at diagnosis of advanced gallbladder cancer is reasonable, because about one in ten tumours is HER2-positive on staining (more carry a HER2 gene change) and a HER2 antibody is now funded on the NHS; the test i...Open in Atlas Source
HER2 testing in biliary tract cancer (IHC, ISH and NGS): Bile duct and gallbladder tumours are scored for HER2 with the stomach cancer rules, not the breast ones, and a strong stain (3+) is enough for zanidatamab. A borderline stain (2+) needs a gene-copy test, and a sequencing panel can find both the amplificati...Open in Atlas Source
HER2 testing in the UK: reflex ISH, the ratio against the copy number, and where the UK differs from ASCO/CAP: HER2 is scored 0 to 3+ on the stain; 3+ is positive, 0 and 1+ are negative, and 2+ goes on for a gene test. The UK reads one borderline gene result as positive where the American guideline reads it as negative, so the same tumour can be HER2-positive in Bri...Open in Atlas Source
HER2-low and HER2-ultralow: Tumours with a little HER2 (IHC 1+ or 2+ without amplification), or a trace (ultralow), which older HER2 drugs ignored but Enhertu can attack.Open in Atlas Source
HER2-low eligibility for trastuzumab deruxtecan, and TROP2 ADCs without a test (triple-negative disease): Two antibody-drug conjugates reach triple-negative breast cancer by different rules. Trastuzumab deruxtecan needs the tumour to show a little HER2 (a score of 1+, or 2+ without gene amplification), so the pathologist's call between 0 and 1+ matters. Sacituz...Open in Atlas Source
HER2-positive (IHC 3+ or ISH-amplified): A cancer with too much HER2 growth-signal protein, either scored 3+ on the stain or shown to have extra copies of the gene. Once the most aggressive breast cancer subtype, it is now among the most treatable thanks to anti-HER2 drugs.Open in Atlas Source
HER2-positive brain metastases: Up to half of women with metastatic HER2-positive breast cancer develop brain metastases, because antibodies control the body but historically not the brain.Open in Atlas Source
HERACLES criteria (HER2 in bowel cancer): Bowel cancer needed its own rule for calling a tumour HER2-positive, because the rules written for breast and stomach cancer did not transfer. The HERACLES criteria are that rule: intense membrane staining in more than half the cells, confirmed by gene ampl...Open in Atlas Source
Hereditary cancer syndromes: About 5-10% of cancers arise from an inherited gene fault. Recognising the syndromes (BRCA, Lynch, Li-Fraumeni, VHL, MEN, FAP, retinoblastoma and dozens more) changes screening, surgery and treatment for the patient and their relatives.Open in Atlas Source
HGNC gene symbol: The HGNC symbol is the one official short name for each human gene (ERBB2, not HER2 or NEU), so that datasets can be joined without guessing.Open in Atlas Source
HGVS variant nomenclature: HGVS is the standard way to write a DNA or protein change, such as EGFR c.2573T>G or p.Leu858Arg, so that the same variant is named the same way everywhere.Open in Atlas Source
HHV-8 (KSHV) status and LANA-1 immunohistochemistry: Kaposi sarcoma, primary effusion lymphoma and one form of Castleman disease are all caused by human herpesvirus 8; a nuclear stain for its LANA-1 protein confirms the diagnosis on a biopsy, and the amount of virus in the blood tracks the dangerous inflammat...Open in Atlas Source
High-grade prostatic intraepithelial neoplasia (HGPIN): Abnormal cells lining prostate ducts that are not cancer and are not treated. On its own it is a finding, not a diagnosis; what matters is whether it is widespread and whether anything more atypical was seen beside it.Open in Atlas Source
High-grade serous ovarian carcinoma (HGSOC): High-grade serous ovarian carcinoma is the most common type of ovarian cancer and the one most often found late; it actually starts in the fallopian tube and almost always has a broken TP53 gene, and it is the type PARP inhibitors were built for.Open in Atlas Source
High-risk cytogenetics (myeloma): Chromosome changes such as del(17p), t(4;14), t(14;16) and extra copies of 1q that mark myeloma likely to relapse early.Open in Atlas Source
High-risk stigmata and worrisome features of pancreatic cysts (IPMN and MCN surgical criteria): Most pancreatic cysts never become cancer, so doctors watch them and operate only when warning signs appear. The strongest signs, the high-risk stigmata, are jaundice from a cyst in the head of the pancreas, a solid lump inside the cyst that lights up with...Open in Atlas Source
HIPAA (Health Insurance Portability and Accountability Act): The 1996 US law whose privacy rules govern how hospitals, insurers and their contractors may use and share a patient's health records, including tumour genomics, and what must be stripped out before data can be used for research without consent.Open in Atlas Source
HIPEC (hyperthermic intraperitoneal chemotherapy): After surgeons remove all visible tumour from the abdominal lining, the abdomen is bathed for 60-90 minutes in heated chemotherapy to kill the microscopic cells left behind.Open in Atlas Source
Histologic transformation: When a lung adenocarcinoma escapes targeted therapy by turning into a different cell type, usually small-cell.Open in Atlas Source
Histological response to induction chemotherapy (osteosarcoma and Ewing sarcoma): After ten weeks of chemotherapy a bone sarcoma is removed and the pathologist maps how much of it is dead; 90 percent or more necrosis (a good response) predicts cure in most children, under 90 percent predicts relapse, but the EURAMOS-1 trial showed that p...Open in Atlas Source
Histology: The study of tissue under the microscope. A cancer's histology is what kind of cells it is made of and how they are arranged, which is how a pathologist names it and grades it.Open in Atlas Source
Histotype-tailored therapy: Histotype-tailored therapy means choosing treatment by the specific sarcoma subtype (there are more than 70) rather than treating all sarcomas alike.Open in Atlas Source
HLA-A*02:01 restriction: Some T-cell-receptor drugs only work in people with a particular immune 'tissue type'. About half of people of European ancestry have it; far fewer in some other populations.Open in Atlas Source
Homologous recombination deficiency (HRD): A tumour that cannot properly repair double-strand DNA breaks, usually because of BRCA or related gene loss.Open in Atlas Source
Homologous recombination deficiency (HRD) in breast cancer: Homologous recombination deficiency means a tumour cannot mend double-strand DNA breaks properly, most often because BRCA1 or BRCA2 is lost. About seven in ten triple-negative tumours score as deficient, and they respond better to platinum chemotherapy; but...Open in Atlas Source
Hormone receptor status (ER / PR): Whether a breast cancer's cells carry receptors for oestrogen (ER) and progesterone (PR). If they do, the cancer is fed by these hormones and can be treated by blocking them; about 70% of breast cancers are hormone receptor-positive.Open in Atlas Source
Hormone therapy: Treatment that starves cancers which grow in response to a hormone, mainly oestrogen in breast cancer and testosterone in prostate cancer, by lowering the hormone or blocking its receptor.Open in Atlas Source
Hot flushes on hormone therapy: Sudden waves of heat and sweating caused by losing testosterone: the commonest complaint on hormone therapy for prostate cancer.Open in Atlas Source
Hot vs cold tumours: 'Hot' tumours are full of immune cells and respond to immunotherapy; 'cold' tumours have kept the immune system out.Open in Atlas Source
How ER and PR are scored on a breast report (Allred score, H score, and why PR is not a UK core item): The oestrogen receptor test counts stained nuclei under a microscope and reports a percentage with an intensity, sometimes summarised as an Allred score out of 8 or an H score out of 300. There is no single agreed scoring method, the result is close to all-...Open in Atlas Source
How many radiotherapy visits: the prostate fractionation trials: Prostate cancer responds unusually well to a few large doses of radiation rather than many small ones, so a course that used to take eight weeks now takes four weeks, or two, or one.Open in Atlas Source
How skin carcinoma is staged in Britain: UICC TNM, and why it is not the American system: UK skin carcinoma reports are staged against the UICC's system, not the American AJCC's, and the two are not the same: the American manual covers only the head and neck, while the UICC covers the whole body and includes basal cell carcinoma. In practice alm...Open in Atlas Source
HPV status (HPV-positive / HPV-negative): Whether a cancer is caused by human papillomavirus. HPV-positive throat cancers are a different, far more curable disease than smoking-related ones, and the virus's DNA in blood can track the cancer.Open in Atlas Source
HPV-positive (p16) head and neck cancer: Throat cancers caused by the human papillomavirus, identified by a p16 stain. They affect younger non-smokers and are far more curable than tobacco-related cancers.Open in Atlas Source
HTLV-1 (human T-lymphotropic virus type 1): A virus that infects T cells, is passed mainly through breastfeeding and sexual contact, and causes a lymphoma decades later in a small minority of the people it infects. It is common in south-western Japan, the Caribbean, west and central Africa, parts of...Open in Atlas Source
HTLV-1, Tax and HBZ in adult T-cell leukaemia/lymphoma: A virus passed mostly from mother to child in breast milk, common in parts of Japan, the Caribbean, west Africa and South America. Most people who carry it never become ill, but in a few it causes an aggressive T-cell cancer decades later.Open in Atlas Source
Hugging Face Hub: The Hugging Face Hub is the website where most machine-learning models and many datasets are published, with a model card, version history and, for gated models, an access request form.Open in Atlas Source
Human Phenotype Ontology (HPO): The Human Phenotype Ontology is a standard vocabulary of clinical features (signs, symptoms, findings) with codes, used to describe patients in a way computers can compare.Open in Atlas Source
Hydrophilic next-generation linkers (TMALIN, Dolaflexin, sulfonyl-pyrimidine, PEG-containing): Hydrophilic next-generation linkers have built-in sugars or polyethylene glycol that let ADCs carry more payload without clumping, and they resist efflux pumps.Open in Atlas Source
Hyperglycaemia (PI3K/AKT inhibitor class effect): High blood sugar as a side effect of drugs that block the PI3K/AKT pathway, because the same pathway carries insulin's signal in muscle and liver. It is the main reason these otherwise effective breast cancer drugs are hard to give.Open in Atlas Source
Hypofractionation (fewer, larger radiotherapy doses): Giving radiotherapy in fewer, bigger daily doses (fractions) so a course takes one to three weeks instead of five to seven. Randomised trials showed equal control and side effects in breast (START, FAST-Forward) and prostate (CHHiP, PACE-B) cancer, and a si...Open in Atlas Source
Hypogammaglobulinaemia and infection risk after B-cell therapies: A shortage of antibodies because treatment has wiped out the B cells or plasma cells that make them, as CD19 CAR-T, CD20 antibodies and BCMA therapies deliberately do. It leaves patients prone to infections, sometimes for years, and is managed with immunogl...Open in Atlas Source
Hypomethylating agents (azacitidine, decitabine): Low-intensity chemotherapy that strips chemical 'off' switches (methyl groups) from DNA so silenced genes can be read again. The mainstay for older patients with AML and high-risk MDS, especially combined with venetoclax.Open in Atlas Source
Hysterectomy: Removing the uterus (womb), often with the cervix, tubes and ovaries. Simple hysterectomy is the standard curative operation for endometrial cancer, and radical hysterectomy, which also removes tissue beside the cervix and the upper vagina, treats early cer...Open in Atlas Source

I

ICANS (neurotoxicity): ICANS is confusion, speech difficulty, and rarely seizures after CAR-T or bispecific therapy.Open in Atlas Source
ICD-O-3 (International Classification of Diseases for Oncology): ICD-O-3 codes every tumour twice: a topography code for where it arose and a morphology code for what kind of cells it is made of and how it behaves.Open in Atlas Source
ICER and health technology assessment: Independent bodies that judge whether a new cancer drug's benefit is worth its price; decisive for coverage outside the US and increasingly inside it.Open in Atlas Source
ICH good clinical practice (E6): The international standard for how a clinical trial must be designed, run, recorded and reported so that regulators in the United States, Europe, Japan and now China will accept its data; the third version was adopted in 2025 to fit trials that use electron...Open in Atlas Source
IGHV mutational status: Whether the leukaemia's antibody gene has been 'edited' by the immune system. Unmutated means faster-growing CLL and a bigger benefit from targeted drugs over chemotherapy.Open in Atlas Source
ILAP (Innovative Licensing and Access Pathway): The UK's post-Brexit scheme, launched in 2021 and refreshed in 2025, that brings the medicines regulator, NICE and the NHS together early in a drug's development so that licensing and the decision to pay for it can happen close together.Open in Atlas Source
IMDC risk groups (favourable / intermediate / poor): The IMDC score uses six factors to sort metastatic kidney cancer into three risk groups. It decides whether dual immunotherapy or immunotherapy plus a targeted pill is offered first.Open in Atlas Source
Immune checkpoint: Brakes on the immune system that stop T cells attacking healthy tissue. Tumours pull these brakes to protect themselves; checkpoint inhibitor drugs release them so T cells can attack the cancer.Open in Atlas Source
Immune exclusion: A tumour where the immune cells arrive but are stopped at the edge, held back by scar tissue and signals such as TGF-β.Open in Atlas Source
Immune surveillance and cancer immunoediting: The immune system patrols for cells that have turned malignant and destroys most of them; the tumours we see are the ones that learned to hide. Ehrlich guessed this in 1909, Burnet and Thomas argued it in the 1950s, it was declared dead in the 1970s, and Ro...Open in Atlas Source
Immune system: The body's defence network of cells and molecules that recognises and destroys infected, foreign and abnormal cells. It kills most would-be cancers before they are ever noticed; the ones that survive have learned to hide from it.Open in Atlas Source
Immune-mediated colitis and diarrhoea: Inflammation of the bowel caused by immunotherapy releasing the immune system against the gut lining, producing diarrhoea that can be severe. It is the commonest serious side effect of CTLA-4 antibodies and is treated with steroids and, if needed, infliximab.Open in Atlas Source
Immune-related adverse events (irAEs): Immune-related adverse events (irAEs) are the autoimmune side effects of checkpoint inhibitors: colitis, thyroid problems, rash, hepatitis, pneumonitis.Open in Atlas Source
Immune-related endocrinopathies (thyroiditis, hypophysitis): Immunotherapy can attack hormone-producing glands: most often the thyroid (usually ending in an under-active thyroid needing lifelong tablets), and less often the pituitary (hypophysitis) or adrenal glands, which can be life-threatening if missed.Open in Atlas Source
Immune-related myocarditis: Rare but frequently fatal inflammation of the heart muscle triggered by checkpoint inhibitors, usually in the first two months. It often comes with muscle and nerve-muscle inflammation, and needs urgent high-dose steroids.Open in Atlas Source
Immuno-oncology (IO) and checkpoint blockade: Treatments that take the brakes off the patient's own immune system so it attacks the cancer, chiefly antibodies against PD-1, PD-L1 and CTLA-4. 'IO' is industry shorthand; 'chemo-IO' means chemotherapy plus a checkpoint inhibitor, the commonest first-line...Open in Atlas Source
Immunogenic cell death: Immunogenic cell death is a way of dying that alerts the immune system, unlike quiet apoptosis.Open in Atlas Source
Immunoglobulin replacement after CAR-T, bispecifics and long anti-CD20 treatment: Treatments that remove B cells also remove the antibodies B cells make, and some people never make them again. When repeated chest and sinus infections follow, donated antibody given monthly by drip or weekly under the skin prevents them.Open in Atlas Source
Immunohistochemistry (IHC): Staining a tissue slice with antibodies so a protein shows up in colour under the microscope.Open in Atlas Source
Immunomodulatory drugs (IMiDs) and CELMoDs: Thalidomide and its descendants lenalidomide and pomalidomide, which hijack a cellular waste-disposal tag (cereblon) to destroy two proteins myeloma cells depend on, while also revving up T and NK cells. CELMoDs such as iberdomide and mezigdomide bind cereb...Open in Atlas Source
Immunonutrition: Immunonutrition means nutritional drinks enriched with specific nutrients (arginine, omega-3 fats, nucleotides) meant to strengthen immune function, mostly given before major surgery.Open in Atlas Source
Immunoscore: The Immunoscore counts the immune cells inside a bowel tumour and at its invading edge and turns the density into a single score. People with a high score relapse far less often than people with a low one, whatever their stage, and the score adds informatio...Open in Atlas Source
Immunotherapy: Any treatment that works by getting the patient's own immune system to attack the cancer, rather than attacking the cancer directly. It can produce responses that last for years, but only in some patients.Open in Atlas Source
Immunotherapy response and its prediction: Immunotherapy response means whether a patient's cancer shrinks or stays controlled when the immune system is unleashed; predicting who will respond is one of the hardest open problems in cancer AI.Open in Atlas Source
IMRT / IGRT / VMAT (modern external beam radiotherapy): Radiation beams shaped and varied in intensity from multiple angles, or while the machine rotates around the patient (VMAT), so the dose hugs the tumour and misses healthy tissue, checked against imaging before each session so it lands where planned. It cut...Open in Atlas Source
In situ: Latin for 'in place': abnormal cells that look like cancer but have not yet broken through the layer they started in. Stage 0. Not yet able to spread, and usually curable by removing it.Open in Atlas Source
In vitro and in vivo: In vitro means 'in glass': experiments on cells or molecules in a dish. In vivo means 'in the living': experiments in animals or people. A drug that kills cancer cells in vitro has cleared only the first and easiest hurdle.Open in Atlas Source
Incidence versus prevalence: Incidence is how many new cases occur in a year; prevalence is how many people are living with the disease at a given moment. A curable or fast-killing cancer can have high incidence but low prevalence.Open in Atlas Source
India New Drugs and Clinical Trials Rules 2019: India's 2019 rules for approving new drugs and running trials set deadlines for the regulator, fixed compensation for trial injuries, and allowed waivers of local trials for drugs already approved abroad, a waiver widened in 2024 for cancer and orphan drugs.Open in Atlas Source
Indication withdrawal: When a drug's approval for a particular cancer is cancelled, usually because the confirmatory trial failed to show benefit, sometimes because of safety. The drug may stay on the market for its other uses, and occasionally an indication is later re-approved...Open in Atlas Source
Indolent and aggressive lymphoma: Lymphomas are split by how fast they grow, and the split decides what happens next. Aggressive lymphomas grow over weeks, are treated at once and are often cured. Indolent lymphomas grow over years, are often watched rather than treated, and are usually con...Open in Atlas Source
Induction therapy: The first, most intensive block of treatment, intended to knock the cancer into remission. In leukaemia it is the hospital stay that clears the marrow; in solid tumours it is chemotherapy given before definitive local treatment.Open in Atlas Source
Infection prophylaxis in lymphoma: PJP, herpes, fungal risk and vaccination: Several lymphoma treatments knock out the part of the immune system that keeps a particular lung infection, Pneumocystis, at bay. A low-dose antibiotic three times a week prevents it, and a separate tablet prevents shingles.Open in Atlas Source
Inflammation: The body's response to injury or infection: immune cells and fluid rush in, causing redness, heat and swelling. Short bursts heal; long-term smouldering inflammation promotes cancer.Open in Atlas Source
Inflation Reduction Act 2022: Medicare drug price negotiation: The 2022 US law that for the first time lets Medicare negotiate prices for top-selling drugs, capped what older patients pay for prescriptions at 2,000 dollars a year, and exempted drugs approved only for rare diseases, an exemption widened in 2025.Open in Atlas Source
Informed consent: Informed consent is the conversation and the signed form in which a person learns what a trial involves, what might go wrong, what the alternatives are and that they can leave at any time, and then freely agrees to take part.Open in Atlas Source
Infusion reactions, hypersensitivity and extravasation: Reactions around the moment a drug is given: chills, fever or breathlessness from antibodies (infusion reactions), true allergy (hypersensitivity, rarely anaphylaxis), and leakage of a damaging drug into tissue around the vein (extravasation).Open in Atlas Source
Inherited syndromes that cause skin cancer: Gorlin syndrome and xeroderma pigmentosum: Two rare inherited conditions cause skin cancer decades earlier and in far greater numbers than sun exposure alone. Gorlin syndrome causes many basal cell carcinomas from a young age through a fault in the same pathway the hedgehog inhibitor drugs block. Xe...Open in Atlas Source
Inhibitor: A drug that blocks a specific protein from doing its job, usually by lodging in the pocket the protein needs to work. Most targeted cancer drugs are named after what they inhibit.Open in Atlas Source
Innovative Medicines Fund (England): A fund launched in 2022 that does for non-cancer medicines what the Cancer Drugs Fund does for cancer: pays for a promising but uncertain drug for a limited period while evidence is gathered, with the same budget of 340 million pounds.Open in Atlas Source
INRG staging and risk groups: INRG staging is the international system that sorts neuroblastoma into four risk groups, from the lowest (often observed, sometimes regressing on its own) to high risk (about half of patients), using age under 18 months, spread, MYCN amplification, 11q stat...Open in Atlas Source
Intention-to-treat (ITT) and per-protocol analysis: Analysing every patient in the group they were randomised to, whether or not they actually took the treatment. It preserves the fairness of randomisation and reflects what happens when a treatment is prescribed in real life; per-protocol analysis, by contra...Open in Atlas Source
Interferon-gamma gene signature (T-cell-inflamed signature): An interferon-gamma signature is a readout of a handful of genes that T cells switch on when they are already inside a tumour and fighting; tumours with a high score respond to PD-1 drugs more often across many cancer types, but the score is not yet reliabl...Open in Atlas Source
Interim analysis, readout and data cut-off: A trial's results are not one event but a series: pre-planned looks at the data (interim analyses) while it is still running, a data cut-off date that freezes the dataset for each look, a 'topline' announcement of the headline numbers, and a final analysis...Open in Atlas Source
Intermittent androgen deprivation (IAD): Taking planned breaks from hormone therapy once the PSA has settled, restarting when it rises again. The aim is to give a man time back with his energy, his libido and his mood. The largest trial found the benefit was real but lasted about three months, and...Open in Atlas Source
International Prognostic Index (IPI): A five-point score (age, stage, performance status, LDH, extranodal sites) that predicts how risky a lymphoma is before treatment.Open in Atlas Source
Interstitial lung disease (ILD) / pneumonitis: Interstitial lung disease (ILD) is lung inflammation, a serious side effect of some ADCs (especially Enhertu) and immunotherapy.Open in Atlas Source
Interval breast cancer (a cancer found between screening rounds): An interval breast cancer is one diagnosed after a normal screening mammogram and before the next invitation. Fast-growing cancers, triple-negative disease among them, make up a larger share of interval than of screen-detected cancers, which is why a new br...Open in Atlas Source
Interval cancer: An interval cancer is one diagnosed after a screening test or a colonoscopy that found nothing, and before the next test was due. Every screening programme has them. Counting them honestly is how a programme finds out what it is missing, and in the bowel mo...Open in Atlas Source
Intra-tumour heterogeneity: Cells within one tumour can differ in their genes, appearance and behaviour, so a single biopsy may not represent the whole cancer.Open in Atlas Source
Intracholecystic papillary-tubular neoplasm (ICPN): An ICPN is a raised, polyp-like growth of the gallbladder lining 1 cm or larger that can turn into cancer. It is the rarer route to gallbladder cancer, and the cancers that arise from it do better than those from flat dysplasia.Open in Atlas Source
Intraductal carcinoma of the prostate (IDC-P): Cancer cells filling prostate ducts and acini that still have their own outer basal cell layer. It is almost always found beside an invasive cancer, it marks a worse outlook, and on its own it is one of the reasons the NHS and the NCCN offer inherited-cance...Open in Atlas Source
Intrahepatic, perihilar, distal and gallbladder cancer: Bile duct cancers are named by where they start: inside the liver, at the hilum where the ducts join, in the lower duct near the pancreas, or in the gallbladder. Each behaves and mutates differently.Open in Atlas Source
Intraperitoneal (IP) chemotherapy: Delivering chemotherapy directly into the abdominal cavity through a catheter, so the tumour deposits on the lining get a far higher dose than the rest of the body would tolerate.Open in Atlas Source
Intrathecal therapy (lumbar puncture, Ommaya reservoir): Giving drugs directly into the fluid around the brain and spinal cord, by needle in the lower back or through a small reservoir under the scalp, because most drugs cannot cross from the blood into that space.Open in Atlas Source
Intravesical therapy (BCG and bladder instillations): Putting a drug directly into the bladder through a catheter and leaving it for an hour or two, so it treats the lining without going round the body. BCG, a weakened tuberculosis vaccine, has been the most effective such drug for 45 years.Open in Atlas Source
Invasive: Cancer that has grown through the boundary of the tissue it started in and into the surrounding tissue. This is the step that separates true cancer from in situ disease and gives it access to blood and lymph vessels.Open in Atlas Source
Invasive disease-free survival (iDFS): Invasive disease-free survival is the yardstick of most trials that treat early breast cancer after surgery. A patient counts as an event if the cancer comes back anywhere as invasive disease, a new invasive cancer appears in either breast or elsewhere, or...Open in Atlas Source
IPSET-thrombosis score (essential thrombocythaemia): Essential thrombocythaemia rarely shortens life, so treatment is about preventing clots: the IPSET-thrombosis score combines age over 60, a previous clot and the JAK2 mutation to sort patients into very low, low, intermediate and high risk, and only the hig...Open in Atlas Source
IPSS-R and IPSS-M (myelodysplastic syndrome risk scores): IPSS-R adds up marrow blasts, blood counts and chromosome findings, and IPSS-M adds the mutations in 31 genes, to place a person with myelodysplastic syndrome in a risk group that decides between watching, growth-factor and low-intensity drugs, or moving qu...Open in Atlas Source
IVDR (EU In Vitro Diagnostic Regulation 2017/746): Europe's rules for diagnostic tests, which since 2022 require most cancer tests to be certified by an independent body before they carry a CE mark, with deadlines for older tests running to 2029.Open in Atlas Source

J

JAK2 V617F: A single letter change in the JAK2 gene that jams the growth signal for blood cells in the on position. Almost everyone with polycythaemia vera has it, as do about half of those with essential thrombocythaemia or myelofibrosis.Open in Atlas Source
Japan conditional early approval and time-limited approval: Japan can approve a medicine for a serious disease on early data when a confirmatory trial would be hard to run, on condition that evidence is gathered after launch; for cell and tissue products a 2014 law allows a time-limited approval that must be confirm...Open in Atlas Source

K

Kaplan-Meier curve, censoring and proportional hazards: A Kaplan-Meier curve shows the share of patients still alive (or still free of progression) at each point in time; it steps down at each event and uses everyone's follow-up even if they have not had the event yet.Open in Atlas Source
Keratinocyte cancer (and why 'non-melanoma skin cancer' is being retired): The two commonest cancers in the world, basal cell carcinoma and cutaneous squamous cell carcinoma, both arise from keratinocytes, the cells that make up most of the outer layer of skin. They used to be lumped together as non-melanoma skin cancer, a name de...Open in Atlas Source
Keratoacanthoma: the tumour that may be a squamous cell carcinoma: A dome-shaped lump with a central plug of keratin that grows fast over a few weeks and may then shrink on its own. Whether it is a benign tumour or a squamous cell carcinoma that happens to regress has been argued for decades; the WHO treats it as a type of...Open in Atlas Source
Ki-67 in triple-negative breast cancer: Ki-67 is a stain that marks dividing cells. Triple-negative cancers almost all score high, typically around 60 percent, so the marker separates them from slower hormone-driven cancers but rarely changes treatment within the triple-negative group; the intern...Open in Atlas Source
Kinase: An enzyme that switches other proteins on by sticking a phosphate group onto them. Cancer signalling runs on kinases, and kinase inhibitors are the biggest class of targeted drugs.Open in Atlas Source
KRAS allelic imbalance and mutant KRAS dosage in pancreatic cancer: Beyond which KRAS mutation a pancreatic tumour carries, how many copies of the mutant allele it has matters: tumours that lose the normal copy or gain extra mutant copies behave more aggressively and lean towards the basal-like subtype, which is one reason...Open in Atlas Source
KRAS mutation subtypes (G12C, G12D, G12V): KRAS, the most commonly mutated cancer gene, comes in flavours named by the exact amino acid change. G12C (common in smokers' lung cancer) was the first to get a drug; G12D dominates pancreatic and colorectal cancer and its inhibitors are arriving now.Open in Atlas Source

L

Label, indication and label expansion: A drug's label is the official document stating exactly which patients (the indication) it is approved for, at what dose, with what warnings. Each new cancer, line of therapy or combination added to it is a label expansion, approved through a supplemental a...Open in Atlas Source
Landmark and milestone survival (5-year survival, median follow-up): The percentage of patients alive (or progression-free) at a fixed time point such as 2, 5 or 10 years, read off a Kaplan-Meier survival curve. With immunotherapy the 'tail of the curve', the fraction still alive years later, often matters more than the median.Open in Atlas Source
Laparoscopy (keyhole surgery): Operating or looking inside the abdomen through a few small holes with a camera, instead of one large incision.Open in Atlas Source
Late effects and survivorship toxicity: Health problems appearing months or decades after treatment ends: heart damage, infertility, second cancers, lymphoedema, dry mouth, memory problems, weak bones. They matter most for children and young adults, who live longest with them.Open in Atlas Source
Late effects of Hodgkin lymphoma treatment, and the follow-up that answers them: Hodgkin lymphoma is usually cured, and the problems that follow arrive twenty and thirty years later: heart disease, an underactive thyroid, and second cancers, especially breast cancer in women irradiated to the chest when young. Most of them can be watche...Open in Atlas Source
Late recurrence: Hormone-driven breast cancer can come back 10 or even 20 years after treatment, unlike most cancers, which is why hormone therapy lasts so long.Open in Atlas Source
Lauren classification (intestinal vs diffuse): Stomach cancers come in two main shapes: intestinal (gland-forming, linked to H. pylori and HER2) and diffuse (scattered cells, linked to CDH1 loss and worse outcomes).Open in Atlas Source
Lead time, and lead-time bias: Finding a cancer earlier means you know about it for longer, even if nothing you do changes the day you die. That extra stretch of knowing is called the lead time, and lead-time bias is the mistake of counting it as extra life. It is the single biggest reas...Open in Atlas Source
Leaving radiotherapy out: Radiotherapy after breast-conserving surgery halves the chance of the cancer coming back and prevents about one death in breast cancer for every four recurrences it prevents. In older women with small, hormone-sensitive, slow-growing tumours who will take e...Open in Atlas Source
Leptomeningeal disease: Cancer cells spreading in the fluid and membranes that bathe the brain and spinal cord, rather than as a solid lump. It causes headaches, nerve palsies and confusion and has been one of the hardest situations to treat.Open in Atlas Source
Lesion: A doctor's neutral word for any abnormal patch of tissue seen on a scan or examination: a lump, a nodule, a shadow. It may or may not be cancer until a biopsy says so.Open in Atlas Source
Leukaemia (tissue type): Cancer of the blood-forming cells in the bone marrow, which flood the blood with immature or abnormal white cells and crowd out normal blood production. It has no single lump to remove.Open in Atlas Source
Lewis-negative (Lewis antigen-negative, CA 19-9 non-secretor) status: About one person in ten to twenty cannot make the sugar that the CA 19-9 blood test measures, because they lack a working copy of the Lewis blood-group gene. In these Lewis-negative people the test stays low however large the cancer, so a normal CA 19-9 doe...Open in Atlas Source
LGR5: A marker of stem cells in the gut and of stem-like cells in tumours, used to aim drugs at the cells that regrow a cancer.Open in Atlas Source
Li-Fraumeni syndrome (germline TP53): Li-Fraumeni syndrome is an inherited fault in the TP53 gene giving a lifetime cancer risk near 100% in women and ~75% in men, with sarcomas, breast cancer, brain tumours, adrenal cancer and leukaemias often in childhood. Whole-body MRI surveillance saves li...Open in Atlas Source
LI-RADS (Liver Imaging Reporting and Data System): LI-RADS is the radiologist's grading of a liver nodule on contrast CT or MRI in a cirrhotic liver, from LR-1 (definitely benign) to LR-5 (definitely cancer); an LR-5 lesion is treated as hepatocellular carcinoma without a biopsy, which is why liver cancer i...Open in Atlas Source
Ligand: The molecule that fits into a receptor and switches it on: growth factors, hormones and cytokines are all ligands. Cancers make their own ligands or mutate receptors so none is needed, and some drugs act on the ligand itself, as bevacizumab does by soaking...Open in Atlas Source
Limb-salvage surgery: Removing a bone or soft-tissue sarcoma while keeping the arm or leg, rebuilding the bone with a metal endoprosthesis or a graft.Open in Atlas Source
Limited-stage vs extensive-stage (small-cell lung cancer): Small-cell lung cancer uses a two-way split instead of the usual four stages: limited (confined to one side of the chest and treatable within one radiation field, about a third of patients) or extensive (everything else).Open in Atlas Source
Linear energy transfer (LET): How densely a radiation track dumps energy along its path. Sparse tracks (X-rays, most of a proton beam) are easier to repair; dense tracks (the proton's stop-point, carbon ions, alpha particles) punch clustered holes in DNA.Open in Atlas Source
Linear probe: A linear probe is a simple linear model (logistic or ridge regression) trained on a frozen model's embeddings to test how much useful information those embeddings hold.Open in Atlas Source
Lines of therapy: First-line is the first treatment for advanced cancer; second-line is what comes after it fails, and so on.Open in Atlas Source
Linker (ADC): The linker is the chemical tether between antibody and payload. It must hold in the blood and let go inside the tumour.Open in Atlas Source
Liver-directed therapy (TACE, TARE, HAI, ablation): The set of treatments aimed only at tumours in the liver, delivered through its artery or by needle, used when the liver is the main or only site of disease: chemoembolisation, radioactive beads, ablation and infusion pumps.Open in Atlas Source
Liver-limited metastatic bowel cancer: Bowel cancer that has spread only to the liver, and sometimes only to the lung, is one of the few forms of secondary cancer treated with the aim of cure. If the deposits can be removed or destroyed, with chemotherapy before and after, a substantial minority...Open in Atlas Source
Living with a stoma after bowel cancer surgery: A colostomy or ileostomy after bowel cancer surgery may be temporary, to let a join heal, or permanent. Recovery takes about eight weeks, bags come as one-piece or two-piece and drainable or closed, permanent colostomy supplies are free on prescription, and...Open in Atlas Source
Living with an antibody-drug conjugate: diarrhoea, blood counts, eyes and lungs: The antibody-drug conjugates used in triple-negative breast cancer carry chemotherapy into the cancer but still cause chemotherapy-like effects: sacituzumab govitecan mainly low white cells and diarrhoea, datopotamab deruxtecan mouth soreness, eye problems...Open in Atlas Source
Living with an indolent lymphoma rather than being cured of one: Slow-growing lymphomas are usually controlled rather than cured: treatment works, the disease goes away for a while, and at some point it comes back and is treated again. Most people live with that pattern for many years, and it asks something different of...Open in Atlas Source
Living with FOLFIRINOX, NALIRIFOX and gemcitabine with nab-paclitaxel: The three main regimens share low blood counts, tiredness, sickness and sore mouth; FOLFIRINOX and NALIRIFOX add irinotecan diarrhoea and oxaliplatin's cold-triggered tingling and rare throat spasm, gemcitabine with nab-paclitaxel adds hair loss and neuropa...Open in Atlas Source
Living with FOLFOX, CAPOX, FOLFIRI and the EGFR antibodies: The bowel cancer regimens share low blood counts, tiredness, sickness and a sore mouth. Oxaliplatin adds cold-triggered tingling, irinotecan adds early and late diarrhoea, capecitabine adds hand-foot syndrome and needs a DPD test first, and cetuximab or pan...Open in Atlas Source
Living with jaundice and itching (biliary cancer): Jaundice from a blocked bile duct turns the skin and eyes yellow, darkens urine, pales stools and causes itching; relieving the blockage with a stent is the main treatment, and cool moisturiser, loose cotton clothes and prescribed medicines help the itch me...Open in Atlas Source
Lobectomy: Removing one lobe of the lung (the right lung has three, the left two). The standard operation for early lung cancer.Open in Atlas Source
Local-only language models over patient data (privacy by architecture): Running an open language model on the same machine as a patient's data, with code that blocks any network call, lets a system explain model outputs in words without the data ever leaving the room.Open in Atlas Source
Locally advanced and locoregional disease: Cancer that has grown beyond its organ into nearby tissue or lymph nodes but has not spread to distant sites. It is treated with the goal of cure but usually needs several treatments (surgery, radiotherapy, drugs) together.Open in Atlas Source
Logistic regression and nearest-centroid classifiers: Logistic regression is the plain linear classifier used as a baseline for subtype prediction; a nearest-centroid classifier instead assigns each sample to the subtype whose average profile it most resembles, which is how PAM50 works.Open in Atlas Source
Loss functions: cross-entropy and mean squared error: A loss function is the number training tries to make small: cross-entropy for classification (how surprised the model was by the true class) and mean squared error for regression and reconstruction (how far off the predicted values were).Open in Atlas Source
Lost in Transition: the 2006 report that defined survivorship care, and the care plan it invented: The 2006 Institute of Medicine report defined survivorship care, made ten recommendations, and invented the survivorship care plan. The plan became an accreditation standard, and then the randomised trials of it were negative.Open in Atlas Source
Low anterior resection syndrome (LARS): The group of bowel problems that can follow sphincter-preserving surgery for rectal cancer: going more often, urgency with or without leaking, feeling the bowel is not empty, passing small amounts little and often, and not being able to tell wind from stool...Open in Atlas Source
Low antibodies and infection risk for years after anti-CD20 and bispecific antibodies: Treatments that remove B cells also remove the cells that make antibodies, and the effect can last for years after the last dose. Most people need nothing more than ordinary vigilance, but some need preventive antibiotics or infusions of donor antibodies, a...Open in Atlas Source
Low-grade serous ovarian cancer (LGSOC): Low-grade serous ovarian cancer is a slow-growing, RAS-driven type of ovarian cancer that resists chemotherapy but responds to hormone blockers and MEK-pathway drugs.Open in Atlas Source
Low-risk differentiated thyroid cancer (ATA risk): Small thyroid cancers confined to the gland with no spread. They are almost always cured by surgery alone and no longer need radioactive iodine.Open in Atlas Source
Lugano classification / Ann Arbor staging: The Lugano classification is the lymphoma staging system: stage I to IV by how many lymph node regions and organs are involved, with PET-based response criteria.Open in Atlas Source
Luminal androgen receptor (LAR) subtype: Luminal androgen receptor is one of the four molecular subtypes of triple-negative breast cancer. Its cells look and behave like hormone-driven luminal cells but run on the androgen receptor instead of oestrogen, which makes them slower growing, less respon...Open in Atlas Source
Lumpectomy (breast-conserving surgery): Removing only the tumour with a rim of normal breast, keeping the breast; almost always followed by radiotherapy.Open in Atlas Source
Lung cancer after chest radiotherapy and after alkylating chemotherapy: Lung cancer is the commonest cause of death among people who develop a second cancer, and chest radiotherapy raises the risk of it for more than twenty years. There is no screening programme aimed at survivors anywhere, although some survivor groups have a...Open in Atlas Source
Lung cancer drugs in England: what NICE has recommended: Which lung cancer drugs the NHS in England funds, and which it does not. Every reference number below was opened on the NICE website in September 2026 and its recommendation read.Open in Atlas Source
Lung cancer in never-smokers: Lung cancer in someone who has never smoked. About 15 percent of UK lung cancers and 15 to 25 percent worldwide. It is usually adenocarcinoma, commoner in women, more likely to carry a mutation a drug can target, and invisible to every screening rule, becau...Open in Atlas Source
Lung cancer trials open today (registry snapshot): Every phase 2 or 3 interventional trial that was recruiting, about to open or still running for lung cancer on ClinicalTrials.gov in September 2026, with the hospitals in the United Kingdom that take part named where the registry lists them.Open in Atlas Source
Lung cancer: the failed and stopped programmes, and why: The list of lung cancer treatments that looked right and did not work: more radiotherapy, radiotherapy after surgery for involved nodes, immunotherapy at the wrong PD-L1 threshold, immunotherapy added to chemoradiotherapy, and several drugs whose confirmato...Open in Atlas Source
Lung-RADS and nodule reporting: The scoring systems that turn a screening CT into an action. Each nodule gets a category from the scan, and the category dictates the next step: rescan in a year, rescan in three months, or go to a lung cancer clinic. They exist so that the same scan gets t...Open in Atlas Source
Lymph node: Small bean-shaped filters along the lymph vessels where immune cells gather. They are often the first place a cancer spreads, so surgeons check them to see how far the disease has gone.Open in Atlas Source
Lymph node status (node-positive / node-negative): Whether the cancer has reached the nearby lymph nodes, the filters along the lymphatic drainage. It is the single strongest predictor of whether cancer has escaped the organ, and it drives most decisions about extra treatment after surgery.Open in Atlas Source
Lymphadenectomy (lymph node dissection): Surgically removing the lymph nodes that drain a tumour, both to stage the cancer and to clear any spread.Open in Atlas Source
LymphGen and the genetic clusters of large B-cell lymphoma: Sequencing shows that large B-cell lymphoma is at least seven diseases, each defined by which faults occur together. The classification explains a great deal about how the disease behaves and currently changes almost nothing about how it is treated.Open in Atlas Source
Lymphodepletion before CAR-T: A short course of chemotherapy (usually fludarabine and cyclophosphamide) given in the days before a CAR-T infusion to clear out the patient's own lymphocytes, making room and growth signals for the engineered cells to expand.Open in Atlas Source
Lymphoedema after breast cancer treatment: Swelling of the arm, hand or breast that happens when lymph fluid cannot drain because the lymph nodes have been removed or irradiated. It is permanent once established, it can appear years later, and it is the main reason surgeons now take one or two lymph...Open in Atlas Source
Lymphoedema after breast cancer treatment: Swelling of the arm, hand, breast or chest wall caused by lymph fluid that can no longer drain, after the lymph nodes under the arm have been removed or irradiated. It can start months or years later, it is controlled rather than cured, and the earlier it i...Open in Atlas Source
Lymphoma (tissue type): Cancer of lymphocytes, the white blood cells of the immune system, usually growing as masses in lymph nodes, spleen or other organs. It is divided into Hodgkin lymphoma and the non-Hodgkin lymphomas, most of which arise from B cells and keep surface markers...Open in Atlas Source
Lymphoma treatments that did not work: the negative trials worth knowing: A list of things that were expected to improve lymphoma treatment and did not. Knowing them is how a patient can tell a reasonable suggestion from an outdated one.Open in Atlas Source
Lymphovascular invasion (LVI): The pathologist has seen cancer cells inside small lymph or blood vessels in the removed tissue: a sign the tumour has found the exit routes, even if the nodes are clear.Open in Atlas Source
Lynch syndrome: Lynch syndrome is the most common inherited cancer syndrome: a faulty mismatch-repair gene raises lifetime bowel cancer risk to 40-80% and also endometrial and other cancers.Open in Atlas Source
Lynch syndrome testing after bowel cancer, and what it means for the family: Every bowel cancer should be tested for mismatch repair loss, and where it is found, for whether that loss is inherited. A Lynch syndrome result changes your treatment options, gives each of your children and siblings a one in two chance of carrying it, and...Open in Atlas Source

M

M-protein, immunofixation and serum free light chains: Myeloma cells are clones of one antibody-making cell, so they pour a single identical antibody, the M-protein, into the blood; measuring it (and the free light chains that go with it) is how myeloma is diagnosed, how deep a response is judged, and how relap...Open in Atlas Source
Macrophage: Large immune cells that engulf debris, microbes and dead cells and coordinate inflammation. Tumours recruit and retrain them: tumour-associated macrophages can make up half the cells in some tumours, where they feed blood-vessel growth and suppress T cells,...Open in Atlas Source
Magnification (20x, 40x) and microns per pixel: Slides are scanned at 20x or 40x objective magnification, about 0.5 or 0.25 microns per pixel; a model trained at one scale can misread tissue at another.Open in Atlas Source
Maintenance and consolidation in lymphoma: where it works and where it does not: After the main treatment, some lymphomas are given a lower-intensity drug for months or years to hold the remission. It lengthens remission in follicular and mantle cell lymphoma but has never been shown to lengthen life, so it is a trade against two years...Open in Atlas Source
Maintenance therapy: Ongoing, gentler treatment given after the main course has shrunk the cancer, to hold it in check for as long as possible rather than to shrink it further.Open in Atlas Source
Major pathological response (MPR): When, after pre-surgery treatment, the removed tumour contains little or no living cancer: 10% or less viable cells.Open in Atlas Source
Maleimidocaproyl (mc), non-cleavable: The non-cleavable maleimidocaproyl (mc) linker is a tether with no cleavage site: the payload is released only when the antibody is fully digested.Open in Atlas Source
Malignant pleural effusion: Fluid collecting in the space between the lung and the chest wall because cancer has reached the lining. It makes people breathless, it comes back after it is drained, and the decision is not whether to drain it but how to stop it returning.Open in Atlas Source
Malignant pleural effusion and ascites: Fluid that builds up around the lung (pleural effusion) or in the abdomen (ascites) because cancer cells irritate the lining and block lymph drainage; it causes breathlessness or a swollen, tight belly.Open in Atlas Source
Malnutrition screening tools (MUST, NRS-2002, MST, PG-SGA): Quick questionnaires that flag who is at risk of malnutrition: recent weight loss, low BMI, poor appetite, illness severity. Anyone flagged should see a dietitian.Open in Atlas Source
Margins after breast-conserving surgery, and second operations: After conserving surgery a pathologist measures how close the cancer came to the edge of the tissue removed. Cancer at the inked edge means another operation is offered; within 1 mm it is considered; and the threshold was lowered in 2024 specifically to spa...Open in Atlas Source
Masked autoencoders and masked gene modelling: A masked autoencoder hides a random part of the input (image patches, or half the genes in a profile) and learns to reconstruct it from the rest.Open in Atlas Source
Mastectomy: Removing the whole breast, either for cancer or preventively in BRCA1/2 carriers, where bilateral risk-reducing mastectomy cuts breast cancer risk by 90% or more. For most early cancers, lumpectomy plus radiotherapy works as well, so mastectomy is chosen fo...Open in Atlas Source
Master protocol (platform, basket and umbrella trials): A master protocol is one trial framework that tests several treatments, several cancers or both under a single set of rules, so new drugs can join and leave without a new trial being built each time. Platform trials add and drop arms over the years, basket...Open in Atlas Source
Maximum tolerated dose (MTD): The highest dose of a drug at which about a third of patients or fewer have dose-limiting side effects, the traditional target of phase 1 trials. For chemotherapy more was better; targeted drugs and antibodies often saturate their target far below it, which...Open in Atlas Source
mc-Val-Cit-PABC: The mc-Val-Cit-PABC linker is the workhorse of the vedotin ADCs: a valine-citrulline dipeptide cut by cathepsin B, releasing MMAE with a bystander effect.Open in Atlas Source
mCODE (minimal Common Oncology Data Elements): A standard checklist of cancer data every electronic record should capture the same way, so data can flow between hospitals, registries, and research.Open in Atlas Source
mCRPC and mHSPC (castration-resistant vs hormone-sensitive prostate cancer): Prostate cancer starts out fed by testosterone (hormone-sensitive) and shrinks when it is removed. When it learns to grow despite castrate testosterone levels it is called castration-resistant, a later and more dangerous stage with its own treatments.Open in Atlas Source
Mechanical theory: stiffness, pressure and force as causes: Cancer cells feel their surroundings. A stiff, dense matrix or a compressed tissue is not just a symptom but a signal that pushes cells towards malignancy, and pressure inside tumours squeezes vessels shut so drugs and oxygen cannot get in. Bissell and Weav...Open in Atlas Source
Mechanism-of-action recovery and known-biology probes: A model that claims to have learned biology should, without being told, point at the known mechanism of a known drug or the known marker of a known cell type; recovering such known biology is an orthogonal check that a correlation is not an artefact.Open in Atlas Source
Median survival: The time by which half the patients in a group have died (or, for other endpoints, progressed). It is the midpoint of a spread, not a prediction for anyone: half live longer, some much longer.Open in Atlas Source
Mediastinal lymph node stations: The lymph nodes in the chest are numbered by position on an agreed map, so that a scan, a needle biopsy and an operation in different hospitals all mean the same thing. Which numbered stations contain cancer decides the N category and therefore whether surg...Open in Atlas Source
Mediastinum: The space in the middle of the chest between the two lungs, containing the heart, great vessels, windpipe, food pipe and the lymph nodes that lung cancer spreads to first.Open in Atlas Source
Medicare coverage with evidence development: Medicare's way of paying for a promising but uncertain test or treatment only for patients enrolled in a registry or study, used for PET scans in cancer from 2006 and now the frame for how Medicare covers gene panels and cell therapies.Open in Atlas Source
Medicines and Medical Devices Act 2021: The 2021 UK law, passed after Brexit, that gives ministers power to rewrite the rules for licensing medicines, running trials and regulating devices without new primary legislation, and that created a patient safety commissioner.Open in Atlas Source
Medulloblastoma molecular groups (WNT, SHH, group 3, group 4): Medulloblastoma is four diseases under one microscope: the WNT group is almost always cured, the SHH group depends on age and TP53, and groups 3 and 4 carry most of the deaths, so the group now steers how much radiation and chemotherapy a child receives.Open in Atlas Source
MEN1 and hereditary neuroendocrine syndromes: Inherited conditions (MEN1, VHL, NF1, tuberous sclerosis) that cause neuroendocrine tumours, often multiple and at a young age, so families need genetic testing and surveillance.Open in Atlas Source
Menopause symptoms after chemotherapy for breast cancer: Chemotherapy can stop the ovaries working, temporarily or for good; hot flushes, sweats, poor sleep, low mood and vaginal dryness follow, and because HRT is not routinely offered after breast cancer the usual answers are non-hormonal medicines, vaginal mois...Open in Atlas Source
Merkel cell polyomavirus (MCPyV) status: About eight in ten Merkel cell carcinomas are driven by a common skin virus that has stitched itself into the tumour's DNA; the virus-negative rest are driven by sunlight and carry a huge mutation load. Both respond to immunotherapy, and in virus-positive p...Open in Atlas Source
MET amplification (bypass resistance): When lung cancer switches on the MET receptor to bypass a blocked EGFR pill.Open in Atlas Source
MET exon 14 skipping mutation: A splice-site mutation that makes cells skip exon 14 of the MET gene removes the receptor's off switch, so MET piles up on the cell surface; found in about 3 percent of lung adenocarcinomas, typically in older smokers or never-smokers, it is targeted by the...Open in Atlas Source
MET-hours per week: The unit used to measure how much exercise someone does. One MET is the energy of sitting quietly; brisk walking is about 4 METs, so 45 minutes of brisk walking is 3 MET-hours. Guidelines aim for around 10 MET-hours a week.Open in Atlas Source
Metabolic syndrome and insulin resistance: Metabolic syndrome is a cluster of central obesity, high blood pressure, high blood sugar and abnormal blood fats. It raises the risk of several cancers and worsens outcomes after diagnosis, largely through high insulin levels.Open in Atlas Source
Metabolic theory of cancer: from Warburg to oncometabolites: Otto Warburg noticed a century ago that cancer cells ferment glucose even when oxygen is plentiful and concluded that damaged respiration causes cancer. The observation held and became the basis of PET scanning, but the causal claim did not: most cancers re...Open in Atlas Source
Metaplasia, dysplasia, carcinoma in situ: the flat route to gallbladder cancer: Most gallbladder cancers grow out of flat, invisible changes in the lining: years of irritation from stones turn the mucosa metaplastic, then dysplastic, then into carcinoma in situ, and finally into invasive cancer, a process estimated at 10 to 15 years.Open in Atlas Source
Metastasis: Cancer that has spread from where it started to distant parts of the body, travelling through the blood or lymph. Metastasis is why staging scans look at the whole body, and the setting in which most new cancer drugs are approved first.Open in Atlas Source
Metastasis-free survival (MFS): The time from joining a trial until a scan first shows the cancer has spread, or the man dies, whichever comes first. It is the endpoint that got three hormone drugs licensed for prostate cancer that had not yet spread, because waiting for deaths would have...Open in Atlas Source
Metastatic spinal cord compression (MSCC): Cancer in or near the spine pressing on the spinal cord: an emergency, because delay makes the damage permanent.Open in Atlas Source
MGMT promoter methylation: A chemical switch that turns off a DNA-repair gene. When it is off, temozolomide works much better.Open in Atlas Source
MIBG Curie and SIOPEN scores: Neuroblastoma soaks up MIBG, a radioactive cousin of noradrenaline; the Curie and SIOPEN scores count how many body regions still light up on the scan, and a score that has not fallen enough after the first rounds of chemotherapy marks a child who is unlike...Open in Atlas Source
Microarray expression data: Microarrays measured gene expression by hybridising labelled RNA to spots of known DNA on a chip; they preceded RNA sequencing and still hold the longest-followed cohorts.Open in Atlas Source
Microenvironment and inflammation: tumours as wounds that do not heal: A tumour is not a lump of cancer cells but a tissue: fibroblasts, vessels and immune cells, recruited by the signals a wound uses and never told to stop. Virchow saw white cells in tumours in 1863; Dvorak called tumours 'wounds that do not heal' in 1986. It...Open in Atlas Source
Microsatellite instability (MSI-H) / mismatch repair deficiency (dMMR): Microsatellite instability is the mark of a broken DNA spell-checker (loss of MLH1, MSH2, MSH6 or PMS2) that leaves thousands of mutations, so the tumour displays abnormal proteins that T cells can recognise. It is found in a fraction of colorectal and endo...Open in Atlas Source
Microsatellite-stable (MSS) / mismatch-repair proficient (pMMR): The 'normal' result on the mismatch-repair test: the tumour has intact DNA spell-checking and few mutations. It describes about 95% of metastatic colorectal cancers and means checkpoint inhibitors alone are unlikely to work.Open in Atlas Source
Microwave ablation (MWA): Like radiofrequency ablation but using microwaves, which heat faster and larger volumes and are less affected by nearby blood vessels.Open in Atlas Source
Minimal / molecular residual disease (MRD): Cancer still present after treatment but too small to see on scans, detected by blood or marrow tests.Open in Atlas Source
Minimally invasive surgery (laparoscopic, robotic, VATS): Any operation done through small incisions with cameras and long instruments, including robot-assisted surgery; the cancer operation is the same, the wound is smaller.Open in Atlas Source
MIPI (Mantle Cell Lymphoma International Prognostic Index): MIPI turns age, performance status, LDH and white cell count into a low, intermediate or high-risk label for mantle cell lymphoma, and adding Ki-67 (MIPI-c) or TP53 status sharpens it; high-risk and TP53-mutated disease is where chemotherapy alone fails and...Open in Atlas Source
MLH1 promoter methylation (sporadic versus Lynch mismatch repair loss): When a tumour has lost the MLH1 mismatch-repair protein, a methylation test on the tumour tells the two causes apart: methylation switching the gene off means a sporadic cancer, no methylation means an inherited Lynch syndrome mutation is likely and the who...Open in Atlas Source
MMAE: MMAE is the tubulin-blocking payload in brentuximab, enfortumab, polatuzumab and tisotumab vedotin, four approved ADCs: it halts cell division and, being membrane permeable, leaks into neighbouring tumour cells. Nerve damage and low neutrophil counts are it...Open in Atlas Source
MMAF: MMAF is a charged cousin of MMAE that cannot cross membranes, so it kills only the targeted cell and spares neighbours. Eye side effects are characteristic.Open in Atlas Source
Model cards and datasheets for datasets: A model card is a short standard document shipped with a model stating what it was trained on, how it was evaluated, its intended use and its known failures; a datasheet does the same for a dataset.Open in Atlas Source
Model organism: A species studied in the lab to understand biology that is shared with humans: mice above all, plus zebrafish, flies, worms and yeast. Mice carrying human tumours are the standard test bed for cancer drugs, and a notoriously imperfect one.Open in Atlas Source
Mohs surgery: Skin cancer surgery in which the tumour is removed in thin layers, each checked under the microscope on the spot, until the edges are clear; it spares the most normal skin.Open in Atlas Source
Molecular response (MMR, MR4, treatment-free remission): In chronic myeloid leukaemia, how far the leukaemia gene signal in the blood has fallen, measured in logs: a 1,000-fold drop is a major molecular response, a 10,000-fold drop (MR4) is 'deep'. Deep responses held for two years let some patients stop their pi...Open in Atlas Source
Mondo disease ontology: Mondo is a unified disease ontology that merges the disease vocabularies (OMIM, Orphanet, NCIt, ICD and others) into one hierarchy with cross-references, so a disease named in one system can be found in the others.Open in Atlas Source
Monoclonal: Made from a single clone of cells, so every antibody molecule in the vial is identical and binds exactly the same spot. All therapeutic antibodies are monoclonal.Open in Atlas Source
Mortality: The number of deaths from a disease in a population per year. Cancer mortality has fallen about a third since 1991 in the US, mostly from less smoking, earlier detection and better treatment.Open in Atlas Source
MPN driver mutations (JAK2 V617F, CALR, MPL) and allele burden: Almost every polycythaemia vera and most essential thrombocythaemia and myelofibrosis carry one of three mutations (JAK2 V617F, CALR or MPL) that jam the growth signal on; finding one confirms the diagnosis is a true blood cancer rather than a reaction to s...Open in Atlas Source
MRD negativity (myeloma, 10⁻⁵ / 10⁻⁶): MRD negativity means no detectable myeloma cell among 100,000 or a million marrow cells. It is the best predictor of long survival and, since 2024, an accepted endpoint for accelerated approval.Open in Atlas Source
MRD-negative complete remission: MRD-negative complete remission means not just no leukaemia visible under the microscope, but none detectable with tests a thousand times more sensitive. It is the goal of modern leukaemia treatment.Open in Atlas Source
mRNA to protein concordance: mRNA to protein concordance is how well the amount of a gene's messenger RNA tracks the amount of the protein it codes for; for many genes it tracks poorly.Open in Atlas Source
Mucositis and stomatitis: Painful inflammation and ulcers of the mouth and gut lining, because chemotherapy and radiotherapy hit the fast-dividing cells that renew it. It affects most patients on head and neck chemoradiation or transplant conditioning, can make eating impossible, an...Open in Atlas Source
Multimodal fusion (early, late, modality dropout): Multimodal fusion combines several kinds of data about one patient (slides, expression, mutations, clinical variables) in one model; modality dropout randomly hides modalities during training so the model still works when some are missing.Open in Atlas Source
Mutation: A change in the DNA sequence, like a typo in a recipe. Most are harmless; a few change a protein in a way that helps a cell grow out of control.Open in Atlas Source
Mutational signature: A characteristic pattern of mutations that reveals what caused them: tobacco, UV, a broken repair gene.Open in Atlas Source
MutSig (significantly mutated gene detection): MutSig asks which genes are mutated more often than the background mutation rate would predict, separating likely drivers from long or late-replicating genes that collect passengers.Open in Atlas Source
MYCN amplification: Extra copies of the MYCN oncogene, found in about 20% of neuroblastomas, mark the most aggressive disease and define high risk at any age.Open in Atlas Source
MYD88 L265P and CXCR4 mutations: One letter change in MYD88 (L265P) keeps a B-cell survival signal permanently on; it is found in more than nine in ten Waldenström's macroglobulinaemia, most primary CNS and testicular lymphomas and a poor-risk group of DLBCL, and it predicts that BTK inhib...Open in Atlas Source
Myeloid-derived suppressor cells (MDSCs): Immature immune cells that tumours summon to switch off T cells. Their numbers in blood predict worse immunotherapy outcomes.Open in Atlas Source

N

N-of-1 trial: An N-of-1 trial is a randomised experiment in a single patient: the person alternates between treatment and comparison in random order, often blinded, to find out what works for them rather than for the average patient.Open in Atlas Source
NCCN Compendium and drug compendia: Lists of recommended off-label and on-label drug uses that US insurers, including Medicare, use to decide what to pay for.Open in Atlas Source
NCI Thesaurus (NCIt): The NCI Thesaurus is the US National Cancer Institute's reference vocabulary of diseases, drugs, anatomy and findings, each with a stable code such as C4872 for breast carcinoma.Open in Atlas Source
Necrosis: Messy, uncontrolled cell death, where the cell bursts and spills its contents. In tumours it usually means cells have outgrown their blood supply and starved.Open in Atlas Source
Neoadjuvant / adjuvant / perioperative: Neoadjuvant therapy is treatment given before surgery, adjuvant therapy is treatment given after it, and perioperative therapy is both. Neoadjuvant treatment shrinks tumours and shows whether the drug works in the living patient; adjuvant treatment aims to...Open in Atlas Source
Neoadjuvant therapy versus surgery first for resectable and borderline resectable pancreatic cancer: For pancreatic cancers that look removable, doctors debate whether to operate at once and give chemotherapy afterwards, or to give chemotherapy first. Trials show chemotherapy first helps when the tumour is borderline, touching the big vessels, but it is no...Open in Atlas Source
Neoantigen: A protein fragment created by a tumour mutation that the immune system has never seen before, so it can attack it without harming normal cells.Open in Atlas Source
Nephrectomy: Removing a kidney (radical) or just the tumour-bearing part of it (partial).Open in Atlas Source
Neuroendocrine differentiation in prostate cancer: Prostate cancer cells that have taken on the look and the markers of nerve-and-hormone cells. A trace of it is present in almost every prostate cancer and means nothing; a tumour made mostly of it is a different and much more serious disease, and it usually...Open in Atlas Source
Neuroendocrine tumour grade (Ki-67) and WHO classification: How fast the tumour cells are dividing, measured by Ki-67 staining, separates slow-growing neuroendocrine tumours from aggressive neuroendocrine carcinomas and decides the treatment.Open in Atlas Source
Neutropenia: A shortage of neutrophils, the white blood cells that fight bacteria, caused by chemotherapy hitting the bone marrow. It usually bottoms out (the nadir) 7-14 days after each cycle and recovers before the next; while low, infection risk is high.Open in Atlas Source
Neutropenic sepsis: the temperature rule and the 999 signs: During chemotherapy a temperature over 37.5 C or below 36 C, shivering, or feeling unwell even with a normal temperature means ringing the hospital's 24-hour line straight away; breathing very fast, confusion, mottled skin or no urine in a day means 999.Open in Atlas Source
New-onset diabetes as a signal of pancreatic cancer (and the ENDPAC score): A pancreatic cancer can cause diabetes before any other symptom, so new diabetes after the age of 50, especially with weight loss rather than weight gain, is a recognised warning sign. About one in a hundred such people is found to have pancreatic cancer wi...Open in Atlas Source
Nexavar compulsory licence (India, 2012): In March 2012 India's patent office let Natco make a generic of Bayer's kidney and liver cancer drug sorafenib at about 3 percent of the branded price, paying a royalty, because Bayer had priced it beyond most Indians' reach; it remains the leading example...Open in Atlas Source
Next-generation sequencing (NGS): Reading millions of DNA fragments in parallel, the engine behind every modern genomic test.Open in Atlas Source
NHS bowel cancer screening programme: The NHS posts a home test for hidden blood in the poo to everyone aged 50 to 74 in England every two years. Most people are told no further tests are needed; if blood is found they are offered a colonoscopy. It is the only NHS cancer screening programme tha...Open in Atlas Source
NICE technology appraisal methods (2022): The rulebook NICE uses to decide whether the NHS in England should pay for a medicine: a cost per quality-adjusted life year usually between 20,000 and 30,000 pounds, with extra weight since 2022 for severe diseases in place of the old bonus for end-of-life...Open in Atlas Source
NK cell: Natural killer cells: fast-acting immune cells that destroy abnormal cells without needing to be trained on a specific target. They specialise in killing cells that have hidden themselves from T cells.Open in Atlas Source
No specific molecular profile (NSMP) endometrial cancer: NSMP is the label an endometrial cancer gets when the three positive tests are all negative: no POLE mutation, intact mismatch repair and normal p53. It is the largest group, mostly hormone-driven and low grade, and it is treated by stage, grade and oestrog...Open in Atlas Source
Nodal and extranodal lymphoma: A lymphoma that starts in a lymph node is called nodal; one that starts in an organ is called extranodal. A substantial minority of non-Hodgkin lymphomas start outside the lymph nodes, and where it started often changes the cause, the treatment and the outl...Open in Atlas Source
Non-inferiority margin and equivalence trials: The margin is the amount of benefit a trial is allowed to lose and still call the new treatment good enough; it is chosen before the trial starts, and where it is set decides what the result means.Open in Atlas Source
Non-inferiority trial: A trial designed to show a new treatment is not meaningfully worse than the standard, rather than better: used when the new option is shorter, cheaper, less toxic or easier (five radiotherapy fractions instead of 25, six months of trastuzumab instead of twe...Open in Atlas Source
Non-muscle-invasive vs muscle-invasive bladder cancer (NMIBC / MIBC): Bladder cancer is divided by whether it has grown into the bladder's muscle wall. Before that, it is treated inside the bladder; after, the bladder is usually removed or irradiated.Open in Atlas Source
Nottingham grade (breast cancer grade 1, 2 and 3): The grade on a breast report is a sum of three scores: how much of the tumour still forms tubes, how ugly its nuclei are, and how many cells are caught dividing. Each is scored 1 to 3, and the total of 3 to 9 becomes grade 1, 2 or 3. Grade says how the canc...Open in Atlas Source
Nottingham Prognostic Index (NPI), and PREDICT: One number that puts a breast cancer's size, its node status and its grade together, because the stage on its own leaves grade out. Score under 2.4 is the excellent group; 5.4 or above is the poor group. PREDICT is the modern web tool that does the same job...Open in Atlas Source
Novartis v. Union of India (Glivec, 2013): In April 2013 India's Supreme Court refused Novartis a patent on the crystal form of imatinib used in Glivec, ruling that a new form of a known drug must show improved therapeutic effect, a decision that kept Indian generics of the leukaemia drug legal and...Open in Atlas Source
Nucleus: The compartment at the centre of a cell that holds the DNA, like a library that keeps the master copies of every instruction the cell might need.Open in Atlas Source
Number needed to screen (and number needed to diagnose): How many men have to be offered the test for one man to be saved from dying of prostate cancer, and how many extra cancers have to be found along the way. In the big European trial the answer at sixteen years was 570 men invited and 18 extra cancers diagnos...Open in Atlas Source
Numbness and nerve pain after breast surgery: Small sensory nerves are cut during breast and armpit surgery, so an area of the upper inner arm, armpit, chest wall or reconstructed breast is often numb, tingly or painful afterwards. Some feeling returns over months; for many people some of it does not,...Open in Atlas Source
Nutrition impact symptoms: The side-effects of cancer and its treatment that stop people eating: nausea, mouth soreness, taste changes, difficulty swallowing, early fullness, constipation, pain and low mood. Treating them is often the most effective nutrition intervention.Open in Atlas Source

O

Obesity-related cancers (IARC list of 13): Excess body fat is an established cause of thirteen cancers on the IARC list, including womb, oesophagus, kidney, liver, bowel, pancreas and postmenopausal breast cancer. It accounts for roughly 4 to 8% of cancers in high-income countries, second only to sm...Open in Atlas Source
Objective response rate (ORR): Objective response rate (ORR) is the percentage of patients whose tumours shrink by at least 30%.Open in Atlas Source
Obstruction and T4 disease in bowel cancer: Sometimes a bowel cancer is found only when it blocks the bowel or has grown through its outer wall into the peritoneum or a neighbouring organ. Both change the plan: a blockage may be relieved with a stent so that surgery can be done calmly a few weeks lat...Open in Atlas Source
Obstructive jaundice and biliary obstruction: Yellowing of the skin and eyes because a tumour blocks the bile duct, most often pancreatic or bile duct cancer. It causes itching, infection risk and dark urine, and it must be relieved (usually with a stent) before chemotherapy can be given safely.Open in Atlas Source
Ocular toxicity (keratopathy, blurred vision): Eye problems from cancer drugs: blurred vision and corneal damage from certain ADCs (belantamab, tisotumab), retinal fluid from MEK inhibitors, and inflammation from immunotherapy. Usually reversible with dose holds, but they need regular eye examinations.Open in Atlas Source
ODAC (Oncologic Drugs Advisory Committee): A panel of outside experts the FDA convenes to debate contentious cancer drug applications in public and vote on whether the evidence is adequate. The FDA usually, but not always, follows the vote.Open in Atlas Source
Oesophagectomy: Surgery that removes most of the food pipe (oesophagus) and rebuilds it by pulling the stomach up into the chest.Open in Atlas Source
Off-label: Prescribing an approved drug for a use not listed on its official label, for example a different cancer or an earlier stage. Legal and common in oncology, but insurers may refuse to pay and the evidence is often thinner.Open in Atlas Source
Oligometastatic disease: Cancer that has spread to only a few places, which may still be curable by treating each spot.Open in Atlas Source
Oligoprogression: When only one or two spots grow on an otherwise working targeted therapy; treat the spots and keep the pill.Open in Atlas Source
OMOP common data model and OHDSI: A shared format for patient records that lets hospitals around the world run the same study on their data without sharing it.Open in Atlas Source
On-target resistance mutations (gatekeeper, solvent-front, compound): When a cancer becomes resistant to a targeted pill, it often does so by changing the exact spot where the drug binds: a 'gatekeeper' or 'solvent-front' mutation. Next-generation drugs are designed to fit around these changes.Open in Atlas Source
Oncogene: A gene that, when over-activated by mutation or extra copies, pushes a cell to grow and divide. Think of an accelerator pedal stuck to the floor.Open in Atlas Source
Oncogene addiction: When a cancer depends so completely on one mutated gene that blocking it collapses the tumour.Open in Atlas Source
Oncology drug pricing and price transparency: New cancer drugs commonly launch above $150,000-$250,000 per year in the US, with prices set without reference to benefit and hidden behind rebates; other countries negotiate or assess cost-effectiveness. Pricing policy determines who gets treated.Open in Atlas Source
Oncology workforce: There are not enough oncologists, radiation therapists, pathologists, oncology nurses and pharmacists for the growing number of patients, in rich countries and especially in poor ones; burnout, geography and training pipelines shape who receives care.Open in Atlas Source
Oncoplastic breast surgery: Techniques borrowed from cosmetic surgery that let a surgeon take out a larger piece of breast and still leave a breast that looks like one, by moving the remaining tissue around or bringing in tissue from nearby.Open in Atlas Source
OncoTree cancer classification: OncoTree is a hierarchy of cancer types from tissue down to subtype, with short codes such as LUAD and BRCA, built for precision oncology and used by cBioPortal and AACR GENIE.Open in Atlas Source
Open licences: Apache-2.0, MIT and CC BY 4.0: MIT and Apache-2.0 are permissive software licences that let anyone use, change and redistribute code (Apache adds an explicit patent grant); CC BY 4.0 is the equivalent for data and text, requiring only attribution.Open in Atlas Source
Open weights, open code and gated models: Open weights means a model's trained parameters are published so anyone can run and adapt it; that is less than open source, which also needs the training code and data, and more than gated weights, which require a request and a licence click.Open in Atlas Source
Oral SERD: An oral SERD is a pill that destroys the oestrogen receptor rather than just blocking it, replacing the monthly fulvestrant injection.Open in Atlas Source
Orchiectomy: Surgical removal of a testicle: the diagnostic and first curative step for testicular cancer, or of both, as a cheap permanent form of hormone therapy in prostate cancer.Open in Atlas Source
Organ preservation (watch-and-wait, bladder-sparing, larynx preservation): Curing a cancer with drugs and radiotherapy so that the organ (rectum, bladder, larynx, limb) does not have to be removed, keeping surgery in reserve for the minority whose cancer regrows.Open in Atlas Source
Organoid: A tiny three-dimensional version of a tissue or tumour grown in the lab from a patient's own cells. Tumour organoids keep more of the original cancer's character than flat cell lines and can be used to test drugs on a patient's own cancer.Open in Atlas Source
Organs at risk and dose constraints: The healthy organs near a tumour that limit how much dose can be given, each with a maximum dose or dose-volume limit the plan must respect (for example, keeping the spinal cord below about 45 to 50 Gy).Open in Atlas Source
Orphan drug: A drug for a rare disease (in the US, fewer than 200,000 patients) that gets extra incentives, tax credits, fee waivers and seven years of market exclusivity, to make development worthwhile. Most cancers qualify, so most cancer drugs are orphans.Open in Atlas Source
Orphan Drug Act 1983: The 1983 US law that pays companies to develop drugs for rare diseases with seven years of market exclusivity, tax credits and fee waivers, which is why so many cancer drugs are first approved for a rare subtype.Open in Atlas Source
Orphan drug designation: A status for drugs treating rare diseases (under 200,000 US patients, or under 5 in 10,000 in the EU) that gives the company tax credits, fee waivers and seven to ten years of market exclusivity, to make rare-disease drug development worthwhile.Open in Atlas Source
Other-cause mortality: Dying of something that is not the cancer. In prostate cancer most men do, which makes it the outcome that decides how much any treatment can possibly help. It is also where the inequality that survives equal cancer care shows up, and almost no cancer servi...Open in Atlas Source
Out-of-distribution detection (Mahalanobis guard): Out-of-distribution detection flags an input that does not look like anything the model was trained on, so the model can refuse to predict instead of guessing; the Mahalanobis distance from the training cloud is the simplest such guard.Open in Atlas Source
Ovarian function suppression (OFS): Temporarily switching off the ovaries with injections (or removing them) so a premenopausal woman's cancer is starved of oestrogen.Open in Atlas Source
Overall survival (OS): Overall survival (OS) is how long patients live, full stop. It is the gold-standard endpoint.Open in Atlas Source
Overdiagnosis: Finding a cancer that would never have caused symptoms or death in a person's lifetime, so that the diagnosis and treatment bring harm without benefit. It is the main downside of screening.Open in Atlas Source
Overexpression: When a cell makes much more of a particular protein than normal cells do. Drugs that home in on that protein can then hit the tumour harder than healthy tissue.Open in Atlas Source
Overtreatment: Treating a cancer that was never going to cause trouble. It is the harm that overdiagnosis causes: the diagnosis itself does not leak urine or end erections, the operation does. Published estimates of how much prostate cancer is overdiagnosed range from und...Open in Atlas Source
Oxygen enhancement ratio: How many times more radiation a cell without oxygen needs to be killed compared with the same cell with oxygen: about 2.5 to 3 for X-rays, close to 1 for the heaviest particle beams.Open in Atlas Source

P

P-value: The probability of seeing a difference at least this large if the treatment actually did nothing. Below 0.05 (a 1 in 20 chance) is the conventional threshold for calling a result 'statistically significant'. It measures surprise, not the size of the benefit...Open in Atlas Source
Pack-year: The unit used to measure how much someone has smoked over a lifetime: one pack-year is twenty cigarettes a day for one year. Twenty a day for thirty years, or forty a day for fifteen, are both thirty pack-years.Open in Atlas Source
Paediatric drug laws: BPCA and PREA: Two US laws, one a carrot and one a stick, that get new drugs studied in children: BPCA gives six extra months of exclusivity for doing requested paediatric studies, and PREA requires paediatric assessments, though until 2020 cancer drugs mostly escaped it.Open in Atlas Source
Pain with gallbladder and bile duct cancer: Pain in the upper tummy is common with gallbladder cancer and can be controlled for most people with the right painkillers; tell the team early, keep a note of the pattern, and ask for the palliative care or pain team if it is not settling.Open in Atlas Source
Palliation in advanced triple-negative breast cancer: brain, bone, pleura, skin and end of life: Advanced triple-negative breast cancer spreads early to the brain, lungs, liver and bones. Brain metastases get focused radiotherapy or surgery, bone pain a single dose of radiotherapy and bone-protecting drugs, fluid around the lung drainage or a permanent...Open in Atlas Source
Palliation in colorectal cancer: obstruction, stents, stomas and liver capsule pain: What is done when a bowel cancer blocks the bowel, when the liver is studded with deposits and hurts, or when a tumour in the rectum bleeds and will not stop. A wire mesh tube, an operation to divert the bowel, radiotherapy, steroids and opioids each have a...Open in Atlas Source
Palliation in lung cancer: breathlessness, pleural effusion, blocked airway, bone and brain: What is done when a lung cancer makes breathing hard, fills the chest with fluid, blocks an airway, spreads to bone or reaches the brain. Most of it is quick, most of it works, and most of it is separate from treating the cancer itself.Open in Atlas Source
Palliation in pancreatic cancer: biliary and duodenal stents, coeliac plexus block, enzymes and cachexia: Most people with pancreatic cancer need treatment for a blocked bile duct, pain, poor digestion or weight loss alongside chemotherapy: a metal stent placed by endoscopy for jaundice, a duodenal stent or bypass for a blocked bowel, an alcohol block of the ne...Open in Atlas Source
Palliative: Treatment aimed at relieving symptoms and improving quality of life rather than curing the disease. Not the same as end-of-life care: palliative treatments are given alongside anticancer drugs at every stage.Open in Atlas Source
PAM50 / intrinsic subtypes: A 50-gene test that sorts breast cancers into luminal A, luminal B, HER2-enriched, and basal-like.Open in Atlas Source
Pancoast (superior sulcus) tumour: A lung cancer growing at the very top of the lung, where it presses on the nerves going to the arm and the nerves that control the eyelid and pupil. It usually announces itself as shoulder and arm pain rather than as a chest problem, so it is often treated...Open in Atlas Source
Pancreas protocol CT (pancreatic protocol CT, dual-phase thin-slice CT with structured reporting): A pancreas protocol CT is a scan tuned for the pancreas: thin slices taken at two timed moments after contrast dye so that the tumour, the arteries and the veins all show up sharply. It is the first test NICE asks for when pancreatic cancer is suspected, be...Open in Atlas Source
Pancreatic cancer drugs in England: NICE appraisals and the Cancer Drugs Fund (September 2026): In England the funded pancreatic cancer drugs are the older chemotherapies: FOLFIRINOX, gemcitabine with capecitabine, gemcitabine alone, and nab-paclitaxel with gemcitabine when other combinations are unsuitable. Liposomal irinotecan after gemcitabine was...Open in Atlas Source
Pancreatic cancer trials open today (registry snapshot and UK sites): Every phase 2 or 3 interventional trial that was recruiting, about to open or still running for pancreatic cancer on ClinicalTrials.gov in September 2026, with the hospitals in the United Kingdom that take part named where the registry lists them.Open in Atlas Source
Pancreatic cancer: the failed and stopped programmes and why: Pancreatic cancer has a long list of phase 3 trials that added a new drug to standard chemotherapy and found nothing: a stroma-degrading enzyme, an interleukin-10, a stemness inhibitor, a BTK inhibitor, a metabolic inhibitor, an anti-fibrotic antibody, two...Open in Atlas Source
Pancreatic enzyme replacement therapy (PERT, pancreatin, Creon) for pancreatic exocrine insufficiency: why and how to take it: Most pancreatic cancers stop the gland's digestive enzymes reaching the gut, so fat passes through undigested and weight falls. Enzyme capsules taken with every meal and snack replace what is missing. NICE says everyone whose cancer cannot be removed should...Open in Atlas Source
Pancreatic intraepithelial neoplasia (PanIN), the microscopic precursor of pancreatic cancer: PanIN is the name for abnormal cells lining the small pancreatic ducts that can, over years, turn into pancreatic cancer. It is too small to see on any scan and is found only under the microscope, so it cannot be screened for directly. Pathologists now grad...Open in Atlas Source
Partial response: The tumours have shrunk substantially (by at least 30% in total diameter) but not disappeared. Together with complete responses it makes up a trial's response rate.Open in Atlas Source
Partial-breast irradiation: Treating only the part of the breast around where the lump was, instead of the whole breast, on the grounds that almost all recurrences happen there. It works, but which schedule is used decides whether the breast looks better or worse afterwards.Open in Atlas Source
Pathologic complete response (pCR): No invasive cancer left in the breast and lymph nodes when the surgeon removes the tissue after pre-surgery treatment.Open in Atlas Source
Pathology foundation models: UNI, UNI2, Virchow2, CTransPath, CONCH, TITAN: Pathology foundation models are image encoders pretrained without labels on millions of slide tiles; UNI and CONCH come from the Mahmood Lab at Harvard, Virchow from Paige, and CTransPath was an early transformer version.Open in Atlas Source
Pathway activation state (phosphosignalling): Whether a signalling pathway is switched on is set by phosphorylation of its proteins, not by how much of them is present, so it has to be measured at the protein level.Open in Atlas Source
Payload (ADC): The payload is the poison an ADC carries, usually a chemotherapy far too toxic to give on its own.Open in Atlas Source
PBD dimer (SG3199 / tesirine): The PBD dimer SG3199 crosslinks DNA in the minor groove without distorting it, so cells fail to detect the damage; it kills at picomolar concentrations, so ADCs need only a low drug-to-antibody ratio. Fluid retention, skin reactions and light sensitivity st...Open in Atlas Source
PD-L1 assay discordance (SP142, SP263 and 22C3 in breast cancer): Three commercial PD-L1 stains give different answers on the same breast tumour: the SP142 assay used with atezolizumab called fewer than half of tumours positive while the 22C3 and SP263 assays called about three quarters. Because the pembrolizumab licence...Open in Atlas Source
PD-L1 combined positive score 10 in triple-negative breast cancer: In metastatic triple-negative breast cancer the immunotherapy pembrolizumab is only given when a PD-L1 stain of the tumour scores 10 or more on the combined positive score, because that is the group in which the trial showed people lived longer. For early d...Open in Atlas Source
PD-L1 expression testing (22C3, SP142, SP263): A stain on the tumour biopsy that measures how much of the PD-L1 'don't attack me' protein is present, scored as a tumour proportion or combined positive score. Higher levels usually mean checkpoint inhibitors work better, and approvals in lung, triple-nega...Open in Atlas Source
Pelvic floor muscle exercises: Exercises that strengthen the sling of muscle under the bladder and bowel, used to reduce leaking and to help erections.Open in Atlas Source
Percentage of Gleason pattern 4: How much of the cancer in a biopsy is the more aggressive pattern 4 rather than the slower pattern 3. Two men can both be told grade group 2, one with 5 per cent pattern 4 and one with 45 per cent, and the number is what separates them.Open in Atlas Source
Performance status (ECOG, Karnofsky): A simple score of how well a patient can get about and look after themselves: ECOG 0 is fully active, 1 restricted from strenuous work, 2 up more than half the day, 3 in bed more than half the day, 4 bedbound. It predicts how treatment will be tolerated and...Open in Atlas Source
Perineural invasion (PNI): Cancer cells growing along the sheath of a nerve. Nerves act as tracks for spread, so this finding predicts recurrence, especially in pancreatic, prostate and head and neck cancers.Open in Atlas Source
Peripheral neuropathy (chemotherapy-induced): Nerve damage from chemotherapy that causes numbness, tingling and pain in the hands and feet, and sometimes weakness or hearing loss. It builds up with each dose, can be permanent, and is the main reason oxaliplatin, taxanes and vincristine have to be stopp...Open in Atlas Source
Peritoneal cancer index: The peritoneal cancer index is the score a surgeon gives the abdomen at operation, region by region, for how much tumour is on its lining. It decides whether stripping the disease out is worth attempting, and it is the number quoted when a specialist centre...Open in Atlas Source
Peritoneal metastases from bowel cancer: Bowel cancer can seed the lining of the abdomen rather than travel to the liver or lungs. Where the deposits are confined to that lining and can all be removed, specialist centres offer an operation to strip them out. Adding heated chemotherapy into the abd...Open in Atlas Source
Peritoneal metastasis: Spread across the lining of the abdomen, the most common way stomach cancer recurs and the hardest to treat.Open in Atlas Source
Peritoneum and peritoneal metastases: The thin membrane lining the abdominal cavity and covering the bowel. Cancers of the ovary, stomach, colon, appendix and pancreas seed it with small, poorly vascularised deposits that CT under-detects and drugs reach badly, which is why surgery with heated...Open in Atlas Source
Permutation test and the Mann-Whitney U test: A permutation test builds the null distribution by shuffling labels (or spot positions) many times and asks how often chance does as well as the real result; the Mann-Whitney U test compares two groups by ranks without assuming a normal distribution.Open in Atlas Source
Persistent chemotherapy-induced alopecia: Hair that has not returned to its old density six months or more after chemotherapy ended. It is the effect patients are least often warned about beforehand, it is commonest after taxanes and after transplant conditioning, and it is usually thinning rather...Open in Atlas Source
Persistent radiation-induced alopecia: Radiotherapy takes hair only where the beam passes through the scalp, and whether it returns depends on the dose the follicles received. Below a threshold it regrows in months; above it, the patch can stay thin for good.Open in Atlas Source
Ph-like (BCR::ABL1-like) acute lymphoblastic leukaemia: Ph-like leukaemia has the gene-expression fingerprint of Philadelphia-positive leukaemia without the Philadelphia chromosome; behind it are dozens of kinase fusions and JAK pathway lesions, and finding which one is present tells doctors whether an imatinib-...Open in Atlas Source
Ph-positive ALL: Ph-positive ALL is acute lymphoblastic leukaemia carrying the Philadelphia chromosome. It was once the worst kind and is now often the best-controlled, thanks to TKIs and blinatumomab.Open in Atlas Source
Pharmacogenomics: Pharmacogenomics studies how a person's genes, and a tumour's genes, change the way drugs work or cause harm.Open in Atlas Source
Pharmacokinetics (PK), half-life and exposure: How a drug moves through the body: how much is absorbed, how high the blood level gets, how long it lasts (half-life) and how it is cleared. These numbers decide the dose, the schedule and whether a pill can be taken with food or other medicines.Open in Atlas Source
Phase 1, 2 and 3 trials: The three stages a new drug passes through: phase 1 finds a safe dose in a few dozen patients, phase 2 looks for signs of activity in a hundred or so, and phase 3 compares it with the standard treatment in hundreds or thousands.Open in Atlas Source
Philadelphia chromosome (Ph+, BCR::ABL1): A swapped piece between chromosomes 9 and 22 that fuses two genes into BCR::ABL1, a runaway kinase. It causes chronic myeloid leukaemia and a hard-to-treat quarter of adult acute lymphoblastic leukaemia, and was the target of imatinib, the first modern targ...Open in Atlas Source
Phlebotomy (venesection): Removing about a pint of blood through a vein, as in a blood donation, to bring the red cell count down. It is the oldest treatment in polycythaemia vera and still the first.Open in Atlas Source
Phosphorylation: Attaching a small phosphate tag to a protein, which changes its shape and switches it on or off. It is the cell's main way of passing signals from one protein to the next.Open in Atlas Source
PI-RADS (Prostate Imaging Reporting and Data System): The international scoring system radiologists use to say how likely a prostate MRI finding is to be a serious cancer, from 1 (very unlikely) to 5 (very likely). British NHS reports usually do not use it: NICE asks for a 5-point Likert score instead, and the...Open in Atlas Source
PIPL (China Personal Information Protection Law 2021): China's 2021 privacy law, in force since November 2021, treats medical and health data as sensitive information requiring separate consent, and together with the Data Security Law restricts sending patient data out of China, which shapes every international...Open in Atlas Source
Pivotal (registrational) trial: The trial (usually a randomised phase 3, sometimes a large phase 2) whose results are submitted to regulators as the main evidence for approval. When a company calls a trial 'registrational' it is signalling that this is the one that decides.Open in Atlas Source
Placebo: An inactive look-alike treatment given to the comparison group in a trial so that neither patients nor doctors can tell who is on the real drug. In cancer trials it is added on top of standard treatment, never given instead of it.Open in Atlas Source
Plasma EBV DNA: Fragments of Epstein-Barr virus DNA in the blood that measure nasopharyngeal carcinoma: used to screen healthy people in endemic regions, to stage, to decide who needs extra treatment after radiotherapy, and to detect relapse.Open in Atlas Source
Platinum drugs and PARP inhibitors: the newer leukaemia risk: The leukaemia risk after chemotherapy was described in the era of mustards and etoposide, and it did not stay there. Platinum drugs carry it, PARP inhibitors raise it about two and a half times against placebo, and lenalidomide with oral melphalan raises it...Open in Atlas Source
Platinum-sensitive / platinum-resistant: Whether a cancer that responded to platinum chemotherapy came back more than six months later (sensitive, so platinum can be used again) or sooner (resistant, so something else is needed). The dividing line shapes ovarian and small-cell lung cancer treatment.Open in Atlas Source
Pleura: The two-layered lining around each lung. Mesothelioma grows from it, lung and breast cancers spread to it, and fluid collecting between its layers causes breathlessness.Open in Atlas Source
Pleurodesis and indwelling pleural catheter: Ways to stop fluid repeatedly collecting around the lung: either glue the two pleural layers together with talc, or leave a small tunnelled drain the patient empties at home.Open in Atlas Source
Pneumonectomy: Removing an entire lung. Now rare in cancer surgery because the cost in breathing capacity is high.Open in Atlas Source
Pneumonitis: Inflammation of the lung tissue itself, caused by a treatment rather than an infection. It shows up as a new cough, breathlessness on exertion or a fall in oxygen levels, and it is the reason a new breathlessness on immunotherapy, an antibody-drug conjugate...Open in Atlas Source
POD24: progression of follicular lymphoma within two years, and why it changes the plan: Most follicular lymphoma comes back slowly and is treated again without much loss of life expectancy. For about one in five people it comes back within two years of the first chemotherapy, and that group needs a different plan, usually a biopsy first and th...Open in Atlas Source
POLE ultramutation (POLEmut): A pathogenic mutation in the proofreading part of the POLE gene gives an endometrial tumour hundreds of mutations per megabase and, paradoxically, one of the best outlooks of any womb cancer, so finding it can spare a woman chemotherapy or radiotherapy.Open in Atlas Source
Polygenic risk score (PRS): A single number adding up hundreds of common, individually tiny genetic differences to say whether a man's inherited risk of prostate cancer is above or below average. It is not a test for a faulty gene like BRCA2, and it says nothing about how aggressive a...Open in Atlas Source
Polyp types in the bowel: A polyp is a growth on the lining of the bowel. Most are harmless, but two families can turn into cancer: adenomas, the classic route, and serrated lesions, the flatter and easier-to-miss route. Which kind you had, how many, how big and whether the cells lo...Open in Atlas Source
Porcelain gallbladder: A gallbladder whose wall has turned hard and chalky with calcium after years of inflammation, seen on a scan or X-ray. It was long thought to lead to cancer in many cases; newer studies find the risk is real but much smaller, so whether to remove a symptom-...Open in Atlas Source
Port-site metastasis: Cancer growing in the small keyhole wounds of a laparoscopic operation, seeded when a gallbladder containing an unsuspected cancer was pulled out through them. It was once seen in up to one in five incidental gallbladder cancers; it is now about one in ten,...Open in Atlas Source
Portal vein tumour thrombus (macrovascular invasion): Liver cancer growing into the main vein that brings blood from the gut to the liver. It marks advanced disease, rules out most surgery and transplant, and makes some local treatments unsafe.Open in Atlas Source
Positive predictive value (PPV): Positive predictive value (PPV) is the chance that a positive test result is actually right: true positives divided by all positives. Because it falls as a disease becomes rarer, even a specific screening test gives mostly false alarms when prevalence is lo...Open in Atlas Source
Post-PV myelofibrosis (spent phase): The late stage some people with polycythaemia vera reach after many years, when the marrow scars over, the red count falls and the spleen swells. It is treated as myelofibrosis.Open in Atlas Source
Post-transcriptional and post-translational regulation: Cells control genes after the messenger RNA is made, by editing, transporting and degrading it and by modifying the finished protein, which is why RNA levels and protein activity can disagree.Open in Atlas Source
Pragmatic trial: A pragmatic trial tests a treatment the way it would actually be used: ordinary patients, ordinary clinics, usual care as the comparison and an outcome that matters to patients, so the answer applies in the real world and not only in the trial.Open in Atlas Source
Pre-registered experiment: Pre-registration means writing down the hypothesis, the analysis and the success criterion before running the experiment, so the result cannot be quietly redefined afterwards.Open in Atlas Source
Pre-specified vs post-hoc analysis: Whether an analysis was planned and written down before the data were seen (pre-specified) or invented afterwards (post-hoc). Post-hoc findings, especially in subgroups, are prone to be chance and count as hypotheses for a new trial, not as evidence.Open in Atlas Source
Preclinical: Everything done to a potential drug before it is given to a human: lab experiments, animal testing, and the safety and manufacturing work regulators require. Most candidates never make it out.Open in Atlas Source
Prehabilitation (the pre-treatment window): Using the weeks between diagnosis and surgery or chemotherapy to get fitter, better nourished and psychologically prepared, so treatment goes better and recovery is faster.Open in Atlas Source
PRETEXT and CHIC risk groups (hepatoblastoma): PRETEXT describes how many of the liver's four sections a child's hepatoblastoma occupies before any treatment, with letters for spread into veins, outside the liver, rupture or metastases; combined with age and the AFP level in the CHIC system it decides w...Open in Atlas Source
Priapism: An erection that will not go down: after four hours it is an emergency, because the tissue starts to be damaged.Open in Atlas Source
Primary tumour: The original tumour where a cancer started. Cancer is named after this site for life: a breast cancer that spreads to the liver is still breast cancer, not liver cancer.Open in Atlas Source
Primary, secondary and co-primary endpoints: The primary endpoint is the single measurement a trial is designed and sized to test, declared in advance; if it is met, the trial is 'positive'. Secondary endpoints are additional measures that can support but not rescue a trial that missed its primary.Open in Atlas Source
Principal component analysis (PCA) as a feature compressor: PCA rotates the data onto the directions of greatest variance and keeps the top few, compressing twenty thousand genes into a few hundred numbers before a model sees them.Open in Atlas Source
Prodrug: A drug given in an inactive form that the body converts into the active medicine. It can make a drug easier to take, longer-lasting, or active only where it is needed.Open in Atlas Source
Prognosis: The expected course of a disease: how likely it is to be cured, how long a person is likely to live, and how they are likely to feel. Always an estimate based on groups of similar patients, never a prediction for one person.Open in Atlas Source
Prognostic Index for T-cell lymphoma (PIT): A four-item score that estimates the outlook in nodal T-cell lymphoma, built because the index used for B-cell lymphoma separated these patients poorly. It counts age over 60, a performance status of 2 or worse, a raised lactate dehydrogenase, and lymphoma...Open in Atlas Source
Progression: The cancer is growing or spreading despite treatment, or after it. Progression usually means the current drug has stopped working and it is time to switch to the next line.Open in Atlas Source
Progression-free survival (PFS): Progression-free survival (PFS) is how long patients live without their cancer growing.Open in Atlas Source
Progressive disease and radiographic progression: The point at which a cancer is judged to be growing again despite treatment, usually a 20% increase on scans or a new lesion (RECIST). It ends progression-free survival, usually triggers a change of treatment, and defines 'lines' of therapy.Open in Atlas Source
Project FrontRunner: An FDA initiative encouraging companies to test new cancer drugs earlier in the disease, in first-line or curative settings, rather than only after everything else has failed.Open in Atlas Source
Project Optimus: An FDA programme pushing companies to find the best dose of a cancer drug, not just the highest tolerable one.Open in Atlas Source
Project Orbis: Project Orbis is a scheme where the FDA and partner regulators (Australia, Canada, UK, Switzerland, Singapore, Brazil, Israel) review a cancer drug at the same time.Open in Atlas Source
Proliferation: Rapid multiplication of cells. A tumour's proliferation rate, often measured by the marker Ki-67, tells you how fast it is growing and how it may respond to treatment.Open in Atlas Source
Prophylactic (preventive) cholecystectomy: Removing a gallbladder that contains stones before it causes trouble, in the hope of preventing a cancer that almost always arises in a gallbladder with stones. Chile has run a national programme since 2006.Open in Atlas Source
Prophylactic cranial irradiation (PCI): Giving the brain a preventive dose of radiation (25 Gy in 10 sessions) before any metastasis can be seen, mainly in small-cell lung cancer, which spreads to the brain in over half of patients. Its value is disputed now that MRI surveillance is routine, and...Open in Atlas Source
Prostate cancer drugs in England: what NICE recommends, and what it refuses: Having a licence is not the same as being funded. In England several prostate cancer drugs that are approved elsewhere are not recommended by NICE, and one man in the same position in Manchester and in Boston will be offered different treatment.Open in Atlas Source
Prostate cancer programmes that failed, and what each failure taught: More large prostate cancer trials have failed than succeeded. The failures cluster: immunotherapy in unselected men, drugs aimed at blood vessels, drugs aimed at bone signalling, and drugs that improved scans without extending life.Open in Atlas Source
Proteasome inhibitor (bortezomib, carfilzomib, ixazomib): Drugs that block the cell's protein-recycling machine. Myeloma cells make huge amounts of antibody protein and choke on the backlog when the proteasome is blocked; normal cells cope far better.Open in Atlas Source
Protein: The molecular machines that do almost everything in a cell: receive signals, copy DNA, build structures, digest food. Most cancer drugs work by binding to one specific protein.Open in Atlas Source
Proton range uncertainty and the range margin: A proton beam stops at a depth that cannot be predicted exactly, so planners deliberately aim it a few millimetres past the tumour. At one leading centre the allowance is 3.5 per cent of the beam's range plus 1 millimetre, which for a beam reaching 20 centi...Open in Atlas Source
Provenance fields for research data: Provenance fields record where each data file came from and how it was processed (source, accession, pipeline version, genome build, date, checksum), so a result can be traced and reproduced.Open in Atlas Source
PRRT (peptide receptor radionuclide therapy): A radioactive drug for neuroendocrine tumours: a small peptide that homes to the somatostatin receptor on the tumour cells carries lutetium-177, which irradiates them from within. Given four times, two months apart.Open in Atlas Source
PSA (prostate-specific antigen): A blood protein made by the prostate; raised levels prompt further tests, and falling levels show treatment is working.Open in Atlas Source
PSA density: The PSA divided by the volume of the prostate measured on the scan. A big prostate makes more PSA without any cancer in it, so dividing by size separates a raised PSA that needs a biopsy from one that does not.Open in Atlas Source
PSA doubling time: How long the PSA takes to double, used to tell a slow rise from a fast one.Open in Atlas Source
PSA kinetics: PSA doubling time and PSA density: How fast PSA is rising matters more than its level: a doubling time under ten months after surgery or radiotherapy, or under nine months in castration-resistant disease, marks the men whose cancer is moving quickly and who benefit from earlier hormone thera...Open in Atlas Source
PSA50 / PSA90 response: PSA50 is the share of patients whose PSA falls by at least half on treatment, and PSA90 the share whose PSA falls by 90%.Open in Atlas Source
PTEN loss: PTEN is the brake on the PI3K/AKT growth pathway; when a tumour deletes or mutates it (seen as a lost stain or on sequencing) the pathway runs unopposed. In hormone-treated breast cancer PTEN loss is one of the three changes that qualify a woman for capivas...Open in Atlas Source
Pulmonary nodule: A small round shadow in the lung on a CT scan, usually under 3 cm. Most are scars or old infections, not cancer. What decides the next step is size, density and whether it grows between scans, which is why so many are simply rescanned rather than biopsied.Open in Atlas Source

Q

QT prolongation: A change on the heart's electrical trace, caused by some drugs blocking a potassium channel (hERG), that in rare cases sets off a dangerous rhythm. Drugs that do this need ECG checks and care with other medicines and low potassium or magnesium.Open in Atlas Source
Quality of life: How a patient actually feels and functions day to day: symptoms, energy, mood, ability to work and live normally. Measured with questionnaires, it is the outcome that matters most alongside survival, and the one trials have historically neglected.Open in Atlas Source
Quality of life and patient-reported outcomes (QoL, PRO): Measures of how patients themselves feel and function during treatment (pain, fatigue, nausea, daily activities), collected by questionnaire rather than by the doctor. Regulators and payers now expect them alongside survival, and clinician grading is known...Open in Atlas Source
Quality-adjusted survival (QALYs and Q-TWiST): Quality-adjusted survival counts time alive but discounts the months spent with severe side effects or progressing disease, so a treatment that adds three months of misery scores lower than one that adds three good months.Open in Atlas Source
Quantile normalisation, rank transforms and z-scores: Quantile normalisation forces every sample's expression values onto the same distribution by rank, and a z-score expresses each gene as standard deviations from its mean; both are ways to make data from different platforms comparable.Open in Atlas Source

R

R-CHOP (lymphoma chemoimmunotherapy): R-CHOP is the standard first treatment for diffuse large B-cell lymphoma: rituximab (an antibody against CD20) plus four chemotherapy drugs (cyclophosphamide, doxorubicin, vincristine, prednisone), given every three weeks for six cycles with curative intent...Open in Atlas Source
R-ISS / R2-ISS staging: R-ISS is the myeloma staging system, combining blood markers with high-risk chromosome changes to predict outcome.Open in Atlas Source
R-spondin fusion: R-spondin fusions are rearrangements that make a bowel tumour overproduce a protein which turns the Wnt growth pathway up from outside the cell. They occur in about one colon tumour in ten and almost never alongside the usual APC fault, so they look like an...Open in Atlas Source
R0 and R1 margins in pancreatic cancer: the 1 mm rule and standardised specimen reporting: After a pancreatic cancer is removed, the pathologist checks whether cancer reaches the cut edges of the specimen. In the UK, cancer within one millimetre of an edge counts as an incomplete (R1) resection even if it does not touch it. Reported this way most...Open in Atlas Source
RACE for Children Act: A US law that makes drug companies test new targeted cancer drugs in children whenever the drug's target matters in a childhood cancer, instead of letting them skip children because their cancers are rare.Open in Atlas Source
Radiation dermatitis (skin reaction): Redness, dryness, itching and sometimes peeling of the skin in the treated area, building up over the course and settling a few weeks after it ends. Severe in a minority, worst in skin folds and after chemotherapy.Open in Atlas Source
Radiation necrosis (brain): Death of brain tissue months to years after radiosurgery or high-dose brain radiotherapy, which can look exactly like tumour growing back on a scan.Open in Atlas Source
Radiation pneumonitis and lung fibrosis: Inflammation of the lung one to six months after chest radiotherapy, causing cough, breathlessness and fever; usually settles with steroids but can leave permanent scarring.Open in Atlas Source
Radical (extended) cholecystectomy: The cancer operation for gallbladder cancer: the gallbladder (if still present) is removed together with a rim of the liver it sits against and the lymph nodes along the bile duct and liver blood vessels. After an incidental cancer it is done as a second op...Open in Atlas Source
Radical cystectomy: Removing the bladder (and nearby organs) for bladder cancer that has grown into the muscle wall; urine is then diverted through a stoma or a new bladder made of bowel.Open in Atlas Source
Radical prostatectomy: Removing the entire prostate gland and seminal vesicles for localised prostate cancer, now almost always with a robot.Open in Atlas Source
Radiofrequency ablation (RFA): Killing a tumour by heating it with an electrical current through a needle placed under image guidance, without removing it.Open in Atlas Source
Radiographic progression-free survival (rPFS): In cancer that has already spread, this is the time until the scans show it getting worse, or the man dies. It deliberately ignores a rising PSA on its own, because in prostate cancer the PSA can rise for reasons that do not mean the treatment has stopped w...Open in Atlas Source
Radioiodine therapy (I-131): Swallowing a capsule of radioactive iodine after thyroid surgery: thyroid cells (including cancer cells) are the only ones that soak up iodine, so the radiation destroys leftover thyroid tissue and metastases while sparing everything else. It was the first...Open in Atlas Source
Radioiodine-refractory (RAI-R) thyroid cancer: Thyroid cancer that no longer takes up radioactive iodine, or keeps growing despite it. This is when kinase inhibitor pills come in.Open in Atlas Source
Radiology imaging as a data modality (CT, MRI, TCIA): CT, MRI and PET scans are a data modality in their own right; public archives such as TCIA hold de-identified scans, some linked to TCGA tumours, for training imaging models.Open in Atlas Source
Radiotherapy: Using high-energy X-rays or particles to damage the DNA of cancer cells in a precisely aimed volume of the body. On its own it cures early prostate, larynx, cervix and skin cancers, it is combined with chemotherapy in head and neck, lung, oesophageal and re...Open in Atlas Source
Radiotherapy after mastectomy: Radiotherapy to the chest wall, and often the nearby lymph node areas, after the breast has been removed. It clearly helps women with cancer in several lymph nodes. For women with one to three involved nodes treated with modern drugs, a trial that reported...Open in Atlas Source
Radiotherapy and second cancers: field, dose and age at exposure: A radiation-induced cancer appears in or at the edge of the treated area, usually more than ten years later, and the risk rises with the dose the organ received and falls with the age at which the person was treated. Which organs sat in the field is therefo...Open in Atlas Source
Radiotherapy for skin cancer: Radiotherapy cures most skin cancers without an operation, and is chosen when surgery would take too much, when someone is too frail for it, or when they refuse it. The one trial that compared it head to head with surgery found surgery better on both cure a...Open in Atlas Source
Radiotherapy in lymphoma: involved-site fields, 24 Gy, 4 Gy and total skin electron therapy: Lymphoma is one of the most radiation-sensitive cancers there is, so the doses are low and the fields are small. Two doses of 2 Gy can shrink a painful node in a fortnight; 24 Gy can cure a stage I follicular lymphoma.Open in Atlas Source
Radon: A radioactive gas that seeps out of the ground into buildings, with no smell and no taste. It is the largest natural source of radiation most people meet and the second commonest cause of lung cancer after smoking. A home can be tested with a posted detecto...Open in Atlas Source
Randomised trial: A trial in which a coin toss (done by computer) decides which treatment each patient gets, so the groups are alike in every way except the treatment. It is the only reliable way to prove a treatment causes a benefit.Open in Atlas Source
Rare cancers: Rare cancers are those with fewer than about 6 new cases per 100,000 people per year. Individually rare, together they are a quarter of all cancers and have worse survival because of late diagnosis, few trials and scattered expertise.Open in Atlas Source
Rash and skin toxicity (acneiform rash, paronychia): Skin reactions from cancer drugs, ranging from the acne-like rash that nearly everyone on an EGFR inhibitor gets (a sign the drug is working) to painful nail-fold infections, itching, and rare severe blistering reactions.Open in Atlas Source
Re-irradiation: Giving radiotherapy again to a region that has already been treated, once thought impossible because normal tissues remember the first dose. Modern precision techniques make it feasible in selected patients.Open in Atlas Source
Reading a hazard ratio: A hazard ratio of 0.70 means that at any given moment patients on the new treatment had 30% less risk of the event (death, progression) than those on the comparison. It says nothing about how many months that is worth.Open in Atlas Source
Real-Time Oncology Review (RTOR) and Assessment Aid: FDA processes that let reviewers start on trial data before the full application is filed, speeding approvals by months.Open in Atlas Source
Real-world evidence: Data from routine care rather than clinical trials, used to check whether results hold outside the trial population.Open in Atlas Source
Receptor: A protein, usually on the cell surface, that catches a specific signal molecule from outside and relays the message inside, like a doorbell wired to the cell's controls.Open in Atlas Source
Receptor conversion: when the receptors change between the primary and a recurrence: The receptors measured on the original tumour are not always the receptors of a cancer that comes back years later. On meta-analysis about a fifth of oestrogen receptor-positive primaries had become negative in their metastases, and about half had lost the...Open in Atlas Source
Rechallenge and retreatment: Giving a drug again after a break, on the theory that the cancer's resistance faded while it was off the drug. Sometimes it works: bowel cancers can respond again to EGFR antibodies once resistant clones have receded.Open in Atlas Source
RECIST: RECIST is the rulebook for measuring whether tumours have grown or shrunk on scans.Open in Atlas Source
Recommended phase 2 dose (RP2D): The dose and schedule chosen at the end of a phase 1 trial to test in larger trials, based on safety, blood levels and early signs of activity. It is often, but no longer always, the maximum tolerated dose.Open in Atlas Source
Recurrence and relapse: The cancer has come back after a period in which it could not be detected. 'Recurrence' is the usual word for solid tumours and 'relapse' for blood cancers; they mean the same thing.Open in Atlas Source
Reed-Sternberg cell: The Reed-Sternberg cell is the giant, often two-nucleus cancer cell of Hodgkin lymphoma; it makes up only about 1% of the tumour, and the rest is immune cells it has recruited.Open in Atlas Source
Refractory: Cancer that does not respond to a treatment at all, or grows straight through it. Distinct from relapse, where the cancer responded first and came back later.Open in Atlas Source
Regimen and cycles: A regimen is a named recipe of drugs, doses and timing; a cycle is one round of it, usually two to four weeks, giving normal tissues time to recover before the next. 'Six cycles of FOLFOX' means six repeats of that recipe.Open in Atlas Source
Registry-based randomised trial: A registry-based trial randomises patients who are already being tracked by a national or disease registry and uses the registry, not trial visits, to record what happens to them, making very large trials cheap enough to run.Open in Atlas Source
Regrowth after chemotherapy (chemo curls): Hair usually starts to come back two to three months after the last dose of chemotherapy, and it often comes back a different texture or colour: straight hair curly, dark hair grey or white. Most of that settles over the following year or two.Open in Atlas Source
Regulation (EC) No 141/2000: EU orphan medicines: The EU's 2000 answer to the US Orphan Drug Act: ten years during which no similar medicine may be authorised for the same rare disease, plus fee reductions and scientific advice, for conditions affecting no more than 5 in 10,000 people.Open in Atlas Source
Regulation (EC) No 1901/2006: EU paediatric medicines: Since 2007 every new medicine in the EU must come with an agreed plan for studying it in children, or a waiver, and completing the plan earns six extra months of patent protection; a loophole let adult-cancer drugs skip children, which is now being closed.Open in Atlas Source
Regulation (EC) No 726/2004: the EU centralised procedure: The 2004 EU regulation under which every new cancer medicine is assessed once by the European Medicines Agency and authorised for all member states by the European Commission, and which also carries the rules for conditional authorisation and compassionate...Open in Atlas Source
Regulators beyond the FDA (EMA/CHMP, MHRA, PMDA, NMPA, TGA): Every country or bloc has its own drug regulator: the EMA (with its CHMP committee) for the EU, the MHRA for the UK, the PMDA for Japan, the NMPA for China, the TGA for Australia. The same drug can be approved in one place years before another, or on differ...Open in Atlas Source
Relapsed / refractory (R/R): Relapsed means the cancer came back after responding; refractory means it never responded or grew during treatment. 'R/R' is the label on most trials of new blood cancer drugs.Open in Atlas Source
Relative biological effectiveness (RBE): How many grays of ordinary X-rays you would need to match the damage from one gray of this radiation. Protons are treated as 1.1 times as damaging as X-rays; that number is a convention, and the true value is higher where the beam stops.Open in Atlas Source
Remission: When the signs of cancer have shrunk (partial remission) or disappeared entirely (complete remission). It is not the same as cure, because cells too few to detect may remain.Open in Atlas Source
Reproducibility and negative results: A result is reproducible when someone else can get it again from the same data and code; a negative result is an experiment that did not show the hoped-for effect, and reporting it is how a field stops repeating dead ends.Open in Atlas Source
Research use only (RUO): A research use only label means a test, reagent or model has not been validated or cleared for making decisions about a patient and must not be used that way.Open in Atlas Source
Resectability classes for pancreatic cancer (NCCN anatomical criteria and the 2017 international consensus): Surgeons class a pancreatic cancer as resectable, borderline resectable or locally advanced by how far it wraps around the arteries and veins behind the pancreas on the CT scan, measured in degrees of contact. Less than half way round an artery, or a vein t...Open in Atlas Source
Resectability in lung cancer: Two separate questions are hidden in the word operable. Can the tumour be removed completely with a margin, which is anatomy? And can this person survive the operation and live without the lung tissue it takes, which is physiology? A no to either makes the...Open in Atlas Source
Resectable, borderline resectable and unresectable: The surgeon's verdict on whether the tumour can be completely removed. Resectable means yes; unresectable means it has wrapped around vital vessels, is too extensive or the patient is too frail; borderline means maybe, especially after chemotherapy shrinks it.Open in Atlas Source
Resection margins (R0 / R1 / R2): Whether the edge of the removed tissue is free of cancer. R0 means clear under the microscope, R1 means microscopic cancer at the edge, R2 means visible tumour left behind. R0 is what 'complete resection' means.Open in Atlas Source
Residual cancer burden (RCB): A pathology score for how much cancer remains in the breast and lymph nodes after pre-surgery treatment, from 0 (none) to III (a large amount), combining tumour bed size, cellularity and nodal involvement. RCB-II or III after neoadjuvant therapy predicts a...Open in Atlas Source
Residual disease after neoadjuvant therapy in triple-negative breast cancer: the decision point: When triple-negative breast cancer is still present at surgery after pre-operative chemotherapy and pembrolizumab, the amount left (the residual cancer burden) is what decides the next treatment: a year of olaparib for inherited BRCA carriers, capecitabine...Open in Atlas Source
Response-adaptive randomisation: In a response-adaptive trial the computer tilts the odds as results come in, so later patients are more likely to be assigned to the arm that seems to be working and arms that are failing are dropped.Open in Atlas Source
Retroperitoneum: The space at the back of the abdomen, behind the gut's lining, holding the kidneys, adrenals, pancreas, aorta and the para-aortic lymph nodes. Tumours here grow large before they are felt.Open in Atlas Source
Reverse-phase protein array (RPPA): RPPA spots tiny amounts of protein extract from many tumours onto a slide and probes them with antibodies, measuring a few hundred proteins and phosphoproteins in each sample at once.Open in Atlas Source
Richter transformation: When slow CLL suddenly turns into an aggressive lymphoma. Rare, hard to treat, and the focus of new immunotherapy trials.Open in Atlas Source
Ridge regression and the multilayer perceptron: Ridge regression is linear regression with a penalty that shrinks coefficients, which keeps it stable when there are more genes than samples; a multilayer perceptron is the simplest neural network, a few fully connected layers.Open in Atlas Source
Right to Try Act 2018 and state right-to-try laws: A 2018 US law letting patients with life-threatening illnesses ask a company directly for a drug that has passed phase 1 without going through the FDA; companies still decide, and in practice most access happens through the older expanded access route.Open in Atlas Source
Risk factor: Anything that raises the chance of developing a cancer: smoking, alcohol, obesity, sunlight, certain infections, inherited genes, age. Around 40% of cancers in high-income countries are attributable to modifiable factors, so having a risk factor does not me...Open in Atlas Source
Risk score and risk percentile: A risk score is a model's estimate of how likely a bad outcome is; a risk percentile says where that estimate sits compared with a reference group of patients.Open in Atlas Source
Risk-reducing surgery for BRCA carriers (bilateral and contralateral mastectomy, salpingo-oophorectomy): Women who carry a BRCA1 or BRCA2 fault can choose to have both breasts removed before any cancer appears, which cuts breast cancer risk by about nine tenths, or to remove the other breast after a first cancer. Removing the ovaries protects against ovarian c...Open in Atlas Source
RNA: A working copy of a gene, made when the cell needs to use it. If DNA is the master library, RNA is the photocopy taken to the workshop.Open in Atlas Source
ROC-AUC, PR-AUC and time-dependent AUC: ROC-AUC is the chance a classifier scores a random positive above a random negative; PR-AUC focuses on the positives and is the better summary when they are rare; time-dependent AUC applies the idea to survival at a chosen horizon.Open in Atlas Source
Rokitansky-Aschoff sinus: Tiny pouches where the gallbladder lining pushes down into the muscle wall, common in gallbladders damaged by stones and inflammation. They matter in cancer because an early tumour that tracks down into these pouches behaves worse than one that stays on the...Open in Atlas Source
RxNorm drug nomenclature: RxNorm is the US National Library of Medicine's standard list of drug names and codes, linking brand, generic and dose forms so that the same medicine is recognised across records.Open in Atlas Source

S

Sakigake designation (Japan): Japan's fast lane for innovative medicines developed there first: a designated drug gets priority consultation, a six-month review instead of twelve, and a price premium, in return for early development in Japan.Open in Atlas Source
Salmonella Typhi carriage and gallbladder cancer: People who carry typhoid bacteria in their gallbladder for years have roughly four to five times the risk of gallbladder cancer. Laboratory work shows the bacterium can push already-damaged gallbladder cells towards cancer.Open in Atlas Source
Salpingo-oophorectomy: Removing the ovaries and fallopian tubes. Done for ovarian cancer, to prevent it in BRCA carriers, or to switch off oestrogen in breast cancer.Open in Atlas Source
Salvage therapy: Treatment given after the first treatment has failed or the cancer has come back, aiming to rescue the situation. It can still be curative (salvage surgery after organ-preservation fails) or a later line of palliation.Open in Atlas Source
Sarcoma (tissue type): Cancer of the body's connective and supporting tissues: bone, muscle, fat, cartilage, blood vessels, fibrous tissue. Rare (about 1% of adult cancers) but relatively common in children.Open in Atlas Source
Sarcoma in the radiotherapy field, and angiosarcoma of the treated breast: A sarcoma arising in tissue that was irradiated is uncommon, appears after about seven years or more, and is recognised by where it is rather than by any test. In the treated breast it most often takes the form of angiosarcoma, and because it can look like...Open in Atlas Source
Sarcomatoid differentiation (RCC): A spindle-cell change found in about 10% of kidney cancers that makes them aggressive and, unexpectedly, unusually responsive to immunotherapy.Open in Atlas Source
Sarcopenia: Sarcopenia is loss of muscle mass and strength. In cancer it predicts worse chemotherapy side-effects, more surgical complications and shorter survival, and it can hide in people who look a normal weight or overweight.Open in Atlas Source
Screening: Testing people who have no symptoms to catch cancer, or its precursors, early enough to cure. Proven for breast, cervical, colorectal and (in smokers) lung cancer; every test also finds some cancers that would never have caused harm.Open in Atlas Source
Screening survivors: where the UK, American and European answers differ: Three systems have built screening for survivors and they do not agree. England runs an organised programme with fixed ages and automatic referral; the United States issues a guideline and leaves the arranging to the patient; the Netherlands runs a national...Open in Atlas Source
Screening uptake: Uptake is the share of people invited to screening who actually take the test. It decides how much good a programme does, because a test nobody returns prevents nothing, and it is lower in more deprived areas, which turns a programme meant to close a gap in...Open in Atlas Source
SDH deficiency (SDHB immunohistochemistry loss): Loss of the succinate dehydrogenase enzyme, shown by a negative SDHB stain, marks a small family of tumours (some stomach GISTs, paragangliomas and phaeochromocytomas, a rare kidney cancer) that are often inherited, occur in young people, ignore imatinib an...Open in Atlas Source
Seamless, adaptive and Bayesian trial designs: Trial designs that change as data come in: merging phases so successful drugs move forward without pause, dropping arms or doses that are not working, adding new ones, and shifting randomisation toward what seems to help. Faster and more efficient, but they...Open in Atlas Source
Seasons of Survival: the 1985 essay that named the problem: A physician who had been treated for cancer wrote four pages in the New England Journal of Medicine in 1985 saying that the time after treatment was unmapped territory with hazards of its own. It is the paper the whole field dates itself from.Open in Atlas Source
Second cancers after radiotherapy: Radiotherapy can itself cause a new cancer in the treated area, typically ten to thirty years later. The risk is small for most adults but matters greatly for children and young adults.Open in Atlas Source
Second cancers after treatment: what the risk is, and what is done about it: A second cancer is a brand new cancer, not the first one coming back. Most are found by the ordinary routes, and some have a screening programme attached, which is the part worth asking about by name. The risk comes from three things that add together: the...Open in Atlas Source
Secondary malignancy (therapy-related cancer): A new, different cancer caused by the treatment of the first one: leukaemia after alkylating chemotherapy or PARP inhibitors, solid tumours in irradiated tissue decades later, and rarely T-cell lymphoma after CAR-T. Rare per patient, but it matters most for...Open in Atlas Source
Seed and soil hypothesis of metastasis (Paget): Stephen Paget asked in 1889 why breast cancer spread to some organs more than blood flow could explain, and answered that a travelling cancer cell (the seed) grows only where the organ (the soil) suits it. Ignored for most of a century, then confirmed: each...Open in Atlas Source
Segment IVb and V liver resection (versus wedge resection): Two ways of removing the piece of liver the gallbladder sits on during a gallbladder cancer operation: a wedge of about two centimetres around the gallbladder bed, or the whole of the two anatomical liver segments (IVb and V) that touch it. The larger opera...Open in Atlas Source
Segmental chromosomal aberrations and ploidy (neuroblastoma): In a child's neuroblastoma the pattern of chromosome damage is a crystal ball: tumours that have gained or lost whole chromosomes tend to regress or be cured, tumours with broken segments (11q loss, 1p loss, 17q gain) or with MYCN amplified relapse, and the...Open in Atlas Source
Segmentectomy (sublobar resection): Removing only a segment or wedge of a lung lobe rather than the whole lobe, sparing breathing capacity.Open in Atlas Source
Selective oestrogen receptor degrader (SERD): Drugs that do not just block the oestrogen receptor but mark it for destruction, so the cancer cell loses the receptor altogether. The new oral versions work even when the receptor has mutated (ESR1) to escape older hormone pills.Open in Atlas Source
Self-supervised pretraining (SSL): Self-supervised pretraining teaches a model from unlabelled data by hiding part of each example and asking it to predict the hidden part, so no expert labels are needed.Open in Atlas Source
Sensitivity and specificity: Sensitivity is the share of people with the disease a test catches; specificity is the share of healthy people it correctly clears. No test scores 100% on both, and for screening the trade-off decides how many false alarms you get.Open in Atlas Source
Sentinel node biopsy: Finding and removing the first one or two lymph nodes a tumour drains to, to see whether cancer has spread, instead of removing the whole nodal basin.Open in Atlas Source
Seroma after breast surgery: A collection of clear fluid under the wound or in the armpit after breast or lymph node surgery. It is common, it is not an infection, and it can be drained with a needle if it is uncomfortable, though it often comes back and settles on its own.Open in Atlas Source
Serrated pathway: The serrated pathway is the second route to bowel cancer, running not through the familiar mushroom-shaped polyp but through flat, pale, saw-toothed lesions that are easy to miss at colonoscopy and rarely bleed. It accounts for about three in ten bowel canc...Open in Atlas Source
Sexual function, fertility and body image after bowel cancer: Pelvic surgery and radiotherapy can affect the nerves and tissues that control erections, ejaculation, vaginal comfort and sensation, and pelvic radiotherapy often causes infertility and an early menopause. NICE asks teams to raise altered sexual function b...Open in Atlas Source
SF3B1 mutation: SF3B1 is a splicing gene whose mutation makes the marrow produce red cells with iron-stuffed mitochondria (ring sideroblasts); in myelodysplastic syndrome it defines a low-risk subtype with anaemia that responds to luspatercept, whereas in CLL and uveal mel...Open in Atlas Source
Side effect versus adverse event: An adverse event is anything bad that happens to a patient during a trial, whether or not the drug caused it; a side effect is a harm the drug is known to cause. Trial tables list adverse events and then judge which were treatment-related.Open in Atlas Source
Sidedness (left vs right colon): Where in the colon a tumour starts changes its biology and which drugs work. Left-sided tumours respond to EGFR antibodies; right-sided ones do not.Open in Atlas Source
Siewert classification (GEJ tumours): A way of classifying cancers at the junction of the oesophagus and stomach by where their centre sits, which decides whether they are treated as oesophageal or gastric.Open in Atlas Source
Signalling pathway: A chain of proteins that passes a message from the cell surface to the nucleus, each one switching on the next like a relay race. Cancer drugs try to break a link in the chain.Open in Atlas Source
Simple cholecystectomy: The standard operation to remove the gallbladder, almost always by keyhole surgery for gallstones. When a cancer is found in the removed gallbladder it is also the first, and for the earliest tumours the only, cancer operation.Open in Atlas Source
Single-arm trial: A trial where everyone gets the new drug and there is no comparison group; success is judged by the share of tumours that shrink and for how long. Fast and small, it underpinned accelerated approvals for larotrectinib, sotorasib, tarlatamab and most CAR-T p...Open in Atlas Source
Single-cell and transcriptome foundation models: UCE, GeneCompass, BulkFormer, BulkRNABert: These are transformer models pretrained on expression profiles: UCE and GeneCompass on tens of millions of single cells, BulkFormer and BulkRNABert on bulk tumour and tissue transcriptomes.Open in Atlas Source
Single-cell RNA sequencing (scRNA-seq, 10x Chromium): Single-cell RNA sequencing measures gene expression one cell at a time, revealing the cell types inside a tumour that bulk sequencing averages away.Open in Atlas Source
Skin cancer after an organ transplant: The drugs that keep a transplanted organ alive let skin cancers grow, and they grow differently: faster, in numbers, and far more likely to spread. This group is large, it is getting larger as transplant recipients live longer, and almost every trial of the...Open in Atlas Source
Skin cancer after cancer treatment: Skin cancer is the commonest second cancer after almost any treatment, and the commonest one left out of the counts, because registries record non-melanoma skin cancers inconsistently or not at all. Most are basal cell carcinomas, most are curable when trea...Open in Atlas Source
Skin grafts and flaps after skin cancer surgery: Two ways of closing a hole in the skin that is too big to stitch. A graft is a thin sheet of skin taken from somewhere else and laid over the wound, which means a second wound where it came from. A flap is skin from right beside the wound, moved across whil...Open in Atlas Source
Skin-directed therapy in mycosis fungoides: creams, light and small radiotherapy fields: Early mycosis fungoides is treated on the skin, not through the bloodstream. Steroid creams, a chemotherapy gel, ultraviolet light cabinets and very small doses of radiotherapy control it for years, and chemotherapy at this stage does harm without benefit.Open in Atlas Source
Small molecule drug: A small molecule drug is a chemically made medicine small enough to slip inside cells, so it can usually be taken as a tablet.Open in Atlas Source
Small-cell lung cancer transcription-factor subtypes (SCLC-A, SCLC-N, SCLC-P, SCLC-I) and SLFN11: Small-cell lung cancer has looked like one disease for fifty years; RNA profiling now splits it by the master transcription factor in charge (ASCL1, NEUROD1, POU2F3, or none with an inflamed signature), and these groups, plus the DNA-damage protein SLFN11,...Open in Atlas Source
SMART design (sequential multiple assignment randomised trial): A SMART trial randomises patients once at the start and again at a decision point, such as after the first scan or a residual disease test, to compare whole treatment strategies rather than single drugs.Open in Atlas Source
SMCC (thioether, non-cleavable): SMCC is the non-cleavable thioether linker in Kadcyla: the payload is freed only when the whole antibody is digested, so nothing leaks to neighbours.Open in Atlas Source
Smouldering myeloma / MGUS: Early plasma-cell conditions with no organ damage; most never progress, but high-risk smouldering disease is now sometimes treated.Open in Atlas Source
SN-38: SN-38 is the active form of the chemotherapy irinotecan and the payload of sacituzumab govitecan. It blocks topoisomerase I so DNA breaks during copying, but it kills cells only at nanomolar concentrations, so the ADC carries roughly eight copies per antibo...Open in Atlas Source
Software as a medical device (SaMD): Software as a medical device is software that is itself the medical device, such as a program that predicts a diagnosis or a treatment response, and is regulated like one.Open in Atlas Source
Sokal and ELTS risk scores (chronic myeloid leukaemia): Sokal and ELTS are arithmetic from the first blood count: age, spleen size, platelets and blast percentage at diagnosis sort chronic myeloid leukaemia into low, intermediate and high risk, and high-risk patients are the ones more likely to be started on a s...Open in Atlas Source
Somatic mutation theory of cancer: The standard account: cancer begins when a single body cell picks up mutations in the genes that control growth, and its descendants inherit them. It explains why carcinogens are mutagens, why cancer risk runs in some families and why drugs aimed at a mutat...Open in Atlas Source
Somatic mutations from exome and genome sequencing (WXS, WGS): Somatic mutations are the DNA changes a tumour acquired during life; they are read from exome (protein-coding) or whole-genome sequencing of tumour and matched normal tissue.Open in Atlas Source
Spatial autocorrelation (Moran's I): Spatial autocorrelation means that nearby spots in a tissue section tend to have similar values; Moran's I is the standard number for how strong that tendency is.Open in Atlas Source
Spatial transcriptomics platforms (Visium HD, Xenium, MERFISH, CosMx, CODEX): Spatial platforms measure RNA or protein while keeping each measurement's position on the tissue slide, so cell types and gene programmes can be mapped onto the tumour's architecture.Open in Atlas Source
Spatially aware clustering (SpaGCN, KNN smoothing): Spatially aware clustering groups the spots of a tissue section into domains using both what they express and where they sit, so the domains are contiguous regions rather than scattered spots.Open in Atlas Source
Spearman rank correlation: Spearman's rho measures how well the ranking of one variable matches the ranking of another, from minus one to plus one, ignoring the actual values.Open in Atlas Source
Spread through air spaces (STAS): Clusters of tumour cells found floating in the air sacs beyond the edge of the main tumour. The 2021 WHO classification recognised it as a real prognostic feature rather than an artefact of cutting the specimen, and it argues against taking out only part of...Open in Atlas Source
Squamous cell carcinoma: A carcinoma arising from the flat, layered cells that line surfaces exposed to wear: skin, mouth, throat, oesophagus, cervix, the larger airways. Often linked to tobacco, sun or HPV.Open in Atlas Source
Squamous cell carcinoma vs adenocarcinoma of the oesophagus: Oesophageal cancer is two different diseases in one organ: squamous cell carcinoma (upper/mid oesophagus, tobacco and alcohol, dominant in Asia) and adenocarcinoma (lower oesophagus, reflux and obesity, dominant in the West).Open in Atlas Source
SS18::SSX fusion (synovial sarcoma): Every true synovial sarcoma carries a fusion between the SS18 gene on chromosome 18 and an SSX gene on the X chromosome; finding it by FISH, RNA sequencing or a newer antibody stain confirms a diagnosis that pathologists otherwise struggle with, and it also...Open in Atlas Source
Stable disease: The tumours have neither shrunk enough to count as a response nor grown enough to count as progression. For a slow cancer or a well-tolerated drug, months of stability can be a real benefit.Open in Atlas Source
Stage: How far a cancer has spread, from stage I (small and confined) to stage IV (spread to distant organs). Stage is the single strongest guide to treatment and prognosis.Open in Atlas Source
Stage shift: Stage shift means finding more cancers early and fewer late; it is the measurable goal of screening.Open in Atlas Source
Staging a lymphoma of the stomach or bowel: A lymphoma that starts in the stomach or bowel is staged by how deep it goes into the wall and how far along the lymph node chain it has travelled, not only by how many node regions are involved. The depth is measured by endoscopic ultrasound, and it decide...Open in Atlas Source
STAMPEDE's arms, and what each one answered: One British trial, running since 2005, has asked nine separate questions about prostate cancer treatment by adding new arms as the answers came in. Four of them changed what men are offered, and five did not.Open in Atlas Source
Standard of care: The standard of care is the treatment that guidelines and experts currently consider the best-proven option.Open in Atlas Source
Standardised uptake value (SUV): The standardised uptake value (SUV) is a number for how brightly a spot lights up on a PET scan.Open in Atlas Source
STAR and Salmon (RNA-seq alignment and quantification): STAR lines sequencing reads up against the genome and Salmon estimates how much of each transcript is present; they are the two most common first steps of an RNA-seq pipeline.Open in Atlas Source
State biomarker testing coverage laws: A wave of US state laws, starting in 2021, that require insurers regulated by the state and often Medicaid to pay for the tumour and inherited gene tests that decide which targeted drug a patient should get.Open in Atlas Source
Statistical power, sample size and re-estimation: Before a trial starts, statisticians work out how many patients, or how many deaths or relapses, are needed to detect the benefit they hope for; an adaptive trial can check that guess part way through and enlarge itself if the guess was wrong.Open in Atlas Source
Statistical significance (P values, alpha, multiplicity): A result is 'statistically significant' when it would be unlikely (usually under 5%) to arise by chance if the treatment did nothing. It is a threshold, not a measure of benefit size: a tiny gain can pass it in a huge trial and a large one can miss it in a...Open in Atlas Source
Stem cell: A cell that can both copy itself indefinitely and produce the specialised cells of a tissue. Cancers may be sustained by a small population of stem-like cells that survive treatment and regrow the tumour.Open in Atlas Source
Stem cell transplant in lymphoma: what it is still for: An autologous transplant is very high-dose chemotherapy followed by the patient's own stored stem cells to rescue the bone marrow. CAR-T and BTK inhibitors have taken over several of its old jobs, but it is still the right answer in a shrinking list of situ...Open in Atlas Source
Stent or bypass for jaundice: the choice: When the cancer blocks the bile duct, a stent placed by endoscope or through the skin is the usual way to relieve jaundice; a surgical bypass is reserved for people already having an operation or when a stent cannot be placed.Open in Atlas Source
Stenting (biliary, oesophageal, airway): Placing a small mesh or plastic tube to hold open a duct or passage that a tumour is squeezing shut, relieving jaundice, swallowing difficulty or breathlessness.Open in Atlas Source
Step-up dosing (T-cell engagers): Starting a bispecific T-cell engager (teclistamab, glofitamab, epcoritamab, tarlatamab) at a tiny dose and increasing it over the first week, so T cells are switched on gradually and the fever-and-low-blood-pressure reaction (cytokine release syndrome) stay...Open in Atlas Source
Stepped-wedge design: In a stepped-wedge trial every hospital or region eventually switches to the new approach, but the order in which they switch is randomised, so the periods before and after each switch can be compared fairly.Open in Atlas Source
Stereotactic body radiotherapy (SBRT / SABR): A course of one to five large, pinpoint-accurate radiation doses that destroy a tumour outside the brain almost like surgery, for patients who cannot or prefer not to have an operation. It is standard for inoperable early lung cancer and the backbone of oli...Open in Atlas Source
Stereotactic radiosurgery (SRS): A single high dose of radiation delivered to a brain tumour or metastasis by beams converging from all sides, so the target gets a destructive dose while the surrounding brain gets little; no scalpel is involved despite the name. It treats metastases up to...Open in Atlas Source
STK11 / KEAP1 co-mutations: Two genes whose loss, often alongside a KRAS mutation, makes lung cancer 'cold' to immunotherapy and shortens survival on standard treatment. They are the reason two KRAS-mutant lung cancers can behave completely differently.Open in Atlas Source
Stoma (colostomy, ileostomy, urostomy): An opening made in the abdominal wall so bowel or urine empties into a bag; may be temporary while a join heals, or permanent when the rectum, anus or bladder has been removed.Open in Atlas Source
Stopping smoking: The single largest thing anyone can do about lung cancer, before or after a diagnosis. Risk falls the longer it is since the last cigarette and falls further the younger someone stops, and the benefit is large even for people who have smoked for decades.Open in Atlas Source
Stratified randomisation, allocation concealment and minimisation: Randomisation is done by computer and often within groups (by stage, by biomarker, by region) so that each arm gets a fair share of the patients who matter most, and nobody can steer a particular patient to a particular arm.Open in Atlas Source
Stress urinary incontinence: Leaking urine when you cough, sneeze, lift or stand up, because the muscle that holds it in has been weakened.Open in Atlas Source
Stroma-rich and desmoplastic tumours in molecular data: Some cancers, pancreatic cancer above all, are mostly dense scar-like stroma with few tumour cells; their bulk molecular profiles are dominated by that stroma.Open in Atlas Source
Subgroup analysis (forest plots): Splitting a trial's patients into groups (by age, sex, biomarker, region) to see whether the treatment worked the same in each. Shown as a forest plot. Genuine differences are rare and most striking subgroup results are noise, so they need confirmation.Open in Atlas Source
Sublobar resection (segmentectomy and wedge): Removing part of a lobe of the lung rather than the whole lobe. For small peripheral tumours with lymph nodes shown to be clear, two randomised trials found it as good as taking the whole lobe, and it leaves more lung behind.Open in Atlas Source
Sulfo-SPDB (disulfide): Sulfo-SPDB is a hindered disulfide linker that is stable in blood but is cut by the reducing environment inside cells, then converted to a membrane-crossing form.Open in Atlas Source
Sun protection after a skin cancer diagnosis: Not a lecture but a short list: shade between 11am and 3pm, clothes and a wide-brimmed hat, SPF 30 or more with four or five UVA stars used generously and reapplied, never a sunbed, and a vitamin D supplement in winter because the rest of the list reduces i...Open in Atlas Source
Superior vena cava obstruction: A tumour or clot blocks the large vein that returns blood from the head and arms to the heart, so the face, neck and arms swell and the veins on the chest stand out. It is frightening and looks urgent, but it is usually treatable and rarely an immediate eme...Open in Atlas Source
Supplementary protection certificate (EU): The EU's version of patent term restoration: up to five extra years of protection for a medicine to make up for the years spent in trials and review, so that a cancer drug gets about fifteen years of protected sales after approval, plus six months for paedi...Open in Atlas Source
Surgical morbidity and postoperative complications: The harms of an operation itself: complications (leaks, infections, bleeding, pneumonia), time in hospital, and deaths within 30 or 90 days. Big cancer operations carry real risk, which is weighed against their chance of cure and drives the search for less...Open in Atlas Source
Surrogate endpoint: A quicker, easier measurement used as a stand-in for what really matters. Tumour shrinkage or delayed growth stands in for living longer, on the assumption, not always true, that one leads to the other.Open in Atlas Source
Surrogate endpoint validation: which stand-ins have earned trust: A surrogate endpoint only deserves trust if trials have shown that moving it moves the outcome that matters, in that disease and for that kind of drug; some stand-ins have passed that test, several have not, and the record differs endpoint by endpoint.Open in Atlas Source
Surveillance intervals after polypectomy: After polyps are removed, the date of your next colonoscopy is set by what was found, not by habit. In the UK, most people go back to routine screening; only those with several premalignant polyps or one advanced one are brought back at three years, and peo...Open in Atlas Source
Survival outcomes as time plus event (OS, PFS): A survival outcome is recorded as two numbers per patient: how long they were followed, and whether the event (death, or progression) happened by then.Open in Atlas Source
Symptom control in advanced gallbladder cancer: pain, ascites and nutrition: Advanced gallbladder cancer causes pain under the right ribs, fluid in the abdomen and weight loss. Pain is treated with opioids and, for pain that spreads to the back, a nerve block of the coeliac plexus; fluid is drained by needle or a permanent tunnelled...Open in Atlas Source
Synthetic lethality: Two genes where losing either alone is fine but losing both kills the cell. Cancers that have lost one become vulnerable to drugs against the other.Open in Atlas Source
Systemic versus local therapy: Local therapy (surgery, radiotherapy) treats one place in the body; systemic therapy (drugs given by mouth or vein) travels through the bloodstream and treats the whole body, including cancer cells too small to see.Open in Atlas Source

T

T cell: The immune system's trained assassins. Each T cell recognises one specific target displayed on a cell's surface and, if the cell is infected or cancerous, kills it. Most immunotherapy is about unleashing them.Open in Atlas Source
t(11;14), cyclin D1 and SOX11: The t(11;14) translocation parks the cyclin D1 gene next to the antibody gene's accelerator, flooding the cell with a protein that pushes it through division; a brown nuclear stain for cyclin D1 (plus SOX11) is how mantle cell lymphoma is confirmed, and in...Open in Atlas Source
T-cell exhaustion and CAR-T persistence: Immune T cells that have been fighting too long become 'exhausted': sluggish, covered in inhibitory receptors, unable to kill. It limits both the patient's natural anti-tumour response and how long engineered CAR-T cells keep working (persistence).Open in Atlas Source
T030 (belotecan derivative): T030 is the belotecan-derived topoisomerase payload in sacituzumab tirumotecan, designed to be less affected by the pumps that eject SN-38.Open in Atlas Source
T2a versus T2b gallbladder cancer (peritoneal side versus hepatic side): Two labels for a gallbladder cancer that has grown through the muscle layer but is still inside the gallbladder. T2a sits on the free side facing the abdominal cavity; T2b sits on the side pressed against the liver, spreads to nodes and vessels more often a...Open in Atlas Source
TACE (transarterial chemoembolisation): Threading a catheter into the artery feeding a liver tumour and injecting chemotherapy plus particles that block the blood supply, starving and poisoning it at once.Open in Atlas Source
TARE / SIRT (radioembolisation with yttrium-90): Injecting tiny radioactive glass or resin beads into the liver's artery so they lodge in the tumour and irradiate it from inside.Open in Atlas Source
Targeted axillary dissection: When chemotherapy is given before surgery, the surgeon marks the lymph node that was known to contain cancer with a clip before treatment starts, then removes that exact node afterwards along with the sentinel nodes. It is the difference between missing lef...Open in Atlas Source
Targeted lung health check: The NHS appointment that decides whether you are offered a lung scan. People aged 55 to 74 whose GP record shows they smoke or used to are asked about their breathing, health and smoking; a risk score then decides who gets a low-dose CT scan, often in a mob...Open in Atlas Source
Targeted panel sequencing: A targeted panel sequences only a chosen set of a few hundred cancer genes, deeply and cheaply, which is what most hospitals run on tumours today.Open in Atlas Source
Targeted therapy: Drugs designed to hit a specific molecule the cancer depends on, usually a protein made by a mutated or amplified gene, while leaving normal cells relatively alone. The tumour is tested first to see whether it carries the target.Open in Atlas Source
Taxanes (paclitaxel, docetaxel, nab-paclitaxel): Chemotherapy drugs originally from the yew tree that freeze the cell's internal scaffolding (microtubules) so it cannot divide. Used in breast, lung, ovarian, prostate, gastric and head and neck cancers; their main lasting side effect is nerve damage in the...Open in Atlas Source
TCGA barcode: A TCGA barcode such as TCGA-A1-A0SB-01A-11R-A144-07 encodes the project, tissue source site, patient, sample type, vial, portion, analyte, plate and centre, and is the key that joins one patient's data files.Open in Atlas Source
TCGA open versus controlled data tiers: TCGA data comes in two tiers: open files (gene expression, somatic mutations, clinical tables, slide images) anyone can download, and controlled files (raw reads, germline variants) that need dbGaP approval.Open in Atlas Source
Template mapping biopsy (transperineal template prostate mapping): A thorough biopsy done under general anaesthetic through the skin behind the scrotum, using a grid to sample the whole prostate systematically. It gives the most complete picture available short of removing the gland, and for that reason it is used as the y...Open in Atlas Source
TERT promoter mutation: A mutation that keeps the cell's immortality enzyme switched on. In thyroid cancer, having it alongside BRAF marks the tumours most likely to spread and resist iodine.Open in Atlas Source
Tertiary lymphoid structures (TLS): Tertiary lymphoid structures are organised clusters of immune cells that form inside tumours and resemble small lymph nodes; their presence is linked to better immunotherapy outcomes.Open in Atlas Source
Tetrapeptide GGFG (maleimide-GGFG-aminomethyl): The GGFG tetrapeptide (glycine-glycine-phenylalanine-glycine) is the tether between antibody and payload in Enhertu and Dato-DXd. Lysosomal cathepsins cut it inside the cancer cell, and it holds in circulation well enough to allow eight payloads per antibod...Open in Atlas Source
The Brigham and Women's Hospital staging system, and why squamous cell carcinoma has two: The anatomical staging systems put almost every squamous cell carcinoma in one or two categories, so they cannot pick out the few that will spread. A Boston group built an alternative that counts four risk factors instead of measuring the tumour, and it fin...Open in Atlas Source
The CAR-T pathway in lymphoma: referral, apheresis, bridging and the waiting: CAR-T is not a prescription but a manufacturing process. Cells are collected from the patient, sent away to be engineered, and returned three to five weeks later. What happens during that wait decides whether the treatment is given at all.Open in Atlas Source
The Common Rule (45 CFR 46): The US rules that require an ethics committee to approve research on people and require informed consent, written in 1991 and rewritten in 2018 so that a single committee can oversee a multi-site cancer trial and patients can give broad consent for future u...Open in Atlas Source
The founding of the National Coalition for Cancer Survivorship, and the word survivor: Twenty-three people met in Albuquerque in October 1986 and set out to replace the phrase "cancer victim" with "cancer survivor". The definition they chose, a survivor from the day of diagnosis for the rest of life, is the one the National Cancer Institute u...Open in Atlas Source
The germinal centre: why lymphoma starts where antibodies are made: To make a better antibody, a B cell has to deliberately damage its own DNA while dividing fast, with its safety checks switched off. Most B-cell lymphomas are cells that went into that process and never came out of it properly.Open in Atlas Source
The growth pattern on a basal cell carcinoma report: nodular, superficial, infiltrative, basosquamous: Basal cell carcinomas are sorted by the shape they grow in, and the shape decides how much skin has to be taken and who does it. Nodular and superficial patterns are low risk; infiltrating, sclerosing or morphoeic, and micronodular patterns are high risk be...Open in Atlas Source
The Hodgkin microenvironment: when the cancer cell is the minority: In Hodgkin lymphoma most of the swollen lymph node is not cancer. The cancer cells are scattered giants that make up a small fraction of the tissue; everything else is immune cells the tumour has recruited and put to work.Open in Atlas Source
The lymphoma regimen alphabet: R-CHOP, pola-R-CHP, DA-EPOCH-R, ABVD, BEACOPP and the rest: Lymphoma treatment is written in acronyms, one letter per drug. This entry spells out the ones a patient will see on a chart or a consent form, and says which disease each belongs to.Open in Atlas Source
The margin in skin cancer surgery: When a skin cancer is cut out, the surgeon takes a rim of normal-looking skin around it, because the cancer reaches further than the eye can see. Four millimetres is the usual rim, and it was chosen by measuring how far tumours actually spread, not by agree...Open in Atlas Source
The National Cancer Survivorship Initiative in England, and the Recovery Package: England ran a national programme on life after cancer from 2007. It produced a named bundle of four things every patient should get at the end of treatment, and a 2013 report that measured how rarely they got them.Open in Atlas Source
The next skin cancer: second primaries after a keratinocyte cancer: The likeliest thing to happen after a basal cell or squamous cell carcinoma is not that this one comes back. It is that you get a different one somewhere else, because the whole area of skin took the same ultraviolet damage. The published three-year figures...Open in Atlas Source
The scar on the face after skin cancer surgery: Every skin cancer operation leaves a scar, and on a face it is the part people mind most. It is at its most noticeable early on, red and raised, and it settles over months rather than weeks; the NHS says most scars fade over up to two years or more. Massage...Open in Atlas Source
The subtype and grade on a cutaneous squamous cell carcinoma report: A squamous cell carcinoma report carries two separate things: a subtype, which is the shape the tumour grows in, and a grade, which is how much it still looks like normal skin. Most are of no special type and well differentiated. Four subtypes and the poorl...Open in Atlas Source
The surveillance schedule, and the evidence that routine scans do not find relapse first: Most people expect regular scans after lymphoma treatment and are unsettled when they are not offered. The evidence is that in most lymphomas relapse is found because the person notices something, not because a scan catches it, and that finding it by scan d...Open in Atlas Source
The two lymphoma classifications of 2022 (WHO-HAEM5 and ICC): Since 2022 there have been two reference classifications of lymphoma rather than one, published within months of each other by overlapping groups of experts. They agree about most diseases and disagree about a handful of names and boundaries, so the same bi...Open in Atlas Source
The UK very high risk breast screening protocol after chest radiotherapy: England runs a named screening programme for women who had radiotherapy to breast tissue when young, with exact ages and tests set out in its own documents. Surveillance begins at 25 or 30 depending on your age when irradiated, or eight years after the radi...Open in Atlas Source
The WHO classification of breast tumours, and what the 6th edition changed: The book that decides what a breast tumour is called. Its fifth edition (2019) is the one UK reports are written against in 2026; its sixth edition was set out in April 2026, in the editorial board's own summary of it, and changed the vocabulary, the HER2 r...Open in Atlas Source
Theranostics: Using the same targeting molecule for a diagnostic scan and a therapy, so you treat exactly what you can see.Open in Atlas Source
Therapeutic index (therapeutic window): The gap between the dose that works and the dose that harms. Classic chemotherapy has a narrow window (the dose that kills the tumour nearly kills the patient); a wider window is the whole point of targeted drugs, ADCs and immunotherapy.Open in Atlas Source
Thrombocytopenia: Too few platelets, the blood cells that form clots, caused by chemotherapy or by the cancer in the marrow. Mild cases cause bruising; severe cases (under 10-20 × 10⁹/L) risk serious bleeding and need platelet transfusions.Open in Atlas Source
Thyroid cancer after neck radiotherapy, and whether to look for it: The thyroid is among the most radiation-sensitive tissues there is, and neck or upper chest radiotherapy raises the risk of thyroid cancer for decades. Whether to look for it is genuinely unsettled: the international guideline panel compared ultrasound agai...Open in Atlas Source
Thyroidectomy: Removing all (total) or half (hemi-) of the thyroid gland, after which thyroid hormone tablets replace its function.Open in Atlas Source
Tile and patch encoding of slides: A whole slide is cut into thousands of small square tiles, each tile is turned into a vector by an image model, and the vectors are pooled to describe the slide.Open in Atlas Source
Time to progression (TTP) and time to next treatment (TTNT): A family of 'time to X' endpoints: how long until the cancer grows (TTP, which unlike PFS ignores deaths), until the patient needs another treatment (TTNT), until it spreads (metastasis-free survival), or until symptoms worsen. Each captures something patie...Open in Atlas Source
Tissue organisation field theory (Sonnenschein and Soto): Carlos Sonnenschein and Ana Soto argue that cancer is a disease of tissue architecture, not of single cells: carcinogens disrupt the conversation between a tissue's supporting stroma and its lining cells, and disordered growth follows as in a wound or an em...Open in Atlas Source
Tissue-of-origin signal in tumour data: A tumour's molecular profile is dominated by the organ it came from, so a model can look impressive by recognising the organ and must be judged against a baseline that knows only that.Open in Atlas Source
TNM 9: what changed in lung cancer staging: Lung cancer has been staged by the ninth edition of TNM since 1 January 2025. The T categories are unchanged; N2 was split into N2a and N2b by how many mediastinal node stations are involved, M1c was split by how many organ systems carry metastases, and sev...Open in Atlas Source
TNM staging: TNM staging is the universal system describing tumour size (T), lymph node spread (N), and distant metastasis (M).Open in Atlas Source
TNM staging for prostate cancer, and what changed in the 9th edition: The anatomical stage of prostate cancer: how far the tumour has grown (T), whether it is in the pelvic lymph nodes (N) and whether it has spread further (M). UK reports use the 8th edition; the 9th, recommended from January 2026, leaves the prostate categor...Open in Atlas Source
Tobacco 21: Since December 2019 it has been illegal across the United States to sell tobacco or vaping products to anyone under 21, a rule that started in one Massachusetts town and spread state by state, aimed at the years when most smokers start.Open in Atlas Source
Tokenisation (genes, tiles and sequence as tokens): Tokenisation is how raw input is chopped into the discrete pieces a transformer reads: words into subwords, a slide into tiles, an expression profile into genes ranked or binned by level.Open in Atlas Source
Topoisomerase II inhibitors and the shorter latency: Etoposide and the anthracyclines can cause a leukaemia too, but a different one: it arrives after about two years rather than six, it starts as acute leukaemia without a myelodysplastic phase, and it carries a balanced break in a chromosome rather than a mi...Open in Atlas Source
Topoisomerase-I inhibitor payloads: Topoisomerase-I inhibitor payloads are the payload class behind Enhertu, Trodelvy and Dato-DXd: poisons that trap the enzyme that untwists DNA, so dividing cells break their own DNA.Open in Atlas Source
Total mesorectal excision (TME): The standard rectal cancer operation: the rectum is removed together with its surrounding fatty envelope (the mesorectum) in one intact package, which is where local recurrences used to come from.Open in Atlas Source
Total neoadjuvant therapy (TNT, rectal cancer): Giving all the chemotherapy and radiotherapy for rectal cancer before surgery rather than splitting it around the operation. It improves completion of chemotherapy, shrinks more tumours completely, and makes avoiding surgery possible for some patients.Open in Atlas Source
Toxicity grade: A 1 to 5 severity scale for side effects: grade 1 mild, grade 2 moderate, grade 3 severe and needing intervention, grade 4 life-threatening, grade 5 fatal. Trials report the percentage of patients with grade 3 or worse.Open in Atlas Source
TP53-mutated (p53-abnormal): Loss of the p53 'guardian of the genome', the most commonly mutated gene in cancer. In blood cancers and several solid tumours a TP53 mutation marks the highest-risk group, resistant to chemotherapy and hard to treat.Open in Atlas Source
TPM, FPKM and raw counts (expression units): Raw counts are how many sequencing reads hit each gene; TPM and FPKM rescale them for gene length and sequencing depth so genes and samples can be compared, and log2 TPM is the usual model input.Open in Atlas Source
Train, validation and test split discipline: Data is divided into a training set the model learns from, a validation set used to choose settings, and a test set touched once at the end; using the test set to make choices turns it into a second validation set.Open in Atlas Source
Transfer learning and the low-label regime: Transfer learning reuses what a model learned on one task or dataset to do better on a related task with few labels, the situation for almost every cancer outcome.Open in Atlas Source
Transformation of an indolent lymphoma: A slow-growing lymphoma can change into a fast-growing one. It usually announces itself as one node growing much faster than the others, a sudden rise in lactate dehydrogenase, or new fevers and weight loss in somebody who has been stable for years. It is t...Open in Atlas Source
Transformation: when a slow lymphoma turns into a fast one: An indolent lymphoma can change into an aggressive one, usually by acquiring new genetic faults in the same clone. It is the commonest reason a person who has been well for years becomes unwell quickly, and it is treated as the aggressive disease rather tha...Open in Atlas Source
Transformer and attention: A transformer is a neural network that turns its input into a sequence of tokens and lets every token weigh every other through attention, the architecture behind language models and most new biology models.Open in Atlas Source
Transplant or CAR-T at second line in diffuse large B-cell lymphoma: If a large B-cell lymphoma comes back within a year of first treatment, two trials found that engineered T cells worked better than salvage chemotherapy followed by a transplant of the person's own stem cells, and a third trial of a different T-cell product...Open in Atlas Source
Transurethral resection of bladder tumour (TURBT): Shaving a bladder tumour away from the inside using a scope passed up the urethra. It is both the diagnosis and, for non-muscle-invasive cancer, the treatment.Open in Atlas Source
Trastuzumab cardiotoxicity: HER2 drugs can weaken the heart's pumping, usually reversibly, so heart function is checked every three months during treatment.Open in Atlas Source
Treatment at the local hospital or at a cell-therapy centre far from home: Most lymphoma chemotherapy is given at the nearest hospital, but engineered T-cell treatment is only given at a small number of approved centres, and it requires living near that centre for about a month with another adult present. The travel and the accomm...Open in Atlas Source
Treatment-induced bone loss: Thinning of the bones caused by switching off testosterone, which raises the risk of fractures.Open in Atlas Source
Trial lifecycle: from protocol to label: A trial moves through a fixed sequence: a written protocol, regulatory and ethics approval, public registration, opening sites and enrolling patients, independent monitoring while it runs, readout when enough events have happened, presentation and publicati...Open in Atlas Source
Trial protocol and statistical analysis plan: The protocol is the rulebook a trial is run by, written before it starts: who can join, what they get, what is measured and when, and how the answer will be calculated; the statistical analysis plan spells out the last part in detail so nobody can choose th...Open in Atlas Source
Trial registration and results reporting (ClinicalTrials.gov, EU CTR): Every trial is supposed to be listed in a public registry before it enrols anyone, with its design and primary endpoint on record, and to post its results within a year of finishing, so that trials cannot quietly disappear or change what they were measuring...Open in Atlas Source
Triple-negative breast cancer trials open today (registry snapshot and UK sites): Every phase 2 or 3 drug trial that was recruiting, about to open or still running for triple-negative breast cancer on ClinicalTrials.gov in September 2026, with the hospitals in the United Kingdom that take part named where the registry lists them.Open in Atlas Source
TRIPS Agreement and the Doha Declaration: The 1994 world trade treaty that obliged every member country to grant twenty-year patents on medicines, and the 2001 declaration confirming that countries may still issue compulsory licences and protect public health; together they set the global terms on...Open in Atlas Source
TSH suppression: Giving slightly more thyroid hormone than the body needs after thyroid cancer surgery, to switch off the pituitary signal that could feed leftover cancer cells.Open in Atlas Source
TTF-1 and p40 (how lung histology is decided): The two stains that decide whether a poorly differentiated lung cancer is called adenocarcinoma or squamous cell carcinoma. TTF-1 positive with p40 negative means adenocarcinoma; p40 positive with TTF-1 negative means squamous. The answer decides whether th...Open in Atlas Source
Tubulin inhibitor payloads: Tubulin inhibitor payloads were the first generation of modern ADC payloads: drugs that jam the cell's scaffolding so it cannot divide. Nerve and eye side effects are typical.Open in Atlas Source
Tumour bed boost: An extra dose of radiotherapy aimed at the small area the lump came from, given after the whole breast has been treated. It cuts the chance of the cancer coming back in that breast by about a third, does not help anyone live longer, and triples the chance o...Open in Atlas Source
Tumour board (multidisciplinary team meeting): A tumour board is a meeting where doctors from different specialties review one patient's cancer together and agree a treatment plan.Open in Atlas Source
Tumour differentiation (well / moderately / poorly differentiated): How much the cancer cells still resemble the normal tissue they came from. Well-differentiated tumours look almost normal and tend to grow slowly; poorly differentiated ones have lost their identity and behave aggressively. It is the basis of grade.Open in Atlas Source
Tumour evolution (somatic evolution): A tumour changes over time as its cells acquire mutations and the fittest clones take over, which is why cancers relapse and resist treatment.Open in Atlas Source
Tumour hypoxia: Regions of a tumour that have outgrown their blood supply and are short of oxygen. They resist radiotherapy and some chemotherapy, and drive the tumour to become more aggressive.Open in Atlas Source
Tumour lysis syndrome (TLS): When a treatment kills cancer cells faster than the body can clear their contents, flooding the blood with potassium, phosphate and uric acid and injuring the kidneys and heart. Risk is highest in bulky CLL and high-count AML, which is why venetoclax starts...Open in Atlas Source
Tumour lysis syndrome in lymphoma: who is at risk, and rasburicase: When a large, fast-growing lymphoma breaks up quickly, the contents of the cells flood the blood and can stop the kidneys or the heart. It is predictable, preventable and is the reason the first days of treatment are given in hospital with fluids and blood...Open in Atlas Source
Tumour marker: A substance, usually a protein, that a tumour releases into the blood in measurable amounts. Rising or falling levels track whether the cancer is growing or responding, though they are rarely good enough for diagnosis on their own.Open in Atlas Source
Tumour markers (CEA, LDH, chromogranin, thyroglobulin): Substances released into the blood by some cancers that can be measured with a simple test, useful for tracking whether treatment is working or the cancer is coming back, but rarely good enough to diagnose or screen.Open in Atlas Source
Tumour mutational burden (TMB): How many mutations a tumour has. More mutations mean more targets for the immune system.Open in Atlas Source
Tumour proportion score (TPS): The PD-L1 score used in lung cancer: the percentage of tumour cells that stain positive.Open in Atlas Source
Tumour purity: Tumour purity is the fraction of cells in a sample that are actually cancer cells rather than normal, immune or stromal cells.Open in Atlas Source
Tumour size on a breast report, and why it differs from the scan: The size on the pathology report is the largest continuous lump of invasive cancer measured under the microscope, which is not the same as the size on the mammogram or the MRI. Separate deposits five millimetres or more apart are not added together, and the...Open in Atlas Source
Tumour suppressor gene: A gene whose normal job is to stop cells dividing or to make damaged cells die. Losing it removes a brake, so the cell can grow unchecked even without a stuck accelerator.Open in Atlas Source
Tumour-agnostic (tissue-agnostic) approval: A tumour-agnostic approval lets a drug be used for any cancer carrying a specific molecular feature, regardless of where it started.Open in Atlas Source
Tumour-associated macrophages (TAMs): Tumour-associated macrophages are immune cells that should eat cancer cells but are re-educated by the tumour to protect it instead. They are often the most abundant immune cell in a tumour.Open in Atlas Source
Tumour-infiltrating lymphocytes (TILs): Immune cells that have got inside the tumour. More of them means better outcomes in triple-negative breast cancer.Open in Atlas Source
Tumour-informed versus tumour-naive ctDNA assays: A tumour-informed blood test is built for one patient: the tumour is sequenced first and the test then hunts for that patient's own mutations in blood. A tumour-naive test uses the same fixed panel, often of methylation marks, for everyone, so it needs no t...Open in Atlas Source
Type 3c diabetes with pancreatic cancer: Pancreatic cancer or surgery to remove part or all of the pancreas can stop it making enough insulin and glucagon; the result is type 3c diabetes, which behaves differently from type 1 and type 2, usually needs tablets or insulin, and is best managed by a d...Open in Atlas Source
Tyrosine kinase inhibitor (TKI): Pills that block the on-switch enzyme (a kinase) that a particular cancer depends on: imatinib for CML, osimertinib for EGFR lung cancer, ibrutinib for CLL. Usually taken daily at home and continued as long as they work.Open in Atlas Source

U

Uberon anatomy ontology and the Cell Ontology: Uberon names anatomical structures (organs, tissues) and the Cell Ontology names cell types, each with a code, so that a tissue label or a cell-type annotation means the same thing across datasets.Open in Atlas Source
UK Data Protection Act 2018 and health data law: The UK's data law, which keeps the EU's GDPR in domestic form and adds NHS-specific rules, so that cancer registries and research can use patient records under a public-interest basis, patients can opt out of secondary uses, and a 2025 Act loosened the cons...Open in Atlas Source
Ulceration (melanoma): Loss of the skin surface over a melanoma under the microscope; a sign of aggressive biology that raises the stage.Open in Atlas Source
Ultra-processed food (NOVA group 4): Industrially formulated products made mostly from extracted or synthesised ingredients (soft drinks, packaged snacks, reconstituted meats, ready meals). High intake is linked with obesity and, in cohort studies, with more cancer, though the evidence is grad...Open in Atlas Source
Umbrella trial: An umbrella trial takes one cancer, tests every patient's tumour for a panel of markers, and routes each patient to the sub-study whose drug matches their marker, so several targeted drugs are tested at once under one roof.Open in Atlas Source
Uncertainty quantification and confidence gates: Uncertainty quantification attaches to each prediction an estimate of how much to trust it, so a system can report high confidence, low confidence or refuse.Open in Atlas Source
Undetectable MRD (uMRD / MRD-negative): The test for leftover cancer cells found none, down to the sensitivity of the assay (often one cell in 100,000 or a million). It is the deepest remission we can measure and is becoming a treatment goal and trial endpoint in blood cancers.Open in Atlas Source
Units of measurement ontology (UO): The Units of measurement ontology gives every unit (milligram per square metre, months, TPM) a code, so a number in a dataset says what it is a number of.Open in Atlas Source
Univariate Cox scores and time-dependent metrics: A univariate Cox model fits one gene at a time against survival and its z-score ranks genes by prognostic strength; the Breslow approximation is how the fit handles patients whose events fall on the same day.Open in Atlas Source
Unproven diet claims (alkaline, juice, 'anti-cancer' diets): Diets marketed as cancer cures or preventives with no supporting evidence: alkaline diets, juice cleanses, Gerson therapy, apricot kernels and the like. Some are merely useless; several have caused harm or led people to delay effective treatment.Open in Atlas Source
Urinary catecholamine metabolites (VMA and HVA): Neuroblastoma cells make adrenaline-type hormones and spill their breakdown products, VMA and HVA, into urine; a simple urine test supports the diagnosis in nine out of ten children, and falling levels after treatment or rising ones in follow-up track the t...Open in Atlas Source
US regulatory exclusivity periods: Separate from patents, US law gives an approved drug fixed periods during which the FDA will not approve a copy: five years for a new chemical, three for new clinical studies, seven for an orphan indication, twelve for a biologic, plus six months for paedia...Open in Atlas Source
Uveal melanoma prognostic markers (GNAQ/GNA11, monosomy 3, gene-expression class): Nearly all eye melanomas start with a mutation in GNAQ or GNA11, which is why skin-melanoma drugs do not work on them; what decides whether the tumour will spread to the liver is a second layer: loss of chromosome 3 with BAP1 mutation and a class 2 gene-exp...Open in Atlas Source

V

Vaccinations around lymphoma treatment: the ones to have first, and the ones not to have at all: Inactivated vaccines work best when they are given at least two weeks before immunosuppressive treatment begins, and live vaccines are generally not given to someone whose immune system is suppressed. Treatment that removes B cells blunts the response to va...Open in Atlas Source
Val-Ala dipeptide: The Val-Ala dipeptide linker is easier to manufacture and less prone to aggregation than valine-citrulline, and is used with PBD payloads.Open in Atlas Source
Variant allele frequency (VAF): The fraction of DNA reads carrying a mutation. Tells you how much of the sample is mutant and how clonal it is.Open in Atlas Source
Variant calling: Variant calling is the computational step that turns raw sequencing reads into a list of the DNA changes present in a tumour.Open in Atlas Source
Variant effect prediction: Variant effect prediction uses computation to guess whether a DNA change damages a protein or matters clinically, before or instead of laboratory evidence.Open in Atlas Source
Variant of uncertain significance (VUS): A variant of uncertain significance (VUS) is a genetic change that has been found but nobody yet knows whether it matters.Open in Atlas Source
Variation between clinicians in drawing the radiotherapy target: Before a radiotherapy plan can be made, a doctor draws the tumour and the organs around it on the planning scan, and two doctors given the same scan do not draw the same outline. A 2016 review found 119 studies measuring this across every major cancer site,...Open in Atlas Source
Vascular resection in pancreatic cancer surgery (portal and superior mesenteric vein resection; arterial resection): When a pancreatic cancer touches or narrows the big vein behind the pancreas, surgeons can cut out that segment of vein and rebuild it during the operation, which turns a borderline tumour into a removable one. Removing and rebuilding an artery is far riski...Open in Atlas Source
Vein-to-vein time and manufacturing slots: For CAR-T, the number of days from collecting the patient's cells to infusing the finished product, typically three to six weeks. Every day counts when the disease is aggressive, and manufacturing capacity (slots) limits how many patients can be treated.Open in Atlas Source
Venous thromboembolism (VTE): Blood clots in the leg veins or lungs. Cancer makes blood clot more easily and some treatments (IMiDs, anti-VEGF drugs, hormone therapy, central lines, surgery) add risk; clots are the second commonest cause of death in cancer patients after the cancer itself.Open in Atlas Source
Virtual cell models and in-silico perturbation screens: A virtual cell is a computer model of a cell that predicts what happens when a gene is knocked out or a drug is added, letting researchers run perturbation experiments in software before the laboratory.Open in Atlas Source
Von Hippel-Lindau disease: Von Hippel-Lindau disease is an inherited condition causing kidney cancers, adrenal tumours, and blood-vessel tumours of the brain, spine, eye and pancreas from early adulthood. It taught us how cells sense oxygen and gave rise to the drug belzutifan, the f...Open in Atlas Source
VRd and Dara-VRd (myeloma induction regimens): The alphabet soup of myeloma treatment: V (bortezomib, Velcade), R (lenalidomide, Revlimid), d (dexamethasone), Dara (daratumumab), Isa (isatuximab), K (carfilzomib). Dara-VRd, a four-drug quadruplet, is now the standard first treatment for most patients.Open in Atlas Source

W

Warburg effect: Cancer cells burn glucose into lactate even when oxygen is plentiful, an inefficient but fast way to make building blocks. Otto Warburg described it in the 1920s.Open in Atlas Source
Warburg-effect diet claims ('sugar feeds cancer'): Cancer cells take up far more glucose than normal tissue (the Warburg effect, the basis of FDG-PET scans), which leads people to conclude that cutting sugar starves tumours. The biology is real but the conclusion is not: blood glucose is tightly regulated,...Open in Atlas Source
Watch and wait after chemoradiotherapy for rectal cancer: In some people the rectal tumour disappears completely after chemotherapy and radiotherapy. Watch and wait means keeping the rectum and checking it closely instead of removing it, and operating only if the tumour comes back. About a quarter of regrowths hap...Open in Atlas Source
Watch and wait in follicular lymphoma: being told you have cancer and that nobody will treat it: For a slow-growing lymphoma that is not causing problems, treating straight away has not been shown to help people live longer, so the usual plan is regular checks and treatment later. It is the hardest thing in lymphoma to be told, and the evidence behind...Open in Atlas Source
Watch and wait in lymphoma: when the right treatment is none yet: For slow-growing lymphomas that are not causing symptoms, treating straight away does not help people live longer. The usual plan is regular checks and blood tests, and treatment when the disease starts to cause trouble.Open in Atlas Source
Watchful waiting, and how it differs from active surveillance: Two things that sound the same and are not. Active surveillance monitors a cancer closely so it can still be cured if it grows. Watchful waiting gives up the attempt at cure from the start and treats symptoms if and when they appear.Open in Atlas Source
Weight loss, fat digestion and enzymes with gallbladder cancer: Many people with gallbladder cancer lose appetite and weight; small frequent meals, prescribed nutritional drinks, a dietitian, and enzyme capsules if fat is not being digested are the standard NHS-side answers.Open in Atlas Source
What androgen deprivation costs: the side of hormone therapy the survival curves do not show: Hormone therapy for prostate cancer works by removing testosterone, which means hot flushes, loss of sexual desire and erections, tiredness, loss of muscle, weaker bones and a changed body. Trials measure it, and it is the reason the duration question matte...Open in Atlas Source
What follows what in castration-resistant prostate cancer: Once prostate cancer stops responding to standard hormone therapy there are six or seven things left to try, and the order matters. The one rule proved by a trial is that swapping one hormone tablet for another, after the first stopped working quickly, is a...Open in Atlas Source
What is not a second cancer: recurrence, metastasis and field cancerisation: Four different things get called the same thing in conversation and in the news, and the difference changes what the news means. A second cancer is a new disease with its own stage and its own chance of cure. A recurrence is the first one back. A metastasis...Open in Atlas Source
What it costs to aim at a lineage antigen: Almost every lymphoma drug that finds the cancer by a surface marker finds healthy cells carrying the same marker. The side effects are not accidents; they are the treatment working on the wrong cells, and they are predictable from the marker.Open in Atlas Source
What makes a skin cancer high risk: the UK feature lists: Low risk and high risk are the words that actually decide what happens to a keratinocyte cancer in Britain, more than any stage. One high-risk feature is enough. The lists are short, they are about the tumour and the margin, and a clinician can add clinical...Open in Atlas Source
What the NHS in England funds for lymphoma, appraisal by appraisal: A drug licensed for lymphoma is not automatically available on the NHS: NICE appraises each use separately and can recommend it, fund it for a while through the Cancer Drugs Fund, or refuse it. This entry lists what NICE decided for each lymphoma treatment,...Open in Atlas Source
When to seek urgent help with bowel cancer (NHS 111 and 999): Call 999 for signs of sepsis, non-stop bleeding from the bottom or large blood clots, or sudden severe tummy pain with green vomit. Ring the hospital's 24-hour line at once for a temperature outside your team's range, shivering, diarrhoea that has not settl...Open in Atlas Source
When to seek urgent help with gallbladder cancer (NHS 111 and 999): Call 999 for signs of sepsis or heavy bleeding; ring the hospital's 24-hour line or NHS 111 the same day for a temperature or shivering with a stent, for new or returning jaundice, for pain the painkillers do not control, or for being sick for more than two...Open in Atlas Source
When to seek urgent help with pancreatic cancer (NHS 111 and 999): Call 999 for signs of sepsis, vomiting blood with feeling faint, or a swollen painful leg with breathlessness or chest pain. Ring the hospital's 24-hour line at once for a temperature over 37.5 C or below 36 C, shivering with a stent or jaundice, vomiting l...Open in Atlas Source
When to seek urgent help with triple-negative breast cancer (NHS 111 and 999): Call 999 for signs of sepsis, sudden severe breathlessness, a seizure or new confusion; ring the hospital's 24-hour line straight away for a temperature over 37.5 C or below 36 C, for diarrhoea that meets your drug's threshold, for a new cough or breathless...Open in Atlas Source
Which staging edition a breast report uses: UICC TNM 8, TNM 9 and the AJCC prognostic stage: UK breast reports stage against the UICC's 8th edition, and the dataset warns against using the American AJCC 8th instead, because the two differ. The 9th edition, in force from January 2026, leaves breast staging alone; the one thing it changes is how a tu...Open in Atlas Source
Whipple procedure (pancreaticoduodenectomy): The big operation for cancers of the head of the pancreas: the surgeon removes the pancreatic head, the duodenum, the gallbladder and part of the bile duct, then reconnects everything.Open in Atlas Source
WHO Essential Medicines List for cancer: The World Health Organization's list of medicines every health system should provide, which now includes about 60 cancer drugs from cyclophosphamide and cisplatin to trastuzumab, imatinib and PD-1 inhibitors, guiding procurement and pricing in lower-income...Open in Atlas Source
Who is eligible for a PARP inhibitor in prostate cancer, and why the gene matters: PARP inhibitors work in prostate cancer only for men whose tumour carries a fault in a DNA repair gene, and mostly only if that gene is BRCA1 or BRCA2. A fault in ATM, which is often reported on the same panel, does not seem to count.Open in Atlas Source
Whole-brain radiotherapy (WBRT): Irradiating the entire brain, typically 30 Gy in 10 sessions, when metastases are too numerous or too widespread (leptomeningeal) for focused radiosurgery. It controls disease but dulls memory, so it is now reserved for those cases, with hippocampal-avoidan...Open in Atlas Source
Whole-genome doubling (WGD): Whole-genome doubling is a single event in which a cancer cell duplicates its entire genome, becoming tetraploid. It happens in about a third of cancers and buffers the chaos that follows.Open in Atlas Source
Whole-mount pathology: Slicing the whole removed prostate into complete cross-sections on oversized slides, so each slide shows the entire gland in one piece rather than in fragments. It is the reference standard used to check how well a scan found what was really there.Open in Atlas Source
Why nobody knows how many skin cancers there are: the counting rule behind every figure: Cancer registries were never built to count a cancer that people get several of. Britain's registries long recorded only the first basal cell carcinoma and the first squamous cell carcinoma in a person's lifetime, and the headline 'cancer in the UK' figure...Open in Atlas Source
Why people stop taking hedgehog inhibitors: The pills that shrink advanced basal cell carcinoma cause muscle cramps, loss of taste, hair loss and weight loss in almost everyone who takes them. None of that is dangerous, and most people stop anyway, because the drug has to be taken for years and it ta...Open in Atlas Source
Why trials fail: underpowered, wrong endpoint, control arm drift, subgroup fishing, crossover: Trials fail for a short list of reasons that recur: too few patients for the real effect, an endpoint that does not track what matters, a control arm that did better than the planners assumed, a benefit that was only ever a subgroup illusion, and control pa...Open in Atlas Source
Wide local excision: Cutting out a tumour together with a measured rim of normal-looking tissue around it, so that microscopic spread at the edge is removed too.Open in Atlas Source
Wild-type (WT): The normal, unmutated version of a gene. Saying a tumour is 'RAS wild-type' means its RAS gene is not mutated, which for colorectal cancer means EGFR antibodies can work.Open in Atlas Source
Wilms tumour risk markers (anaplasia, 1p/16q loss, 1q gain, SIOP and COG risk groups): Wilms tumour is cured in nine of ten children, so its markers exist to decide who needs less treatment and who needs more: anaplastic cells under the microscope, loss of chromosome pieces 1p and 16q or gain of 1q in the tumour DNA, and, in Europe, how much...Open in Atlas Source
Window-of-opportunity trial: Giving a new drug for a few weeks in the gap between diagnosis and scheduled surgery, then examining the removed tumour to see what the drug did to it. Patients lose nothing (surgery proceeds as planned) and researchers get a direct look at the drug's biolo...Open in Atlas Source
Work and money during breast cancer treatment (UK): Cancer counts as a disability under the Equality Act, so once your employer knows they must consider reasonable adjustments; there is no legal right to paid time off for appointments unless your contract gives one, Statutory Sick Pay applies where there is...Open in Atlas Source
Work and money with bowel cancer (UK): From diagnosis you are protected from discrimination at work by the Equality Act 2010, and your employer must consider reasonable adjustments such as different hours, time off for appointments, changed duties or a phased return. Access to Work can fund equi...Open in Atlas Source
Work and money with pancreatic cancer (UK): Cancer counts as a disability, so your employer must consider reasonable adjustments; benefits such as PIP, Attendance Allowance and Carer's Allowance may apply, an SR1 form from your doctor speeds claims where the cancer cannot be cured, prescriptions are...Open in Atlas Source

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Zenodo DOIs for data and code: Zenodo is CERN's free open repository where researchers deposit datasets, code and papers and receive a permanent DOI for each version, so a result can cite exactly the files it used.Open in Atlas Source
Zero-shot prediction: Zero-shot prediction applies a model to a task or class it was never trained on, with no task-specific labels at all.Open in Atlas Source

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1p/19q codeletion: Loss of one whole arm each of chromosomes 1 and 19, together with an IDH mutation, is what now defines an oligodendroglioma; a codeleted tumour grows slowly and responds to PCV chemotherapy plus radiotherapy for many years, so the test decides both the diag...Open in Atlas Source
21st Century Cures Act: A 2016 US law that funded the Cancer Moonshot, created the RMAT designation for cell and gene therapies, told the FDA to work out how real-world data could support approvals, and made companies publish how patients can request unapproved drugs.Open in Atlas Source
340B Drug Pricing Program: A US law that lets certain hospitals buy outpatient drugs, including cancer drugs, at deep discounts. Controversial because hospitals may bill insurers full price.Open in Atlas Source
7+3 induction chemotherapy: The classic first treatment for acute myeloid leukaemia, unchanged since 1973: seven days of continuous cytarabine plus three days of an anthracycline, given in hospital. Fit patients still get it, now with a targeted drug added according to their leukaemia...Open in Atlas Source