IM13.1-19 | Common Malignancies and Oncology — Glossary

The four biological processes that determine the therapeutic ratio of fractionated radiotherapy: Repair (normal tissue repairs between fractions better than tumour), Redistribution (cells move into sensitive cell-cycle phases), Repopulation (normal tissue repopulates faster), Reoxygenation (hypoxic, radiation-resistant tumour cells are reoxygenated between fractions); collectively, they explain why fractionation improves tumour killing while sparing normal tissue.

A velvety, hyperpigmented thickening of the skin in the axilla, neck, and groin, classically associated with insulin resistance (obesity, type 2 diabetes); when occurring acutely in a non-obese adult, it is a paraneoplastic marker most strongly associated with gastric adenocarcinoma (and other GI cancers).

The Breast Imaging Reporting and Data System of the American College of Radiology, a standardised 0–6 scale for reporting mammography findings: 0 = incomplete; 1 = negative; 2 = benign; 3 = probably benign (<2% malignancy, 6-month follow-up); 4 = suspicious (biopsy); 5 = highly malignant (biopsy); 6 = known malignancy.

Systemic or radiation therapy administered after curative resection to reduce the risk of relapse from residual microscopic disease; examples: adjuvant trastuzumab for HER2-positive breast cancer, adjuvant FOLFOX for Stage III colorectal cancer, adjuvant cisplatin for resected NSCLC.

A legal document in which a person with decision-making capacity records their preferences about future medical treatment — specifically, refusal of extraordinary life-sustaining measures if they become incapacitated and terminally ill; legally valid in India since Common Cause v. Union of India (2018), requiring countersignature by a gazetted magistrate or officer.

Cytotoxic chemotherapy agents that form covalent bonds with DNA bases, causing cross-links and strand breaks; cell-cycle non-specific; examples: cyclophosphamide, cisplatin, carboplatin, oxaliplatin; key toxicities: nephrotoxicity (cisplatin), myelosuppression, peripheral neuropathy (oxaliplatin).

A glycoprotein normally produced by the foetal yolk sac and liver; elevated in hepatocellular carcinoma (>400 ng/mL in the context of cirrhosis and typical radiological features allows diagnosis without biopsy) and non-seminomatous germ cell tumours; the only tumour marker endorsed for cancer surveillance (HCC in cirrhosis).

Cytotoxic antibiotics (doxorubicin, epirubicin, daunorubicin) that intercalate DNA and inhibit topoisomerase II; active against many solid and haematological malignancies; key toxicity: cumulative dose-dependent cardiomyopathy (doxorubicin lifetime dose limit ~450 mg/m²); also cause alopecia and myelosuppression.

Needle-shaped azurophilic crystalline inclusions in the cytoplasm of myeloblasts, formed from fused primary lysosomes; pathognomonic of acute myeloid leukaemia (AML); their presence differentiates AML from ALL (where Auer rods are absent) and from other causes of circulating blasts.

Constitutional symptoms used in lymphoma staging (Ann Arbor system): fever >38°C (unexplained), drenching night sweats, and unintentional weight loss >10% body weight over 6 months; their presence designates 'B' status (e.g., Stage IIIB) and confers a worse prognosis.

Tumour suppressor genes involved in homologous recombination repair of DNA double-strand breaks; germline pathogenic variants confer lifetime breast cancer risk of 60–80% and ovarian cancer risk of 15–40% (BRCA1); important for targeted treatment with PARP inhibitors (olaparib).

A transient, severe exacerbation of pain occurring on a background of otherwise controlled persistent cancer pain; may be incident (triggered by movement or activity) or spontaneous; managed with a short-acting opioid rescue dose (10–15% of total daily opioid dose) available on demand in addition to regular around-the-clock opioids.

The depth of melanoma invasion in millimetres, measured histologically from the granular layer of the epidermis to the deepest invasive tumour cell; the single most important prognostic factor for cutaneous melanoma (T1: ≤1 mm; T2: 1–2 mm; T3: 2–4 mm; T4: >4 mm in AJCC 8th edition).

A validated multi-dimensional cancer pain assessment tool that measures intensity (worst, least, average, current pain — each 0–10) and interference with function (walking, work, mood, sleep, relationships — each 0–10); the WHO-recommended comprehensive cancer pain assessment tool; available in validated Hindi translation.

A high-molecular-weight glycoprotein expressed by coelomic epithelium; elevated in >80% of advanced epithelial ovarian cancers; used for monitoring treatment response and detecting recurrence; not specific enough for screening (false positives in endometriosis, PID, cirrhosis, and other conditions); combined with HE4 in the ROMA algorithm for risk stratification.

A complex metabolic syndrome in advanced cancer characterised by involuntary weight loss, muscle wasting, anorexia, and fatigue; driven by cytokine-mediated catabolism (TNF-alpha, IL-6), not nutritional deficiency; does not respond to simple nutritional supplementation; managed with corticosteroids (dexamethasone) or megestrol acetate for short-term appetite stimulation in terminal patients.

A spectrum of pre-invasive squamous dysplasia of the cervical epithelium graded CIN 1 (mild dysplasia), CIN 2 (moderate), and CIN 3 (severe/carcinoma in situ); caused by high-risk HPV infection; detected by Pap smear/HPV DNA testing and treated by LEEP, cryotherapy, or cold knife cone biopsy.

A sampling technique using a larger cutting needle (14–18G) to extract a cylinder of tissue; provides histological diagnosis with preserved architecture, tumour grade, and immunohistochemical markers (ER, PR, HER2, Ki-67, CD markers for lymphoma subtyping); the preferred biopsy method for solid tumours requiring receptor or molecular testing.

The sequence of histological changes in H. pylori-induced gastric carcinogenesis: chronic active gastritis → atrophic gastritis → intestinal metaplasia → dysplasia → gastric adenocarcinoma; represents a multi-decade process allowing potential intervention at pre-malignant stages.

A treatment approach designed to eliminate all malignant disease from the body, aiming for complete and durable remission; accepts higher acute toxicity because the potential long-term benefit of cure justifies it; feasible only when disease is localised, surgically resectable, or highly sensitive to systemic therapy.

A medical order, discussed with the patient and/or family and documented in the medical record, instructing healthcare providers not to initiate CPR in the event of cardiopulmonary arrest; legally and ethically permissible in terminally ill patients in India; does not affect the provision of all other care; also referred to as AND (Allow Natural Death) order.

An ethical principle holding that an action with two possible effects (one intended and good, one foreseen but not intended and potentially harmful) is morally permissible if the action is not intrinsically wrong, the harmful effect is not the means to the good effect, and the benefit is proportionate to the harm; used to justify opioid dosing for cancer pain when a theoretical risk of respiratory depression exists.

A 5-point scale (0–4) from the Eastern Cooperative Oncology Group that grades a cancer patient's functional capacity: PS 0 = fully active; PS 2 = ambulatory but unable to work; PS 3 = confined to bed/chair >50% of waking hours; PS 4 = completely disabled. Strongly predicts chemotherapy tolerance and overall survival.

Activating mutations in the epidermal growth factor receptor gene (most commonly exon 19 deletions and exon 21 L858R point mutations) found in ~30% of East/South Asian lung adenocarcinomas (and ~15% of Western cases); predictive biomarker for response to EGFR tyrosine kinase inhibitors (osimertinib, erlotinib, gefitinib).

The calculation of an equivalent analgesic dose when switching from one opioid to another; based on established conversion ratios (e.g., oral morphine 30 mg ≈ oral oxycodone 20 mg ≈ transdermal fentanyl 12 mcg/h/24h); when rotating, the calculated equianalgesic dose of the new opioid is reduced by 25–30% for incomplete cross-tolerance.

A stool test that detects human haemoglobin protein from the lower gastrointestinal tract using antibodies specific to human Hb; superior to guaiac-based FOBT in specificity (no dietary restrictions); sensitivity ~75–80% for colorectal cancer; a positive result in an asymptomatic screening population mandates colonoscopy.

An autosomal dominant syndrome caused by germline APC mutations; characterised by hundreds to thousands of colorectal adenomatous polyps with near-certain progression to adenocarcinoma by age 40 if untreated; prophylactic colectomy is the standard management.

The financial harm — distress, debt, poverty, or treatment discontinuation — experienced by patients and families as a result of cancer treatment costs; a major barrier to treatment adherence in India where out-of-pocket cancer expenditure is high; must be assessed and addressed in treatment planning.

A minimally invasive sampling technique using a 22–25G needle to aspirate cells from a lesion; provides cytological diagnosis (cell morphology only, no tissue architecture); rapid, inexpensive, and suitable for palpable superficial lesions; does not allow grading or immunohistochemistry for receptor testing.

A Gram-negative curved rod bacterium colonising the gastric mucosa; IARC Group 1 carcinogen for gastric adenocarcinoma (drives Correa cascade: gastritis → atrophy → metaplasia → dysplasia → cancer) and gastric MALT lymphoma (antigen-driven; early stage cured by H. pylori eradication).

Viral proteins encoded by high-risk HPV types (16, 18) that target the two main tumour suppressor pathways: E6 binds p53 and promotes its ubiquitin-mediated degradation; E7 binds and inactivates the RB1 protein, releasing E2F and driving unchecked S-phase entry.

Monoclonal antibodies targeting inhibitory immune receptors to unleash T-cell anti-tumour immunity; anti-PD-1 (pembrolizumab, nivolumab), anti-PD-L1 (atezolizumab, durvalumab), anti-CTLA-4 (ipilimumab); indications include NSCLC, melanoma, MSI-H solid tumours, urothelial cancer; immune-related adverse events include pneumonitis, colitis, hepatitis, and endocrinopathy.

A 100-point scale (0 = dead; 100 = normal) assessing functional status in cancer patients; roughly the inverse of the ECOG scale; a KPS ≤50 (equivalent to ECOG PS 3–4) indicates the patient is disabled and requires significant support; used in palliative care for prognosis estimation.

The sudden onset or rapid increase in the number and size of seborrhoeic keratoses, recognised as a paraneoplastic sign of internal malignancy, particularly gastrointestinal adenocarcinoma; caused by tumour-derived epidermal growth factor.

A peripheral blood film showing circulating nucleated red blood cells, tear-drop poikilocytes, and immature white cells (myelocytes, metamyelocytes), indicating bone marrow infiltration or replacement by malignancy, myelofibrosis, or severe haemolysis.

Biochemical criteria to classify pleural effusions as exudate or transudate: pleural protein/serum protein >0.5, OR pleural LDH/serum LDH >0.6, OR pleural LDH >2/3 upper limit of normal serum LDH — if any one is met, the effusion is an exudate; malignant and parapneumonic effusions are exudates.

The pharmacological model stating that a given chemotherapy dose kills a constant fraction (rather than a constant number) of tumour cells; implies that multiple cycles are required to reduce tumour burden to zero and that stopping early risks relapse from residual microscopic disease below imaging detection threshold.

The somatic loss of the wild-type (functioning) allele at a tumour suppressor gene locus in a cell that already carries a germline or somatic mutation in the other allele, completing tumour suppressor inactivation.

An autosomal dominant cancer predisposition syndrome caused by germline mutations in DNA mismatch repair genes (MLH1, MSH2, MSH6, PMS2), conferring high lifetime risk of colorectal, endometrial, ovarian, and urothelial cancers; tumours show MSI-H.

Mucosa-associated lymphoid tissue lymphoma; a low-grade extranodal B-cell lymphoma typically arising in the stomach in response to chronic H. pylori antigen stimulation; t(11;18)-negative, localised MALT lymphoma may achieve complete remission with H. pylori eradication therapy alone.

Tiny calcium deposits <0.5 mm visible on mammography; benign types include eggshell (cysts), coarse (fibroadenoma), scattered bilateral (fibrocystic); malignant types: clustered pleomorphic, linear/branching (casting) calcifications representing calcified necrotic debris in DCIS ducts.

A mutational phenotype resulting from DNA mismatch repair (MMR) deficiency, characterised by mutations in short tandem repeat sequences (microsatellites); produces a hypermutated tumour with high neoantigen load; predictive of response to immune checkpoint inhibitors (pembrolizumab).

The pharmacologically active analgesic and respiratory-depressant metabolite of morphine, produced by hepatic glucuronidation; renally cleared; accumulates in renal failure causing opioid toxicity even at previously safe doses; the pharmacological rationale for switching to transdermal fentanyl or hydromorphone in significant renal impairment.

A panel of specialists — surgical, medical, and radiation oncologists; radiologists; pathologists; palliative care specialists — who review individual cases collectively and arrive at evidence-based, consensus treatment recommendations; the gold standard for oncological treatment planning in tertiary centres.

The 2014 amendment to the Narcotic Drugs and Psychotropic Substances Act and associated Rule 14B, which simplified opioid prescribing for palliative care in India by allowing registered medical practitioners to prescribe oral morphine for patients with cancer, HIV, and other specified conditions on a simplified single-carbon-paper prescription form.

Systemic or radiation therapy administered before the planned definitive local treatment (surgery); goals include tumour downstaging, improved surgical margins, treatment of micrometastatic disease, and early delivery of effective systemic therapy; examples: neoadjuvant chemoradiation for rectal cancer, neoadjuvant FLOT for gastro-oesophageal cancer.

Pain arising from a lesion or disease of the somatosensory nervous system — in cancer, caused by direct nerve infiltration, cord compression, chemotherapy-induced neuropathy, or post-radiation changes; characterised by burning, shooting, electric-shock-like sensations, allodynia, and hyperalgesia; requires adjuvant analgesics (gabapentin, pregabalin, amitriptyline) in addition to opioids.

A validated, self-reported pain intensity scale from 0 (no pain) to 10 (worst imaginable pain); mild pain 1–3, moderate 4–6, severe 7–10; the standard bedside cancer pain assessment tool; validated in Hindi, Tamil, Bengali, and other major Indian languages.

A mutated or overexpressed proto-oncogene whose product constitutively stimulates cell proliferation; activated by point mutation (RAS), gene amplification (HER2), or chromosomal translocation (BCR-ABL1, MYC).

The switching of one opioid to a different opioid — at an equianalgesic dose with incomplete cross-tolerance reduction — when the current opioid produces intolerable side effects, opioid-induced hyperalgesia, or inadequate analgesia despite escalation; guided by equianalgesic conversion tables and individual patient factors.

Universal, dose-dependent, non-adapting adverse effect of opioid analgesics caused by mu-receptor activation in the enteric nervous system reducing intestinal motility; must be prophylactically treated with stimulant laxatives (senna, lactulose) co-prescribed from day 1 of opioid initiation; does not diminish over time unlike opioid-induced nausea and sedation.

A chronic premalignant condition of the oral mucosa caused by areca nut (betel nut) chewing; characterised by progressive fibrosis limiting mouth opening (trismus); malignant transformation rate to oral squamous cell carcinoma is 7–13% over 10 years.

A unit quantifying lifetime tobacco exposure: number of cigarette packs smoked per day × number of years smoked (1 pack = 20 cigarettes); e.g., 1.5 packs/day × 20 years = 30 pack-years. Dose-dependent risk predictor for tobacco-related cancers.

An eczematoid, erythematous rash of the nipple-areola complex caused by migration of malignant ductal cells (Paget cells) into the epidermis; virtually always associated with underlying ductal carcinoma in situ (DCIS) or invasive cancer; must be distinguished from benign eczema (Paget's is unilateral and persistent).

A specialty of medicine focused on the prevention and relief of suffering — physical, psychological, social, and spiritual — in patients with life-limiting illness and their families; applicable from the time of diagnosis alongside curative treatment; neither hastens nor postpones death; endorsed by WHO, ASCO, ESMO, and IAPC.

A treatment approach designed to control symptoms, maintain or improve quality of life, and extend life without curative expectation; toxicity threshold is constrained by the absence of curative potential; encompasses chemotherapy, radiotherapy, and supportive care — not 'no treatment'.

The deliberate, proportionate reduction of consciousness in a terminally ill patient with intractable, refractory, and intolerable suffering; uses the minimum sedative dose necessary to relieve suffering; ethically distinct from euthanasia (no intent to hasten death); legal under Indian medical ethics guidelines consistent with the doctrine of double effect; agents: midazolam SC, phenobarbitone.

A group of clinical syndromes caused by remote effects of a tumour — immunological (antibody- or T-cell-mediated) or endocrine (ectopic hormone secretion) — not caused by direct tumour invasion or metastasis; examples include SIADH (SCLC), hypercalcaemia (PTHrP secretion), Lambert-Eaton syndrome (voltage-gated calcium channel antibodies).

Targeted agents (olaparib, niraparib, rucaparib) that inhibit poly(ADP-ribose) polymerase, critical for single-strand DNA break repair; induce synthetic lethality in tumours with homologous recombination deficiency, particularly BRCA1/2-mutated cancers; approved for BRCA-mutated ovarian, breast, prostate, and pancreatic cancers.

The withholding or withdrawal of life-sustaining treatment from a terminally ill or permanently incapacious patient, allowing natural death to occur; legal in India since the Common Cause v. Union of India Supreme Court judgment (March 2018); distinct from active euthanasia (administration of a lethal agent — illegal under IPC 300/306) and from palliative sedation.

An immune regulatory pathway in which tumour cells express PD-L1, binding to PD-1 on T-cells to suppress T-cell cytotoxicity; exploited by tumours to evade immune destruction; targeted by immune checkpoint inhibitors (pembrolizumab, nivolumab, atezolizumab) that restore T-cell anti-tumour function.

An orange-peel skin texture over the breast caused by lymphoedema of the dermal lymphatics, typically due to blockage by invasive breast cancer cells or inflammatory breast cancer infiltrating the subdermal lymphatics; a sign of locally advanced disease.

A functional imaging modality combining PET (using 18F-FDG glucose analogue that concentrates in metabolically active tumour cells) with CT for anatomical localisation; superior to CT alone for staging lymphoma, NSCLC, melanoma, and other FDG-avid tumours; detects unsuspected metastases that may alter curative intent.

The reciprocal chromosomal translocation t(9;22)(q34;q11) that creates the BCR-ABL1 fusion gene encoding a constitutively active tyrosine kinase; the hallmark of chronic myeloid leukaemia (CML); targeted by imatinib and newer TKIs.

A normal cellular gene encoding a protein that promotes cell growth and proliferation; when mutated or overexpressed, it becomes an oncogene driving uncontrolled division (e.g., RAS, HER2, MYC).

Serum PSA (ng/mL) divided by prostate volume (cm³) measured on transrectal ultrasound; a PSA density >0.15 ng/mL/cm³ suggests that PSA elevation is more likely to be due to cancer than to benign prostatic hypertrophy, as cancer contributes disproportionately more PSA per unit volume than BPH.

A complete surgical resection with microscopically clear margins — the standard goal of curative surgical oncology. R1 = microscopic positive margin (high local recurrence risk); R2 = macroscopic residual disease (non-curative).

A collaborative process in which the clinician and patient exchange information, deliberate about options, and reach a mutually acceptable treatment decision integrating clinical evidence with the patient's values, preferences, and life circumstances; a standard of care in oncology ethics and patient communication.

A palpable subcutaneous nodule at the umbilicus caused by peritoneal metastatic spread from an intra-abdominal or pelvic malignancy (commonly gastric, colorectal, or ovarian); its presence indicates disseminated peritoneal disease (typically Stage IV).

Disrupted lymphocytes on peripheral blood films, characteristic of CLL — the mature, fragile lymphocytes of CLL smear during blood film preparation, leaving remnants of nuclear material; their presence is virtually pathognomonic of CLL.

A radiological descriptor for a mass with irregular, radiating needle-like projections from its margin; the most specific sign of malignancy on mammography and CT chest; reflects tumour invasion of adjacent stroma and lymphatics.

Compression or thrombosis of the superior vena cava, most often by a right-sided lung cancer or mediastinal lymphoma; presents with facial and neck oedema, arm swelling, dilated chest wall collateral veins, and positional headache; a recognised oncological emergency requiring urgent intervention.

The axillary extension of breast tissue projecting through an opening in the deep fascia into the axilla; must be included in breast palpation examination as carcinoma can arise in this axillary tail, potentially mimicking an axillary lymph node.

The sensation of incomplete rectal emptying or the persistent urge to defecate after defecation, caused by a rectal mass maintaining the rectal distension reflex; a red-flag symptom for rectal cancer, especially in patients over 40 with rectal bleeding.

The persistent, painful urge to defecate without producing stool, caused by a mass in the rectum maintaining the urge reflex; a classic symptom of rectal cancer, rectal polyps, proctitis, or pelvic peritoneal deposits.

The international staging framework for solid tumours: T = primary tumour size and local invasion depth (T1–T4), N = regional lymph node involvement (N0–N3), M = distant metastasis (M0 or M1); combined to assign clinical stages I–IV with prognostic and treatment implications.

The area of the cervix where the squamous epithelium of the ectocervix meets the columnar epithelium of the endocervical canal (the squamo-columnar junction); this zone undergoes squamous metaplasia and is the site of maximal susceptibility to HPV-induced carcinogenesis and CIN development.

The three-component evaluation protocol for breast lumps: clinical examination (E1–5), imaging (mammography/USS, U1–5), and histopathology (core biopsy, B1–5); a benign verdict requires all three components to be concordantly benign; any discordance mandates biopsy.

The existence of genetically distinct clonal subpopulations within a single tumour; the primary mechanism of acquired drug resistance — minor clones carrying resistance mutations survive selective drug pressure and expand; the rationale for multi-agent combination chemotherapy in curative regimens.

Biological substances (usually proteins) produced by tumour cells or by the host in response to the tumour, measurable in blood; examples: AFP (HCC, testicular), β-hCG (choriocarcinoma, testicular), PSA (prostate), CA 125 (ovarian), CEA (colorectal monitoring); most lack sufficient specificity for screening but are useful for monitoring.

A gene whose protein product inhibits cell proliferation, promotes apoptosis, or repairs DNA damage; loss of function (both alleles) by the two-hit mechanism leads to uncontrolled growth (examples: TP53, RB1, BRCA1/2, APC).

The model proposing that both alleles of a tumour suppressor gene must be inactivated for neoplastic transformation; in familial cancers, one hit is inherited in the germline and the second occurs somatically; in sporadic cancers, both hits are somatic.

A firm, non-tender enlarged left supraclavicular lymph node representing metastatic spread from an intra-abdominal or thoracic primary tumour via the thoracic duct; also called Troisier's sign; classically associated with gastric cancer.

A palpable left supraclavicular lymph node caused by metastatic cancer tracking via the thoracic duct from an intra-abdominal (most commonly gastric) primary tumour; Troisier's sign indicates disseminated upper abdominal or thoracic malignancy.

A WHO/ICMR-endorsed cervical cancer screening method in which 3–5% acetic acid is applied to the cervix; acetowhite changes indicate high-grade lesions (precancerous); allows same-visit cryotherapy treatment (screen-and-treat) without laboratory infrastructure; preferred in low-resource Indian settings.

A three-step framework for cancer pain pharmacotherapy: Step 1 (non-opioids: paracetamol, NSAIDs), Step 2 (weak opioids: tramadol, codeine), Step 3 (strong opioids: morphine, oxycodone, fentanyl); adjuvant analgesics added at any step; five prescribing principles: by mouth, by the clock, by the ladder, for the individual, with attention to detail.