Arab Board Oncology Clinical flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Two-hit hypothesis

Tumor suppressor genes typically require inactivation of both alleles to promote cancer, as described by Knudson for retinoblastoma; heterozygous carriers inherit one hit and acquire the second somatically.

Synthetic lethality

Two gene defects are lethal only when combined; BRCA-mutant cells depend on PARP for repair, so PARP inhibition selectively kills them while sparing normal cells.

Warburg effect

Tumor cells preferentially use aerobic glycolysis even with oxygen present, producing lactate; this underlies FDG-PET imaging and informs metabolic targeting strategies.

Lead-time bias

Screening advances diagnosis without changing the time of death, artificially lengthening measured survival; mortality endpoints avoid this bias in screening trials.

Length-time bias

Screening preferentially detects slow-growing tumors with long preclinical phases, exaggerating apparent survival benefit; randomized mortality trials control for this.

Positive predictive value

Proportion of test-positives who truly have disease; unlike sensitivity and specificity, PPV rises with disease prevalence in the screened population.

Lynch syndrome

Hereditary mismatch repair deficiency caused by germline MMR gene mutations; confers high colorectal and endometrial cancer risk and predicts immunotherapy response in MSI-H tumors.

TNM staging

Anatomic classification of tumor extent (T), regional nodal involvement (N), and distant metastasis (M); stage grouping guides prognosis and treatment selection.

Sentinel lymph node biopsy

Identification and removal of the first draining node using dye or radiolabeled colloid; if negative, complete regional lymphadenectomy is usually unnecessary in breast cancer and melanoma.

RECIST 1.1 progression

Progression requires at least a 20% increase in the sum of target lesion diameters from nadir, with an absolute increase of at least 5 mm, or new lesions.

DPYD deficiency

Reduced dihydropyrimidine dehydrogenase activity causes severe or fatal toxicity with fluoropyrimidines; genotype-guided dose reduction is recommended before 5-FU or capecitabine.

Immune-related adverse events

Autoimmune toxicities from checkpoint inhibitors such as colitis, pneumonitis, thyroiditis, and hypophysitis; managed with corticosteroids and drug interruption or discontinuation by grade.

Antibody-drug conjugate

A monoclonal antibody linked to a cytotoxic payload that delivers chemotherapy selectively to antigen-expressing tumor cells; examples include T-DM1 and trastuzumab deruxtecan.

Linear-quadratic model

Radiation survival model where surviving fraction equals exp(-(alpha*d + beta*d^2)); the alpha/beta ratio predicts fractionation sensitivity of tumors versus late normal tissues.

Biologically effective dose

BED equals total dose times (1 + dose per fraction divided by alpha/beta); it allows comparison of different fractionation schemes in radiotherapy.

Spinal cord tolerance

Conventional fractionated radiotherapy limits spinal cord dose to approximately 45-50 Gy; higher cumulative doses risk radiation myelopathy, a late irreversible toxicity.

R0 resection

Surgical removal with microscopically negative margins; R1 indicates microscopic residual disease and R2 macroscopic residual, both associated with worse local control and survival.

Neoadjuvant chemotherapy

Systemic therapy given before surgery to shrink tumors, test in vivo response, and increase organ-preserving resection rates; pathologic complete response is a favorable prognostic marker.

HIPEC

Heated intraperitoneal chemotherapy delivered after cytoreductive surgery for selected peritoneal carcinomatosis, notably colorectal and appendiceal primaries.

Trastuzumab deruxtecan

A HER2-directed antibody-drug conjugate with a topoisomerase I payload; active in HER2-positive and HER2-low breast cancer and in gastric cancer.

MGMT promoter methylation

Epigenetic silencing of the DNA repair gene MGMT in glioblastoma; predicts benefit from temozolomide and is a favorable prognostic marker.

MSI-H colorectal cancer

Mismatch repair-deficient tumors with high microsatellite instability; they respond well to immune checkpoint inhibitors and have distinct prognosis.

APL coagulopathy

Acute promyelocytic leukemia frequently presents with disseminated intravascular coagulation; early ATRA initiation before confirmation reduces early hemorrhagic mortality.

CML Philadelphia chromosome

Reciprocal translocation t(9;22) creating BCR-ABL1 tyrosine kinase; targeted with imatinib or other TKIs, with deep molecular response permitting treatment discontinuation.

Multiple myeloma CRAB criteria

Diagnostic features: hyperCalcemia, Renal insufficiency, Anemia, and Bone lesions; plus SLiM biomarkers of malignancy such as involved/uninvolved free light chain ratio >=100.

Febrile neutropenia

Fever >=38.3 C once or >=38.0 C sustained with absolute neutrophil count below 500; requires empiric anti-pseudomonal beta-lactam therapy within 60 minutes.

Tumor lysis syndrome

Metabolic emergency with hyperkalemia, hyperphosphatemia, hyperuricemia, and hypocalcemia from rapid tumor breakdown; prevented with hydration, allopurinol, or rasburicase.

Malignant spinal cord compression

Back pain with progressive neurologic deficit from epidural tumor; requires immediate dexamethasone, urgent MRI, and definitive surgery or radiotherapy to preserve function.

Hypercalcemia of malignancy

Elevated calcium from tumor PTHrP secretion or bone destruction; managed with intravenous fluids, bisphosphonates or denosumab, and calcitonin for rapid control.

Intention-to-treat analysis

Analyzes all randomized participants according to assigned group regardless of adherence; preserves randomization and avoids bias from selective dropout.

Number needed to treat

Reciprocal of the absolute risk reduction; it estimates how many patients must be treated to prevent one additional adverse outcome.

Phase I trial endpoint

Primarily determines safety, maximum tolerated dose, and dose-limiting toxicity; efficacy is exploratory and response rates are typically low.