Arab Board Oncology Clinical key terms

A mutated or overexpressed gene that drives uncontrolled cell growth and survival, acting dominantly to promote cancer when one allele is altered. Examples include RAS and MYC.

A gene whose normal function restrains cell division or triggers repair and death of damaged cells. Cancer typically requires loss of both alleles, as with TP53 and RB1.

Loss of the remaining functional allele of a tumor suppressor gene in a cell that already carries one defective copy, removing the last brake on growth.

Knudson's model stating that retinoblastoma and similar cancers arise only after both copies of a tumor suppressor gene are inactivated, explaining earlier onset in inherited disease.

A genetic alteration that directly confers a growth or survival advantage and contributes to cancer development, as opposed to a passenger mutation with no causal role.

A genomic change in a tumor for which a targeted therapy exists or a specific clinical trial can be offered, making molecular testing clinically meaningful.

A framework describing core biological capabilities acquired during tumor development, such as sustained proliferation, evasion of growth suppression, angiogenesis, immune evasion, and metastasis.

Formation of new blood vessels from existing vasculature, driven largely by vascular endothelial growth factor, which supplies oxygen and nutrients to a growing tumor.

Mechanisms by which tumor cells avoid recognition and destruction by the immune system, including downregulation of antigen presentation and recruitment of suppressive cells.

The mixture of cancer cells, fibroblasts, blood vessels, and immune cells surrounding a tumor, whose interactions influence growth, invasion, and response to therapy.

The number of new cancer cases arising in a defined population during a specified period, usually expressed per 100,000 persons per year and adjusted for age structure.

An incidence or mortality rate recalculated against a fixed reference age distribution so that populations with different age structures can be compared fairly.

A rate calculated from total events divided by total population without adjustment for age structure, and therefore strongly influenced by how old a population is.

The total number of people living with a cancer diagnosis at a given time, including those cured or in remission, reflecting both incidence and survival.

A test applied to asymptomatic people to detect cancer or precancer at an earlier, more treatable stage. It must have proven mortality benefit in a population.

Apparent improvement in survival after screening caused only by earlier diagnosis, without any real change in the time of death, which can falsely suggest benefit.

The tendency of screening to detect slow-growing tumors with long preclinical phases disproportionately, making screened patients appear to survive longer regardless of treatment effect.

Sensitivity is the proportion of people with disease correctly identified as positive; specificity is the proportion without disease correctly identified as negative.

The probability that a person with a positive test result actually has the disease, which depends strongly on disease prevalence in the tested population.

A system classifying malignant tumors by extent of the primary tumor (T), regional lymph node involvement (N), and distant metastasis (M) to guide treatment and prognosis.

Staging determined from examination of surgically resected tissue, including tumor size, invasion depth, and node histology, and generally more accurate than clinical staging.

Staging based on information available before definitive surgery, such as examination, imaging, and biopsy results, used to plan initial treatment strategy.

Microscopic assessment of how closely tumor cells resemble their normal counterparts, reflecting differentiation and aggressiveness, and usually reported separately from stage.

Diagnosis of disease by microscopic examination of stained tissue sections, defining tumor type, grade, margins, and other features essential for treatment planning.

A technique using labeled antibodies to detect specific proteins in tissue sections, such as hormone receptors or lineage markers, to refine diagnosis and guide therapy.

A measurable tumor or patient characteristic that predicts the likelihood of benefit from a specific treatment, such as HER2 amplification predicting response to trastuzumab.

Use of cytotoxic drugs that interfere with DNA replication or cell division to kill rapidly dividing cells, typically affecting both tumor and normal proliferating tissues.

Drugs designed to inhibit specific molecules or pathways on which a tumor depends, such as mutated kinases or overexpressed receptors, usually with less broad toxicity.

An antibody that blocks inhibitory immune receptors such as PD-1, PD-L1, or CTLA-4, restoring T-cell activity against tumor cells and producing durable responses in some cancers.

A laboratory-produced antibody binding a single specific target, used to block growth signals, deliver cytotoxic payloads, or engage immune cells against tumor antigens.

A monoclonal antibody linked to a cytotoxic drug that delivers chemotherapy selectively to cells expressing the antibody's target antigen, widening the therapeutic index.

Treatment given after apparently complete removal of a tumor to eliminate microscopic residual disease and reduce the risk of recurrence and death.

Treatment given before definitive local therapy, aiming to shrink the tumor, enable less extensive surgery, and provide information about treatment sensitivity.

Absence of residual invasive tumor in the resected specimen after neoadjuvant treatment, a favorable prognostic finding increasingly used as a trial endpoint.

The lowest blood cell count reached after cytotoxic chemotherapy, typically 7 to 14 days after administration, marking the period of greatest infection and bleeding risk.

Fever with an absolute neutrophil count below 500 per microliter, a medical emergency requiring prompt empiric broad-spectrum antibiotics and often growth factor support.

Rapid destruction of many tumor cells releasing potassium, phosphate, and nucleic acids, causing hyperkalemia, hyperphosphatemia, hypocalcemia, hyperuricemia, and acute kidney injury.

A cancer-related condition requiring immediate intervention to prevent death or permanent disability, such as spinal cord compression, superior vena cava obstruction, or febrile neutropenia.

Pressure on the spinal cord by epidural tumor causing back pain, weakness, sensory loss, and sphincter dysfunction; requires urgent corticosteroids and radiotherapy or surgery.

Division of a prescribed radiation dose into multiple smaller daily treatments, allowing normal tissue repair between fractions while achieving greater tumor cell kill.

Radiation given with the goal of relieving symptoms such as pain, bleeding, or obstruction rather than curing disease, usually in short courses.

An agent given with radiation to increase tumor cell killing, for example concurrent chemotherapy that inhibits DNA repair and improves local control.

Concurrent delivery of chemotherapy and radiotherapy, used as definitive treatment for several cancers such as locally advanced cervical and head and neck carcinoma.

Interdisciplinary care focused on relieving physical, psychological, social, and spiritual suffering and improving quality of life for patients with serious illness and their families.

An ongoing process in which patients discuss and document their values and preferences for future medical care, including resuscitation and use of life-sustaining treatments.

A study assigning participants randomly to intervention or control groups to balance known and unknown confounders, providing the strongest evidence for causal treatment effects.

Analysis of trial results according to the group originally assigned, regardless of adherence, preserving the benefits of randomization and avoiding bias from selective dropout.

Analysis restricted to participants who completed treatment as specified, which may reflect ideal efficacy but risks bias because patients who deviate are often different.

A measure comparing the instantaneous risk of an event between two groups over time, used in time-to-event analyses such as overall and progression-free survival.

A graphical estimate of the probability of survival over time that accounts for patients censored before an event occurs, commonly used in oncology trials.

Statistical methods analyzing time until an event such as death or progression, accommodating censored observations and comparing survival distributions between groups.

A range of values likely to contain the true population estimate with a stated probability, conveying both the size and the precision of an observed effect.

The number of patients who must receive an intervention for one additional patient to benefit, calculated as the reciprocal of the absolute risk reduction.