CSP Clinical Management: Oncology 2 — Questions and Answers
Question 1: A patient stable on imatinib for CML is started on rifampin for tuberculosis. What is the expected effect on imatinib?
- Increased imatinib levels and toxicity
- Decreased imatinib exposure and possible loss of response (Correct answer)
- No clinically relevant interaction
- Increased risk of QT prolongation only
Correct answer: Decreased imatinib exposure and possible loss of response
Rifampin strongly induces CYP3A4, which metabolizes imatinib, lowering its plasma concentrations.
Question 2: Which pharmacogenomic test identifies patients at increased risk of severe or fatal toxicity from capecitabine?
- TPMT genotyping
- UGT1A1 genotyping
- DPYD genotyping (Correct answer)
- CYP2D6 genotyping
Correct answer: DPYD genotyping
DPYD variants reduce dihydropyrimidine dehydrogenase activity, impairing fluoropyrimidine clearance and causing severe toxicity.
Question 3: Why is abiraterone acetate co-administered with prednisone in metastatic prostate cancer?
- To reduce mineralocorticoid excess such as hypokalemia, hypertension, and fluid retention (Correct answer)
- To enhance androgen receptor blockade
- To prevent tumor flare at initiation
- To increase oral absorption of abiraterone
Correct answer: To reduce mineralocorticoid excess such as hypokalemia, hypertension, and fluid retention
CYP17 inhibition raises ACTH and mineralocorticoid levels, and prednisone suppresses this compensatory effect.
Question 4: Which adverse effect of ibrutinib warrants periodic cardiac monitoring and patient counseling?
- Bradycardia from AV block only
- Atrial fibrillation (Correct answer)
- Dilated cardiomyopathy from anthracycline-like toxicity
- Pericardial effusion
Correct answer: Atrial fibrillation
Ibrutinib is associated with atrial fibrillation and bleeding, so palpitations should be reported and anticoagulant use carefully assessed.
Question 5: Osimertinib is preferred in EGFR-mutated NSCLC partly because it is active against which resistance mutation?
- ALK rearrangement
- KRAS G12C
- EGFR T790M (Correct answer)
- BRAF V600E
Correct answer: EGFR T790M
Osimertinib is a third-generation EGFR TKI that inhibits both sensitizing EGFR mutations and the T790M resistance mutation.
Question 6: A multiple myeloma patient begins lenalidomide plus dexamethasone. Which supportive measure is recommended?
- Routine G-CSF prophylaxis
- Daily allopurinol for 1 year
- Venous thromboembolism prophylaxis such as aspirin or LMWH based on risk (Correct answer)
- Prophylactic magnesium supplementation
Correct answer: Venous thromboembolism prophylaxis such as aspirin or LMWH based on risk
Immunomodulatory drugs combined with dexamethasone significantly increase VTE risk, requiring risk-based thromboprophylaxis.
Question 7: Olaparib is most appropriately used in which patient population?
- HER2-positive breast cancer
- BRCA-mutated ovarian, breast, prostate, or pancreatic cancer (Correct answer)
- EGFR-mutated lung cancer
- Philadelphia chromosome-positive ALL
Correct answer: BRCA-mutated ovarian, breast, prostate, or pancreatic cancer
PARP inhibitors exploit synthetic lethality in tumors with homologous recombination deficiency such as BRCA mutations.
