UKMLA PLAB AMC USMLE Prometric MCQ

Question:
Secondary malignancy is a known side effect of several cytotoxic drugs. Which of the following cytotoxic drugs is most likely to lead to the acute nonlymphoblastic leukaemia (ANLL) ?

a) melphalan
b) 5-fluorouracil
c) taxoids
d) cyclopentenyl cytosine
e) trastuzumab

Correct Answer: A

Explanation:

All alkylating agents (particularly melphalan) have been associated with both myelodysplastic syndrome (MDS) and acute nonlymphoblastic leukaemia (ANLL). MDS is usually characterised by cytopenias and occurs before acute leukaemia develops. The median time from starting chemotherapy to overt leukaemia is 3-4 years. Cytogenetic abnormalities occur in 90% (especially chromosomes 5 and 7). Therapy for ANLL is usually unsuccessful.