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QTc Management Systematic — SCE Medical Oncology MCQ

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ModerateLung CancerQTc Management SystematicSCE Medical Oncology

A 58-year-old woman with NSCLC on osimertinib is found to have a prolonged QTc on routine ECG (495 ms). She is on concomitant ondansetron. What is the management of QTc prolongation in this context?

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Correct answer: C — Review and stop concomitant QTc-prolonging medications (ondansetron), correct electrolytes (K+, Mg2+, Ca2+) and repeat ECG — osimertinib dose reduction only if QTc remains prolonged after correcting reversible factors

QTc prolongation management follows a systematic approach: (1) identify and stop concomitant QTc-prolonging drugs (ondansetron, domperidone, haloperidol, macrolides, fluoroquinolones, antifungals), (2) correct electrolyte abnormalities (K+ >4.0, Mg2+ >0.7), (3) repeat ECG after corrections, (4) only if QTc remains >480 ms after corrections, hold/dose-reduce the oncology drug. Many cases of QTc prolongation in cancer patients are multifactorial. Osimertinib dose reduction (80→40 mg) is used if persistent QTc >481 ms.

Reference: BNF Osimertinib; ESMO Supportive Care; NICE TA654