A 62-year-old woman with breast cancer treated with an anthracycline-containing regimen develops progressive exertional dyspnea. Echocardiography shows a dilated left ventricle with LVEF 35%. Which feature of anthracycline cardiotoxicity is correct?

• A Risk is independent of cumulative dose
• B Myocyte injury is due to free radical generation and mitochondrial damage ✓
• C Cardiomyopathy typically appears within days of the first dose
• D Dexrazoxane increases the risk of cardiomyopathy

Explanation

Anthracyclines generate reactive oxygen species and damage mitochondrial DNA, causing myocyte loss and a dose-dependent dilated cardiomyopathy that may appear years after therapy. The classic cumulative dose threshold is around 450 to 550 mg/m2 of doxorubicin. Dexrazoxane is an iron chelator that reduces, not increases, the risk. Early transient pericarditis-like changes can occur acutely, but the clinically important cardiomyopathy is late onset.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

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Written and medically reviewed by the StethoPrep medical team.