A 48-year-old woman with HER2-positive breast cancer is treated with trastuzumab (Herceptin). She develops dyspnea and ejection fraction drops from 65% to 40%. This cardiotoxicity differs from anthracycline cardiotoxicity in that it is:

• A Dose-dependent and causes permanent structural cardiac damage
• B Dose-independent and generally reversible on discontinuation ✓
• C Mediated by iron-free radical mechanism similar to doxorubicin
• D Due to myocardial fibrosis seen on biopsy

Explanation

Trastuzumab-related cardiotoxicity (type II cardiotoxicity) is typically dose-independent, not associated with cumulative dose, and is generally reversible upon drug discontinuation — unlike anthracycline (type I) cardiotoxicity, which is cumulative, dose-dependent, and causes irreversible ultrastructural myocardial damage. Trastuzumab cardiotoxicity results from blocking HER2 signaling which is normally cardioprotective; there is no direct toxic damage to cardiac mitochondria.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.