Introduction:
Cardiac complications such as non-infectious myocarditis as a result of oncological treatments are rare but can have life-threatening consequences. According to current guidelines, androgen receptor pathway inhibitors (ARPIs) are the treatment of choice for certain patients with prostate cancer. Nevertheless, it is well established that a therapy using ARPIs can increase the risk of cardiovascular disease.
Case Report:
A 76-year-old man with osseous metastatic prostate cancer (cT2a, Gleason score 8) treated with the ARPI darolutamide developed cardiac arrest from hypoxia-related pulseless electrical activity progressing to ventricular fibrillation (VF) and ventricular tachycardia after 263 days of therapy. Echocardiography showed a cardiomyopathy with severe heart failure (EF 17%). Coronary angiography excluded acute coronary occlusion and ardiac MRI revealed severe chemotoxic myocardial inflammation with edema. Due to a concurrent parainfluenza infection, treatment with prednisolone was contraindicated; therefore, myocardial biopsy was not performed. Standard heart failure therapy was initiated. 46 days after the initial presentation, the patient experienced recurrent VF episodes that triggered shocks from his wearable defibrillator (LifeVest) and amiodarone therapy was initiated. A follow-up CMRI demonstrated regression of myocardial edema but thinning of the lateral left ventricular wall with the EF remaining at 17%. Consequently, an ICD was implanted. Because of the suspected chemotoxic cause, oncologic therapy was switched to leuprorelin acetate.
Discussion:
This paper presents a case of fulminant toxic myocarditis leading to life-threatening arrhythmias and severe heart failure. Although ARPIs are linked to higher cardiovascular risk—mainly ischemic events, atrial fibrillation, and hypertension—reports of cardiogenic shock and heart failure are rare. In our case, the patient showed no improvement and required ICD implantation for recurrent ventricular arrhythmias, but early diagnosis enabled timely oncologic therapy adjustment, likely preventing further decline.
Conclusion:
This case underscores the risk of severe cardiotoxicity from darolutamide. While cardiovascular events are more common than chemotoxic myocarditis during ARPI therapy, drug-induced myocarditis should be considered in prostate cancer patients with acute cardiac symptoms. Early cardiac imaging is essential for diagnosis and treatment adjustment.
