Heart Failure Induced by Darolutamide in an Older Patient With M0 Castration‐Resistant Prostate Cancer: A Case Report

Introduction: Androgen receptor signaling inhibitors (ARSIs) improve survival in prostate cancer; however, it may increase cardiovascular risks, especially in elderly patients with heart disease. Case Presentation: A 94-year-old man with aortic valve stenosis, hypertension, and diabetes had a nodal metastatic progression of prostate cancer at 88 years of age, leading to the implementation of androgen deprivation therapy (ADT). After 5 years of therapy, prostate-specific antigen (PSA) re-elevated; however, ADT was maintained. At 94 years old, darolutamide was started due to worsening of urinary symptoms. Although these symptoms improved, the patient developed a heart failure with elevated B-type natriuretic peptide (BNP). Darolutamide was discontinued, leading to reduced BNP levels but increased PSA levels. A reduced dose (300 mg/day) resulted in stable PSA levels without BNP elevation. Conclusion: Careful cardiovascular monitoring is crucial when ARSIs are used in older patients with heart disease. Dose adjustments may help balance oncological benefits and cardiac safety.