Epirubicin cardiotoxicity: a study of 135 patients with advanced breast cancer. The cardiotoxicity of epirubicin (EPI) was evaluated clinically, radiologically, with ECG, and with multiple ECG-gated radionuclide determination of the left ventricular ejection fraction (LVEF) during rest in 135 patients with advanced breast cancer. The EPI doses were 60 mg/m2 on days 1 and 8 every 4 weeks or 45 mg/m2 plus vindesine 3 mg/m2 on the same schedule. The median cumulative dose of EPI was 500 mg/m2 (range, 47 to 1,563). Eight of the 135 patients developed congestive heart failure (CHF). Of 67 patients treated with EPI less than 500 mg/m2, none developed CHF. Among 48 patients treated with doses between 500 and 1,000 mg/m2, one had CHF (2%; 95% confidence limits, 0.1 to 11.1). Among 20 patients who received EPI from 1,000 to 1,563 mg/m2, seven developed CHF (35%; 95% confidence limits, 15.4 to 59.2). Four patients died due to cardiotoxicity. The risk of EPI cardiotoxicity at the present schedule is considerable at doses above 1,000 mg/m2. At doses between 500 and 1,000 mg/m2 the risk of CHF decreases, and at doses below 500 mg/m2, it is negligible. For all patients, the prevalence of CHF was 6% and the sensitivity of LVEF high (95%), mainly due to the low incidence of CHF. Among the 20 patients who received EPI at more than 1,000 mg/m2, the prevalence of CHF was 35% and the sensitivity only 64%. The specificity was maximally 62%. Our results suggest that LVEF is of no value as a predictor for CHF. 