Early and delayed clinical cardiotoxicity of doxorubicin

Five hundred thirty‐four evaluable patients with breast cancer were treated with a combination of 5‐fluorouracil, doxorubicin, and cyclophosphamide. The total planned dose of doxorubicin was 300 mg/m² in patients with Stage II or III disease, and 450 mg/m² in patients with isolated recurrences. The median time interval from start of adjuvant therapy to time of analysis was 68 months. Two percent had congestive heart failure associated with doxorubicin. Fifteen patients showed myocardial dysfunction attributed to either additional treatment with potentially cardiotoxic drugs for recurrent disease or other causes. The incidence of congestive heart failure was 1% in patients treated with up to 300 mg/m², and 4% in patients who received 450 mg/m² of doxorubicin. The median time interval from the end of doxorubicin to development of congestive heart failure was 1 month (range, 0–33 months). None of the 326 patients who have been followed 3 or more years (162 followed 5 or more years) since completion of doxorubicin therapy have developed congestive heart failure which was considered to be related from that therapy.