Decreased cardiac toxicity of doxorubicin administered by continuous intravenous infusion in combination chemotherapy for metastatic breast carcinoma.

Two hundred and seventy-four consecutive patients with measurable metastatic breast cancer, without prior exposure to cytotoxic agents were treated with tamoxifen, 5-fluorouracil, doxorubicin, and cyclophosphamide (FAC). The initial 133 patients received doxorubicin by bolus IV administration and for the next group of 141 patients doxorubicin was administered via a central venous catheter over a 48-hour (79 patients) or 96-hour (62 patients) continuous infusion schedule. Patients treated with bolus doxorubicin had this agent discontinued usually when 450 mg/m2 were reached; for patients in the infusion group treatment was continued until evidence of progressive disease or clinical or subclinical cardiac dysfunction developed. The complete remission rate was 21% the partial remission rate, 59%. There were no differences in response rate, response duration, or survival duration between groups of patients treated with doxorubicin by bolus, 48-hour or 96-hour infusion FAC. The incidence of moderate and severe nausea and vomiting was lower in the group of patients treated with infusion FAC as compared to bolus FAC (P less than 0.001); however, the incidence of mucositis was higher in the infusion group than in the bolus group (P less than 0.001). Doxorubicin administered by continuous infusion schedules was less cardiotoxic than when administered by bolus, as shown by a greater than 75% decrease in the frequency of clinical congestive heart failure at cumulative dosages greater than or equal to 450 mg/m2 (P = 0.004). Doxorubicin administered as a 48-hour or 96-hour continuous IV infusion is safer, and better tolerated than doxorubicin administered by bolus.