Reduced cardiotoxicity of doxorubicin by a 6-hour infusion regimen. A prospective randomized evaluation.

In order to evaluate the possible cardiosparing effect of a prolonged infusion of doxorubicin as compared with the standard mode of administration 62 consecutive patients with metastatic carcinoma of the breast or carcinoma of the ovary Stage III or IV were prospectively randomized to receive doxorubicin either as a rapid infusion over 15 to 20 minutes at 8 AM or as a continuous infusion over 6 hours, 8 AM to 2 PM. The remaining protocol was identical for the two groups. The cardiotoxic effect of doxorubicin was evaluated by history and physical examination and by the decline in resting ventricular ejection fraction (LVEF) as determined by gated pool radionuclide angiography with technetium 99m (99mTc) and by the decline in the height of the QRS complexes in the standard leads of the echocardiogram (ECG). Initially there were 31 patients in each group. The cumulative dose of doxorubicin, was 410 mg/m2 +/- 42 SD in the standard infusion group and 428 mg/m2 +/- 48 SD in the 6-hour infusion group. The mean decline in LVEF after a cumulative doxorubicin dose of 300 mg/m2 was 17% in the first group and only 4.1% in the second. After 400 mg/m2 the mean fall in LVEF was 21% in the first group and 6% in the second. The mean decline in QRS voltage after 300 mg/m2 was 29% and 1.5%, respectively. Four patients, all in the standard infusion group, developed congestive heart failure. These data suggest that slow infusion of doxorubicin is associated with reduced cardiotoxicity.