BACKGROUND

Doxorubicin is a highly effective and widely used cytotoxic agent with application that is limited by cardiotoxicity related to the cumulative dose of the drug. A large-scale study that retrospectively evaluated the cardiotoxicity of doxorubicin reported that an estimated 7% of patients developed doxorubicin-related congestive heart failure (CHF) after a cumulative dose of 550 mg/m(2). To assess whether this estimate is reflective of the incidence in the broader clinical oncology setting, the authors evaluated data from three prospective studies to determine both the incidence of doxorubicin-related CHF and the accumulated dose of doxorubicin at which CHF occurs.

METHODS

A group of 630 patients who were randomized to a doxorubicin-plus-placebo arm of three Phase III studies, two studies in patients with breast carcinoma and one study in patients with small cell lung carcinoma, were included in the analysis.

RESULTS

Thirty-two of 630 patients had a diagnosis of CHF. Analysis indicated that an estimated cumulative 26% of patients would experience doxorubicin-related CHF at a cumulative dose of 550 mg/m(2). Age appeared to be an important risk factor for doxorubicin-related CHF after a cumulative dose of 400 mg/m(2), with older patients (age > 65 years) showing a greater incidence of CHF compared with younger patients (age < or = 65 years). In addition, > 50% of the patients who experienced doxorubicin-related CHF had a reduction < 30% in left ventricular ejection fraction (LVEF) while they were on study.

CONCLUSIONS

Doxorubicin-related CHF occurs with greater frequency and at a lower cumulative dose than previously reported. These findings further indicate that LVEF is not an accurate predictor of CHF in patients who receive doxorubicin.