Paclitaxel plus doxorubicin in metastatic breast cancer: preliminary analysis of cardiotoxicity

This ongoing phase II trial was designed to determine the antitumor activity and cardiotoxicity of a combination of doxorubicin (50 mg/m2) and paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) (175 to 225 mg/m2 over 3 hours) as first-line chemotherapy for metastatic breast cancer. Of 76 patients entered so far, 57 who had received at least three courses of chemotherapy are assessable for efficacy and cardiac toxicity. A slight majority (57%) of the patients entered had prior adjuvant chemotherapy, including 33% with anthracycline-containing combinations. An objective response was achieved by 70% of patients, with 18% complete responders. The main noncardiac toxicities were alopecia, neutropenia, mucositis, and peripheral neuropathy. Overall, after a median cumulative doxorubicin dose of 350 mg/m2, the evolution of left ventricular ejection fraction (LVEF) values did not significantly decrease from baseline to the sixth course of therapy. However, LVEF values decreased significantly in eight patients (14%). The LVEF decreased by more than 14% over basal values in three patients, although the final determination was still above the lower limits of normal. The remaining five patients had LVEF decreases that fell below the lower limits of normal (33% to 48%). None of the patients developed clinically evident heart failure. Our results indicate that the combination of doxorubicin (50 mg/m2) plus paclitaxel (175 to 225 mg/m2) is effective and does not induce a clinically relevant cardiotoxicity.