Ninety-four patients were entered in a clinical trial assessing the clinical activity of cyclophosphamide, doxorubicin, and prednisone (CAP) versus a combination of cyclophosphamide. 5-Fluorouracil, and prednisone (CFP) in patients with advanced breast cancer. Objective response rates were comparable, 49% for CFP and 46% for CAP. There was no statistical difference between the duration of response of the two regimens or in time to progression. Most importantly, survival differences were not apparent. Both regimens were clinically tolerable and toxicities, for the most part, were comparable. Thus, no therapeutic advantage existed for either of these polychemotherapy regimens in patients with advanced breast cancer.