Three hundred thirty-one women with metastatic breast cancer were randomized to receive combination chemotherapy with either cyclophosphamide, Novantrone (mitoxantrone; Lederle Laboratories, Wayne, NJ), and fluorouracil (CNF) or cyclophosphamide, Adriamycin (doxorubicin; Adria Laboratories, Columbus, OH), and fluorouracil (CAF). Patients could not have had prior chemotherapy, although adjuvant chemotherapy was acceptable. Initial doses were 500 mg/m2 of cyclophosphamide and 500 mg/m2 of fluorouracil with either 10 mg/m2 of mitoxantrone or 50 mg/m2 of doxorubicin, administered intravenously (IV) on day 1 and repeated every 3 weeks. There were no statistically significant differences in pretreatment or prior therapy characteristics between the groups. For patients assigned to the CNF and CAF groups, respectively, 25 (18%) were premenopausal, 39 (40%) were estrogen receptor (ER) negative, 39 (38%) had a disease-free interval less than 1 year, and 24 (26%) had received prior adjuvant chemotherapy. All patients were compared for response rate, duration of response, time to progression or death, time to treatment failure (TTF), and survival. None of these parameters were statistically significant favoring one regimen over the other. The response rate (complete [CR] and partial response [PR]) was 29% for the CNF group (95% confidence interval of 22% to 37%) and 37% for the CAF group (95% confidence interval of 29% to 45%). The median response duration and TTF were 171 days and 125 days for the CNF group and 254 days and 147 days for the CAF group, respectively. The median survival times for the CNF group and the CAF group were 377 and 385 days, respectively. The major dose-limiting toxicity for both regimens was leukopenia, manifested as granulocytopenia. The incidence of stomatitis/mucositis was 10% in the CNF group and 19% in the CAF group. Alopecia occurred in 49% of CNF patients (severely for 4%) and in 86% of CAF patients (severely for 39%). Nausea/vomiting occurred in 80% of CNF patients and in 81% of CAF patients; the degree of severity was also comparable. There was significantly less cardiotoxicity observed in the CNF group compared with the CAF group. Although CNF is somewhat less effective in overall response rate, survival curves are identical. CNF can be offered to patients who reject anthracycline-containing regimens because of fear of alopecia.