Mitomycin C and vinblastine in the treatment of advanced breast cancer.

Forty-nine women with progressive metastatic breast cancer, extensively pretreated, received mitomycin C 12 mg/m2 and vinblastine 6 mg/m2 intravenously every 3 weeks. Eleven patients responded, giving a response frequency of 22%. Considering only the 40 patients evaluable after two or more courses of treatment, the response frequency is 27.5%. Responses occurred predominantly at soft tissue sites. Subjective toxicity was mild.