Mitomycin C in metastatic breast cancer resistant to hormone therapy and conventional chemotherapy.

Mitomycin C was administered to 22 patients with metastatic breast cancer, refractory to hormonal therapy and conventional chemotherapy. Treatment was given by intravenous bolus injection at 20 mg/m2 of the drug and repeated at 6-week intervals. The overall response rate was 23%. Two complete remissions were seen in soft tissue lesions. Leukopenia occurred in 68% of the patients, thrombocytopenia in 36%, and anemia in 14%. One case of cardiotoxicity after previous treatment with adriamycin was observed. We conclude that mitomycin C is an active agent in disseminated breast cancer resistant to hormone therapy and chemotherapy. Combination of mitomycin C with other chemotherapeutic drugs will be tested.