Mitomycin in metastatic breast cancer refractory to hormonal and combination chemotherapy.

Forty-three patients with evaluable metastatic breast cancer refractory to hormonal agents and extensive combination chemotherapy including doxorubicin were treated with mitomycin, 20 mg/m2 intravenously every 6 weeks. There were five partial responses (12%) and three minor responses (7%), with a mean time to progression of 5 months and 3.5 months, respectively. Thrombocytopenia was the major dose-limiting toxicity, and myelosuppression was cumulative. Cardiac dysfunction was observed in 12% of patients. Mitomycin had some antitumor activity in this group of metastatic breast cancer patients refractory to extensive combination chemotherapy including doxorubicin.