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 doselimiting 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.