Mitomycin C in the chemotherapy of advanced breast cancer.

Mitomycin C is a chemotherapeutic agent active against breast cancer. Because one of its potential toxicities is prolonged myelosuppression, it is not generally used in first-line chemotherapy regimens. However, several mitomycin C-containing combinations are effective in the salvage therapy of patients that have failed to respond to previous regimens. The choice of a salvage combination depends on the previous treatment received by an individual patient. Patients failing regimens based on CMF (cyclophosphamide, methotrexate, 5-fluorouracil [5-FU]) should be treated with combinations incorporating drugs not included in CMF. Active agents in this setting include mitomycin C, doxorubicin, and vinca alkaloids (usually vinblastine). Patients treated with combinations based on doxorubicin and cyclophosphamide (AC) are frequently administered a CMF-type regimen after a cumulative dose of doxorubicin has been reached. Therefore, they have often received doxorubicin, cyclophosphamide, methotrexate, and 5-FU. Salvage chemotherapy for failing patients in this setting is generally based on mitomycin C and/or vinblastine. Selection of a chemotherapeutic regimen for breast cancer must take into account the palliative nature of chemotherapy in this disease. Consequently, effective combinations that can be administered with minimal disruption of a patient's life-style are preferred.