An effective low‐dose mitomycin regimen for hormonal‐ and chemotherapy‐refractory patients with metastatic breast cancer

Abstract

Ninety evaluable metastatic breast cancer patients refractory to hormonal therapy and combinations of cyclophosphamide, methotrexate, 5‐fluorouracil, and doxorubicin were treated with a low‐dose mitomycin regimen, i.e., 10 mg/m2 intravenously every 28 days. In order to minimize thrombocytopenia, dose de‐escalations related to platelet counts were made. One patient (1%) had a complete response and 17% had partial responses for a median duration of 4 months. The time to progression for the responders and stabilized patients was similar; however, the responders and stabilized patients lived significantly longer than did the progressors. Hematologic toxicity was minimized because of planned de‐escalations in mitomycin dosage. Perivenous ulceration, both immediate and delayed (8%), congestive heart failure (2%), and heart‐renal failure with malignant hypertension (2%) resulted in significant morbidity, including two drug‐related deaths. Although mitomycin dosages were successfully titrated according to platelet counts in this group of chemotherapy‐refractory patients, prolonged use of this drug in adjuvant or early metastatic breast cancer patients is not recommended because of potentially irreversible thrombocytopenia. Copyright © 1983 American Cancer Society