Acute leukemia as a complication of long-term treatment of advanced breast cancer.

Acute nonlymphocytic leukemia occurred in four women after long-term therapy for advanced breast cancer. The patients had inoperable/metastatic breast cancer that had been well-controlled with chemotherapy for many years (7 years and 4 months, 7 years and 1 month, 6 years and 3 months, and 4 years and 7 months, respectively). Two of the patients had also received extensive radiotherapy. The chemotherapeutic agent that all four patients had received in common was cyclophosphamide.