Abstract
Of 1774 patients with breast cancer given mitoxantrone (MTZ) with methotrexate (n = 492) or with methotrexate and mitomycin C (n = 1282), nine developed MDS/AML after a median of 2.5 years. Median duration of survival from diagnosis of MDS/AML was 10 months and six patients died. The crude incidence of developing MDS/AML after MMM or MM chemotherapy was 15 per 100,000 patient years follow-up, while the actuarial risk was 1.1% and 1.6% at 5 and 10 years respectively. MTZ-based regimens carry a 10 x higher risk of subsequent MDS/AML compared to that seen in the general population.