MYELODYSPLASIA AND ACUTE MYELOID-LEUKEMIA FOLLOWING ADJUVANT CHEMOTHERAPY FOR BREAST-CANCER USING MITOXANTRONE AND METHOTREXATE WITH OR WITHOUT MITOMYCIN

Background: Secondary acute myeloid leukaemia/myelodysplasia (t-AML, t -MDS) may occur following adjuvant chemotherapy for breast cancer and has been most frequently associated with alkylating agents. This compl ication is now being associated with an expanding list of chemotherape utic agents including topoisomerase II poisons. Mitoxantrone is an age nt with potential to cause t-AML and t-MDS and which is being used inc reasingly in the treatment of breast cancer. Patients and methods: Fif ty-nine patients who received mitoxantrone as part of adjuvant chemoth erapy for breast cancer between 1986 and 1992 were studied to determin e the incidence of t-AML and t-MDS. Results: With a median follow-up o f 72 months, 2 cases of t-AML and 1 of t-MDS have occurred. Conclusion s: This 5% incidence of t-AML and t-MDS is high and likely related to mitoxantrone. Whereas this agent is effective and has acceptable toxic ity in advanced disease, its incorporation into adjuvant treatment reg imens cannot be recommended based on this experience.