ACUTE MYELOID-LEUKEMIA AND MYELODYSPLASIA FOLLOWING INTENSIVE CHEMOTHERAPY FOR BREAST-CANCER

Two major classes of therapy-related acute myeloid leukemias (t-AML) a nd myelodysplastic syndromes (t-MDS) have been described following the use of conventional doses of alkylating agents and epipodophyllotoxin s. They are characterized by distinct clinical presentations and chrom osomal abnormalities. We report 2 cases of t-AML and 1 case of t-MDS i n 3 out of 36 women who underwent high-dose chemotherapy and attempted ABMT for breast cancer. Two patients developed t-AML 4 and 8 months f ollowing the initiation of high-dose chemotherapy with or without ABMT . The third patient developed t-MDS 23 months following dose-intensive chemotherapy and ABMT. Cytogenetic studies of the marrow metaphase ch romosomes from the two patients who developed t-AML, including FISH an alysis in 1 patient, showed t(9;11)(p22,q23) and abnormal chromosome 6 (ring chromosome). Neither patient had a preleukemic phase. Cytogenet ic studies from the third patient who developed t-MDS showed abnormali ties of chromosome 5 (-5) and a derivative of chromosome 17. The use o f multiple chemotherapeutic agents in all 3 patients makes it difficul t to attribute the development of these cases of t-MDS/t-AML to a sing le chemotherapeutic agent. The possible role of dose-intensive chemoth erapy in the development of these secondary malignancies is discussed.