INTENSIVE CHEMOTHERAPY IN CHILDHOOD MYELODYSPLASTIC SYNDROME - A COMPARISON WITH RESULTS IN ACUTE MYELOID-LEUKEMIA

Myelodysplastic syndrome (MDS) in children is often considered as a va riant of acute myeloid leukemia (AML) and frequently treated as such. However, there are very few reported data on the outcome following AML treatment. We analyzed 20 consecutive cases of de novo MDS treated in Denmark according to the NOPHO AML protocols. The results were compar ed with those obtained in 31 children with de novo AML treated with th e same protocols, and with the outcome in 10 children with MDS who rec eived allogeneic bone marrow transplantation (BMT) without prior AML t herapy. Distinction between MDS and AML was made morphologically accor ding to the FAB criteria. All children were followed for at least 37 m onths. The proportion of complete remission in MDS and AML was 35% vs 74% (P=0.005), resistant disease 25% vs 10% (P=0.14), death in cytopen ia 40% vs 16% (P=0.06), and 3-year survival 15% vs 35% (P=0.11), respe ctively. Duration of treatment-related cytopenia was similar in MDS an d AML, except for a longer period of leukopenia in MDS following the s econd course of induction. Seven of 10 MDS children receiving BMT with out prior chemotherapy are long-term survivors. Our data suggest that conventional AML regimens are associated with a low rate of complete r emission, a high risk of death in cytopenia, and a limited curative po tential in childhood MDS. Allogeneic BMT was in contrast associated wi th a high survival rate, BMT may, at least in some patients, be perfor med successfully without prior induction chemotherapy. The different r esponse to therapy in MDS and AML may reflect fundamental biological d ifferences between the two conditions.