Abstract • 33

MDS is highly malignant in children. The aim of our study was to evaluate the outcome of children with acute leukemia transformed from MDS in Belarus after Chernobyl catastrophe. 23 patients (pts) with MDS younger than 15 years were enrolled in the study between January 1994 and December 1998. The diagnosis included : RA - 3 cases, RAEB - 6 cases, RAEB-t - 3 cases, CMML - 8 cases, unclassified - 3 cases. AML and RAEB-t pts were treated according to AML-BFM-87 protocols, ALL-cases - according to ALL-BFM-90 protocols. 2 CMML pts were treated with HD methylprednisolone and 1CMML pt - with allo-BMT from HLA identical sibling. All patients received supportive therapy as indicated. The median age was 6 years(y) 9 months(m) (range 1y2m - 14y9m). 15 were boys. Disease progressed to ALL-L1 in 3 and to AML in 7 (M0 - 2, M1 - 4, M2 - 1). Survival for the all groups is 0.37, EFS for the group with transformation to RAEB-t / Leukemia is 0.31. Duration of survival is 22 months (range 2 - 56 months) and 22% remain disease free. We conclude that the majority (10 / 12 - 83%) of patients with MDS progress to higher FAB category or leukemia and confirm that the response and survival of these children after intensive chemotherapy is less effective than in patients presenting with de novo AML.