ALLOGENEIC BONE-MARROW TRANSPLANTATION IN FIRST REMISSION FOR CHILDREN WITH VERY HIGH-RISK ACUTE LYMPHOBLASTIC-LEUKEMIA - A RETROSPECTIVE CASE-CONTROL STUDY IN THE NORDIC COUNTRIES

Among children with high-risk (HR) ALL there are subgroups with very-h igh-risk (VHR) features and poor prognosis despite developments in con ventional chemotherapy for childhood ALL, We evaluated the outcome of VHR-ALL in children receiving allogeneic BMT (allo-BMT) in first remis sion (1CR) in a retrospective case-control study, In the population-ba sed ALL material of the five Nordic countries, 22 children with VHR-AL L have undergone allo-BMT in 1CR between 1981-1991, We compared the ou tcome in these 22 children with 44 closely matched control patients wh o received conventional chemotherapy on HR-ALL protocols, as well as w ith a group of 405 children representing the remaining HR-ALL patients in the Nordic ALL database, The disease-free survival at 10 years was 73% in children receiving allo-BMT in 1CR, 50% in the matched control s (P = 0.02), and 59% in the remaining HR-ALL patients, The good progn osis of the allo-BMT group was due to a low relapse rate of 9%, as opp osed to 41% in the group of matched controls, The superiority of allo- BMT as therapy in 1CR was mainly apparent in those with a very high WB C of greater than or equal to 100 x 10(9)/l at diagnosis; in the allo- BMT group 9/10 survived, as opposed to 8/20 of the matched controls (P = 0.03), We conclude that allo-BMT in 1CR should be seriously conside red for children with a matched sibling donor and a VHR-ALL with WBC o f greater than or equal to 100 and other established VHR criteria.