Results of allogeneic bone marrow transplantation for acute leukemia have improved in Europe with time--a report of the acute leukemia working party of the European group for blood and marrow transplantation (EBMT).

To evaluate whether the results of bone marrow transplantation have improved in Europe with time, we analyzed the outcome for 2195 patients with acute leukemia. 1405 had acute myeloid leukemia (AML) and 790 had acute lymphoblastic leukemia (ALL), and were allografted in first complete remission between September 1979 and December 1991 with marrow from an HLA-identical sibling donor. We found a continuing improvement more evident since 1987 for AML and since 1986 for ALL. A substantial reduction in the 3 years transplant related mortality (TRM): 26 vs 39% for AML (P = 10(-4)), and 25 vs 39% for ALL (P = 10(-4)), has resulted in an increase of the 5-year actuarial leukemia-free survival (LFS). 57 vs 45% for AML (P < 10(-4)) and 54 vs 45% (P = 10(-4)) for ALL. Four important changes have occurred. (1) Graft-versus-host disease (GVHD) prevention has involved an increased use of cyclosporin A (CsA) alone and subsequently its use in combination with methotrexate: this was associated with lower TRM both in AML and ALL; (2) Use of total body irradiation as pretransplant regimen has decreased; (3) a shorter interval from remission to BMT is more common; (4) an older population of patients has undergone BMT. Multivariate analyses were performed separately in AML and ALL. In AML four variables significantly influenced TRM favorably: year of BMT (P = 10(-4)), younger age at BMT (P = 10(-4)), prevention of GVHD including CsA (P = 0.008), sex match other than female donor to male recipient (P = 0.002). The relapse incidence (RI) was lower in patients with FAB M1-2-3 vs M4-5 (P = 0.0004). The LFS improved by year of BMT (P = 0.0004), younger age at BMT (P = 10(-4)), prevention of GVHD including CsA (P = 0.01), FAB M1-2-3 (P = 0.03). In ALL, three variables were associated with a lower TRM: year of BMT (P = 10(-4)), younger age at BMT (P = 10(-4)), sex combination other than female to male (P = 0.008). The LFS was better after 1986 (P = 0.0004) and in younger patients (P = 10(-4)). However a better outcome after 1986/87 was observed in patients receiving the same GVHD prophylaxis: therefore, other unidentified factors resulting in better patient care have also contributed to this. The improved results of allogeneic BMT are entirely related to a reduction in TRM without loss of the antileukemic effect since relapse incidence has not changed over the years.