Persistent Centre Effect but Improvement of Leukemia-Free Survival of HLA Identical Hematopoietic Stem Cell Transplantation for Adults with AML in First CR in Europe over the Period 1987–2005 an Analysis on Behalf of the ALWP of EBMT.

Background. Among major European centres which had undertaken more than 30 bone-marrow transplantations(BMT) between Jan 1, 1987, and Dec 31, 1995, the outcome of allogenic BMT for acute myeloid leukemia (AML) in first complete remission has been shown to be influenced by the centre in which the procedure is done. To determine whether similar variation exists 10 years later, we analysed leukaemia free survival (LFS), relapse incidence (RI) and treatment related mortality (TRM) across the same 13 transplant centres.

Methods. Thirteen centres were included in the analysis which enrolled 515 patients (aged 16–55 years), between 1987 and 1995, for acute myeloid leukaemia in first complete remission and 455 patients were enrolled between 1996 and 2005. Patients were followed from the date of transplantation to the time of event (Relapse and/or deaths). Regression models taking into account centre effect was adapted to the outcome and adjusted for relevant covariates

Findings The overall results at 5 years were 57% (95% CI 54–61) for leukaemia-free survival (LFS), 22% (19–25) for relapse incidence (RI), and 21% (18–24) for treatment related mortality (TRM) with a range for centres of 41–67%, 13–41%, and 13–41%, respectively. LFS at 5 years before 1995 was significantly lower 54% than after 1995 62% (p=0.02). Relapse Incidence at 5 years before 1995 was not significantly lower 23% than after 1995 21% (p=0.34). Treatment-related mortality incidence at 5 years before 1995 was not significantly lower 25% than after 1995 21% (p=0.13). Analysis showed the centre effect to be highly significant for LFS and TRM, but not for RI.

Interpretation These findings show that the results of BMT have improved over time in Europe. At the same time this study confirms a significant centre-specific variation in the success of bone transplantation in Europe. This effect has persisted despite advances in transplantation, which have lead to improvements in patient outcomes (leukaemia free survival and Treatment Related Mortality). Further studies are needed to elucidate the causes of this variation, with the goal of developing strategies to minimize the centre effect and ensure the best possible outcomes for all transplant recipients.