The Impact of Center Experience on Results of Reduced Intensity – Allogeneic Hematopoietic Stem Cell Transplantation. A Survey From the Acute Leukemia Working Party (ALWP) of the European Group for Blood and Marrow Transplantation (EBMT)

Abstract 3517

Allogeneic hematopoietic stem cell transplantation with reduced intensity conditioning (RIC-HSCT) is increasingly applied for the treatment of patients with acute myeloid leukemia. However, the procedure is heterogeneous with no standards based on randomized trials being elaborated so far. Hence, particular therapeutic decisions are in major part based on individual experience.

The goal of this study was to evaluate the impact of center experience on outcome of RIC-HSCT. Based on the registry of ALWP of the EBMT, we analyzed results of 1413 HLA-matched related (n=1058) or unrelated (n=355) transplantations performed in 203 European centers between 2001 and 2007. Only patients with AML in first complete remission were included. Median recipient age was 55 years (range, 18–77 y.). Centers were categorized by quintiles according to the number of RIC-HSCT procedures in a study period.

The 2 years probability of leukemia-free survival (LFS) after RIC-HSCT performed in centers with the lowest activity (1^st quintile, ≤ 15 procedures/7 years) equaled 43% compared to 55% in the remaining ones (p<0.001). The incidence of non-relapse mortality (NRM) was 24% and 15%, respectively (p=0.004). In a multivariate model adjusted for other potential prognostic factors low RIC-HSCT activity was associated with decreased chance of LFS (HR=0.69, p<0.001) as well as increased risk of NRM (HR=1.69, p=0.001) and relapse (HR=1.37, p=0.01). No significant differences were found between centers belonging to the 2^nd -5^th quintile.

We conclude that center experience is a strong predictor of outcome and should be considered for future analyses evaluating results of RIC-HSCT.