Efficacy of allogeneic hematopoietic stem cell transplantation depends on cytogenetic risk for acute myeloid leukemia in first disease remission: a metaanalysis

BACKGROUND: The efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) from a human leukocyte antigen-identical sibling donor remains controversial for patients with acute myeloid leukemia (AML) in first complete disease remission (CR1). Because the karyotype identified at diagnosis is the most relevant prognostic factor for AML, it should be possible to assess the efficacy more accurately on the basis of cytogenetic risk. METHODS: The authors performed a metaanalysis of five studies, which employed both natural randomization based on donor availability and intention-to-treat analysis, with overall survival as an outcome of interest. Metaregression analysis was then performed to identify the efficacy for patients stratified into the favorable, intermediate, and poor cytogenetic risk groups. RESULTS: For the entire cohort, there was a statistically significant advantage with allo-HSCT in terms of overall survival with a summary hazard ratio of 1.15 (95% confidence interval, 1.01-1.32, P = 0.037) for the random-effect model. Metaregression analysis showed a significant coefficient of +0.24 for the poor cytogenetic risk group, and -0.25 for the favorable cytogenetic risk group, indicating that the benefit of allo-HSCT was further increased for the former, and lost for the latter. The coefficient for the intermediate cytogenetic risk group was +0.09, and was not statistically significant. CONCLUSIONS: These findings suggested that the efficacy of allo-HSCT for patients with AML in CR1 depended on cytogenetic risk. The beneficial effect of allo-HSCT was yielded for the poor risk group, and probably for the intermediate risk groups, but was absent for the favorable risk group.