Impact of Allogeneic Stem Cell Transplantation in First Complete Remission in Acute Myeloid Leukemia: A National Population-Based Cohort Study

To examine the outcomes of allogeneic stem cell transplantation (HSCT) in first complete remission (CR1) compared with chemotherapy alone in a population-based setting, we identified a cohort of patients with acute myeloid leukemia (AML) aged 15 to 70 years diagnosed between 2000 and 2014 in Denmark. Using the Danish National Acute Leukemia Registry, we compared relapse risk, relapse-free survival (RFS), and overall survival (OS) between patients with unfavorable cytogenetic features receiving postremission therapy with conventional chemotherapy only versus those undergoing HSCT in CR1. To minimize immortal time bias, we performed Cox proportional hazards regression, included date of allogeneic HSCT as a time-dependent covariate, and stratified the results by age (<60 or ≥60 years) and cytogenetic risk group. Overall, 1031 patients achieved a CR1. Of these, 196 patients (19%) underwent HSCT. HSCT was associated with a lower relapse rate (24% versus 49%) despite a similar median time to relapse (287 days versus 265 days). In all subgroups, the risk of relapse was lower and both RFS and OS were superior in recipients of HSCT (OS, adjusted mortality ratios: all patients, .54 [95% confidence interval (CI), .42-.71]; patients age <60 years, .58 [95% CI, .42-.81]; patients age ≥60 years, .42 [95% CI, .26-.69]; patients with intermediate-risk cytogenetics, .63 [95% CI, .43-.87]; patients with adverse-risk cytogenetics, .40 [95% CI, .24-.67]). In conclusion, in this population-based nationwide cohort study, HSCT was associated with improved survival in both younger and older patients and in patients with both intermediate and adverse cytogenetic risk.