Allogeneic Hematopoietic Cell Transplantation for Adolescent and Young Adult Patients with Acute Myeloid Leukemia.

Limited data exist regarding the outcomes of allogeneic hematopoietic cell transplantation (allo-HCT) among adolescent and young adult (AYA) patients with acute myeloid leukemia (AML). Here we analyzed the features and outcomes of AYA patients with AML who had achieved complete remission (CR) and those who had not (non-CR) at allo-HCT. We retrospectively analyzed 2350 AYA patients with AML who underwent allo-HCT with a myeloablative conditioning regimen and who were consecutively enrolled in the Japanese nationwide HCT registry. The difference in overall survival (OS) between younger (age 16 to 29 years) and older AYA (age 30 to 39 years) patients in CR at transplantation was not significant (70.2% versus 71.7% at 3 years; P = .62). Meanwhile, this difference trended toward a statistical significance between younger and older AYA patients in non-CR at transplantation (39.5% versus 34.3% at 3 years; P = .052). In AYA patients in CR and non-CR, the age at transplantation did not affect relapse or nonrelapse mortality (NRM). In AYA patients in CR, no difference in OS was observed between those who received total body irradiation (TBI) and those who did not (71.1% versus 70.5% at 3 years; P = .43). AYA patients who received TBI-based conditioning had a significantly lower relapse rate and higher NRM than those who underwent non-TBI-based conditioning (relapse: 19.8% versus 24.1% at 3 years [P = .047]; NRM: 14.7% versus 11.1% at 3 years [P = .021]). In contrast, among the non-CR patients, there were no differences between the TBI and non-TBI groups with respect to OS (P = .094), relapse (P = .83), and NRM (P = .27). Our data indicate that outcomes may be more favorable in younger AYA patients than in older AYA patients in non-CR at transplantation, and that outcomes of TBI-based conditioning could be comparable to those of non-TBI-based conditioning for AYA patients.