Allogeneic Stem Cell Transplantation for Acute Lymphoblastic Leukemia in Adolescents and Young Adults

Hematologic stem cell transplantation (HSCT) is the most potent consolidation therapy for high-risk acute lymphoblastic leukemia (ALL), but their outcomes and complications in adolescent and young adult (AYA) patients remain unclear. We compared outcomes after HSCT for ALL among children (age 1 to 9 years; n = 607), adolescents (age 10 to 19 years; n = 783), and young adults (age 20 to 29 years old, n = 603), based on Japanese nationwide registry data. The 5-year overall survival (OS) rate among AYA patients was worse than that of children, at 64% (95% confidence interval [CI], 60% to 68%). In the AYA, the 5-year treatment-related mortality (TRM) after HSCT was 19% (95% CI, 16% to 22%), significantly higher than that in younger patients. The most common cause of TRM in the AYA was infection. The relapse rate was not different across the 3 age groups. When focusing on older adolescents (age 15 to 19 years), there was no difference in outcomes between those treated in pediatric centers and those treated in adult centers. In conclusion, the AYA had a greater risk of nonrelapse death than younger patients, and infection was the most common cause. Further optimization is required for HSCT in AYAs with ALL.