Age-Related Considerations in Allogeneic Hematopoietic Stem Cell Transplantation for Acute Leukemia: A 10-Year Retrospective Study

<b>Background:</b> Allogeneic hematopoietic stem cell transplantation (HSCT) has long been a curative intervention for acute leukemia, though outcomes in older patients remain suboptimal due to higher non-relapse mortality (NRM) and relapse rates. Innovations in conditioning regimens and supportive care have made HSCT accessible to patients over 50, but age-related disparities in outcomes persist. <b>Materials and Methods:</b> This 10-year retrospective cohort study reviewed all patients who underwent first-time allogeneic HSCT for acute leukemia. Patients were stratified by age at HSCT (≥ 50 years and < 50 years), and outcomes were assessed for overall survival (OS), disease-free survival (DFS), NRM, and relapse incidence (RI). <b>Results:</b> Of the 1199 patients, 152 were 50 years or older. Five-year OS rates were markedly lower in patients ≥ 50 years compared to younger patients (48.70% vs. 59.35%; <i>P</i>= 0.024 for AML and 23.60% vs. 41.96%; <i>P</i>= 0.025 for ALL). Moreover, older patients demonstrated significantly higher NRM rates (35.95% vs. 23.53%; <i>P</i>= 0.045 for AML and 78.14% vs. 26.76%; <i>P</i>= 0.005 for ALL) and a notably increased incidence of grade III-IV acute graft-versus-host disease (aGVHD). Interestingly, no significant differences were observed between the two age groups regarding DFS rates and RI. <b>Conclusion:</b> Older acute leukemia patients undergoing allogeneic HSCT face significant challenges, including elevated NRM and GVHD rates. While relapse rates were comparable, survival outcomes favored the younger cohort. These findings emphasize the need for age-adapted transplantation strategies, using reduced-intensity conditioning (RIC) regimens and further research to refine risk stratification and improve management approaches for older patients.