Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation in Adult Acute Myeloid Leukemia: A Systematic Review

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative treatment for adult acute myeloid leukemia (AML), but its outcomes are influenced by donor selection, conditioning regimens, and patient-specific factors. This systematic review synthesizes recent evidence on survival, relapse, non-relapse mortality (NRM), and prognostic factors to guide clinical decision-making. A comprehensive search of PubMed, Scopus, Web of Science, Embase, and ClinicalTrials.gov (January 2020-August 2025) identified 10 studies meeting the inclusion criteria. Studies were evaluated for outcomes (overall survival (OS), disease-free survival (DFS), relapse, and NRM) and risk of bias using the Newcastle-Ottawa Scale (NOS) and Cochrane Risk of Bias (RoB) 2 tool. Haploidentical HSCT improved one-year survival (77.9% vs. 62.0% with chemotherapy) in elderly AML, with lower relapse (16.5% vs. 56.6%). Matched sibling donors (MSD) yielded superior two-year OS (62.4%) compared to unrelated/haploidentical donors, though relapse rates were comparable. Reduced-intensity conditioning (RIC) increased NRM in patients ≥70 years, while nonmyeloablative regimens improved tolerability. Transplantation in complete remission (CR) was critical (five-year OS: 58% vs. 6% for non-CR). Autologous HSCT outperformed allo-HSCT in acute promyelocytic leukemia (APL) complete remission 2 (CR2) (82.4% vs. 64.3% two-year OS). Allo-HSCT benefits intermediate/poor-risk AML, with MSD and CR transplantation offering optimal outcomes. Haploidentical HSCT is viable for older patients lacking matched donors. Future research should prioritize prospective trials to refine donor selection and conditioning strategies.