Optimizing Timing and Preparation for Allogeneic Hematopoietic Stem Cell Transplantation in Higher-Risk Myelodysplastic Syndromes

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only curative treatment for higher-risk myelodysplastic syndromes (MDS), but optimal timing and donor selection remain controversial. We conducted a retrospective analysis of 70 higher-risk MDS patients classified by the revised International Prognostic Scoring System (IPSS-R) undergoing allo-HSCT. Patients were stratified by: 1) the interval from diagnosis to allo-HSCT (early: <6 months vs later: ≥6 months); 2) pre-transplant treatment cycles (fewer: <2 vs more: ≥2); 3) remission status (complete remission [CR] / partial remission [PR] vs non-remission [NR]), and 4) donor type (sibling vs unrelated cord blood [UCB]). The results showed a significantly higher 3-year overall survival (OS) in the early HSCT group (70% vs 50%, p = 0.05) with lower transplant-related mortality (TRM) (22.7% vs 46.5%, p = 0.0205). Although more pre-transplant treatment cycles were linked to a lower relapse rate (2.3% vs 15.4%, p = 0.0403), they did not significantly affect OS or TRM. Early HSCT emerged as the only significant factor influencing both OS (Hazard Ratio [HR] 2.84, p = 0.01) and TRM (HR 3.21, p = 0.01). While no significant differences were noted between sibling HSCT and unrelated cord blood transplantation (UCBT) for OS and TRM, UCBT demonstrated a lower incidence of chronic graft-versus-host disease (cGVHD) (19.0% vs 52.9%, p = 0.003). Our findings suggest early allo-HSCT may optimize outcomes in higher-risk MDS. In settings where sibling donors are unavailable, UCBT could serve as a potential alternative, though this observation requires validation in prospective multicenter studies to account for inherent selection biases and confounding factors.