Abstract
The optimal intensity of conditioning regimens for allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients diagnosed with myelodysplastic syndromes with excess blasts (MDS-EB) remains debated. We retrospectively analyzed the clinical outcomes of 102 MDS-EB patients who received an individualized conditioning protocol based on age and comorbidity, including busulfan, fludarabine, cytarabine, and low-dose total body irradiation (TBI). All patients achieved successful engraftment, with a median time to neutrophil and platelet engraftment of 12 and 13 days, respectively. The cumulative incidence of grade II-IV acute graft-versus-host disease (GVHD) at 180 days was 16.9%, while moderate-to-severe chronic GVHD at 2 years occurred in 15.0% of patients. After a median follow-up of 23 months, the 2-year relapse incidence was 11.5%. The 2-year overall survival (OS), progression-free survival (PFS), and GVHD-free/relapse-free survival (GRFS) were 81.9%, 77.3%, and 66.4%, respectively. The very high-risk subgroup of the International Prognostic Scoring System for MDS (IPSS-M) exhibited significantly higher relapse rates compared with the lower-risk groups (17.8% vs 2.4%, P = 0.03). Multivariate analysis identified IPSS-M as the only independent predictor of PFS (hazard ratio (HR) = 3.30, P = 0.04), whereas transplant conditioning intensity (TCI) showed no association with survival outcomes. These findings suggest that the age- and comorbidity-adjusted conditioning regimen achieves high engraftment rates, low relapse, and favorable survival in MDS-EB patients, with disease biology (IPSS-M) outweighing conditioning intensity in prognostic relevance.