Clinical Relevance of Transplant Conditioning Intensity Score-Based Refinement of Conditioning Intensity in Cord Blood Transplantation for Myelodysplastic Syndrome.

Cord blood transplantation (CBT) is an alternative donor strategy for patients with myelodysplastic syndrome (MDS). To clarify the impact of the transplant conditioning intensity (TCI) score, we examined 1127 patients with de novo MDS who underwent CBT between 2008 and 2022, using a nationwide registry database. Patients were stratified into three age groups: <50 years (Younger group, n = 256), 50 to 64 years (Middle group, n = 545), and 65 to 74 years (Older group, n = 326). In the Older group, the multivariate analysis revealed that TCI score of 4.5 to 5.0 correlated with higher overall mortality (OM) than TCI score of 3.5 to 4.0 (hazard ratio 1.61, 95% confidence interval 1.02 to 2.49, P = .032). In the Middle group, TCI score of 4.5 to 5.0 was associated with lower relapse incidence than TCI score of 3.5 to 4.0 (hazard ratio 0.64, 95% confidence interval 0.45 to 0.91, P = .014) but did not have any significant impact on OM. In the Younger group, no significant difference was observed in OM, relapse incidence, and nonrelapse mortality. Collectively, these findings support the utility of TCI score-based conditioning stratification as a practical framework for guiding age-adapted conditioning regimen selection in patients with de novo MDS undergoing CBT.