Comparison of non-myeloablative and reduced-intensity allogeneic stem cell transplantation in older patients with myelodysplastic syndromes.

Allogeneic stem cell transplantation (HSCT) remains the only curative treatment for myelodysplastic syndromes (MDS) or myelodysplastic/myeloproliferative neoplasms (MDS/MPN) patients. The introduction of reduced intensity (RIC) and non-myeloablative (NMA) conditioning enabled HSCT in older or comorbid individuals representing the majority of patients. Studies comparing RIC and NMA conditioning are limited. We retrospectively analyzed 151 MDS or MDS/MPN patients older than 50 years who received NMA- or RIC-HSCT. Patients younger or older than 65 years at HSCT were analyzed separately. Patients receiving RIC-HSCT or NMA-HSCT were balanced in factors reflecting disease aggressiveness and the HCT-CI comorbidity score. The NMA conditioned patients had a higher incidence of graft rejection and chronic graft-vs-host disease. Cumulative incidence of relapse (CIR), non-relapse mortality (NRM) and overall survival (OS), did not differ significantly with regard to the conditioning regime in the whole cohort. In patients <65 years at HSCT, NMA conditioning associated with higher NRM and shorter OS by trend, while CIR was similar in both groups. In multivariable analyzes, the conditioning regimen remained a prognostic factor for NRM and OS in patients <65 years at HSCT. In MDS patients NMA and RIC conditioning result in similar disease control, but especially patients <65 years may benefit from RIC-HSCT.