Optimizing stem cell transplantation in myelodysplastic syndromes: Unresolved questions

Purpose of Review: Allogeneic hematopoietic stem cell transplantation (HCT) is the only curative therapy for myelodysplastic syndrome (MDS). Recent efforts to optimize the curative potential of transplant have focused on pretransplant therapy options, the use of predictive models to improve patient selection, and transplant modifications using reduced conditioning intensity. This review highlights strategies to optimize transplant for MDS and identifies unresolved questions. Recent Findings: Debate surrounding pretransplant therapy and HCT conditioning intensity for MDS continues. The current literature fails to identify a superior pretransplant treatment regimen; however, for treated patients achieving complete remission, the data suggest that myeloablative conditioning may not be required for successful transplant outcomes. Patient selection for transplant is also critical, and predictive tools (WHO classification-based prognostic scoring system and hematopoietic cell transplantation comorbidity index) have helped identify patients who may derive the most transplant benefit. Summary: Prospective trials regarding optimal pretransplant therapy, utilization of patient selection tools, and conditioning intensity are warranted to improve transplant outcomes in MDS. Until those data are mature, current data suggest we initiate pretransplant therapy that minimizes toxicity and improves responses, try to optimize our patient selection using comorbidity (hematopoietic cell transplantation comorbidity index) and other predictive tools (WHO classification-based prognostic scoring system), and consider reduced intensity conditioning/nonmyeloablative conditioning in patients who have achieved a complete remission prior to transplant.