Hematopoietic Cell Transplantation for Myelodysplastic Syndromes

Allogeneic hematopoietic cell transplantation (HCT) offers the only potential cure for patients with myelodysplastic syndromes (MDS). However, with current approaches to HCT, many older patients with comorbidities are poor HCT candidates, and treatment-related morbidity and mortality may offset benefit for patients with lower-risk disease. Consequently, selection of patients with MDS for HCT should take into consideration disease risk category including mutational status, HCT comorbidity index, functional status, donor options, and available institutional resources. Formal geriatric assessment may further guide use of HCT and, if HCT is chosen, selection of conditioning intensity. Patients with higher-risk MDS should be considered for HCT at the time of diagnosis, whereas expectant nontransplant management is more appropriate for those with lower-risk disease. A high blast burden at the time of HCT increases the risk of subsequent relapse; however, the role of pretransplant cytoreductive therapy and the regimen of choice remain controversial. Patients with MDS younger than 65 years and with an HCT comorbidity index <= 4 may benefit from more intense conditioning regimens. The presence of complex or monosomal karyotype or mutations in TP53, DNMT3A, or other genes identify patients with poorer outcomes following HCT. Patients with TP53 mutations have particularly poor survival, and should be enrolled in clinical trials whenever possible. Several important HCT studies are ongoing and will better define the role of HCT inMDS as well as the value of pretransplant cytoreductive therapy or post-transplant relapse-prevention strategies. Given the apparent underuse ofHCT in eligible patients and lowenrollment inMDSHCT clinical trials to date, timely referral of patients with MDS to such trials and HCT programs is critical.