Failure to reach hematopoietic allogenic stem cell transplantation in patients with myelodysplastic syndromes planned for transplantation: a population-based study

The only potential cure for patients with myelodysplastic syndrome (MDS) is allogeneic hematopoietic stem cell transplantation (HCT). However, a proportion of patients who are HCT candidates do not finally get transplanted. This population-based study aimed to characterize HCT candidates were attempting to reach HCT fail and to identify causes and risk factors for failure. Data were collected from (1) the national Swedish registry, enrolling 291 transplant candidates between 2009–2018, and (2) Karolinska University Hospital, enrolling 131 transplantation candidates between 2000 and 2018. Twenty-five % (nation-wide) and 22% (Karolinska) failed to reach HCT. Reasons for failure to reach HCT were progressive and refractory disease (47%), no donor identified (22%), identification of comorbidity (18%), and infectious complications (14%). Factors associated with failure to reach HCT were IPSS-R cytogenetic risk-group very poor, mixed MDS/MPN disease, low blast count (0–4.9%), and low hemoglobin levels (≤7.9 g/dL). Transplanted patients had a longer overall survival (OS) compared to patients who failed to reach transplantation (83 months versus 14 months; p < 0.001). The survival advantage was seen for the IPSS-R risk groups intermediate, high, and very high. This study demonstrated that a high proportion of HCT-candidates fail to reach HCT and underlines the difficulties associated with bridging MDS patients to HCT.