Prognostic factors and a novel scoring system for allogeneic hematopoietic stem cell transplantation in patients aged 70 years or older: a nationwide registry analysis in Japan.

Despite recent advances, data on allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients aged ≥70 years remain limited. We identified prognostic factors and developed a risk score to guide transplant eligibility. Using the Japanese Transplant Registry Unified Management Program, we retrospectively analyzed 929 patients aged ≥70 years who underwent their first allo-HSCT for hematologic malignancies between 2000 and 2022. Prognostic factors were identified by multivariate Cox regression to construct a scoring system. The median patient age was 71 years (range, 70-88), with acute myeloid leukemia being the most common disease. The 2-year overall survival (OS) rate was 34.2%. Multivariate analysis identified age ≥75 years, ATL, lymphoma, high disease risk, hematopoietic cell transplant-specific comorbidity index ≥5, and performance status ≥2 as adverse factors. Using the hazard ratio-based scoring system derived from multivariate analysis, patients were stratified into low- (0), intermediate-1- (1), intermediate-2- (2-3), and high-risk (4-5) groups, with 2-year OS rates of 57.1%, 35.0%, 18.3%, and 2.5%, respectively (p < 0.01). We identified prognostic factors and developed a scoring system stratifying survival in patients aged ≥70 years, potentially facilitating the selection of older candidates most likely to benefit from allo-HSCT.