Allogeneic Hematopoietic Stem Cell Transplantation for Older Patients With Adult T-Cell Leukemia/Lymphoma: A Nationwide Retrospective Study.

Adult T-cell leukemia/lymphoma (ATL) is a peripheral T-cell lymphoma with a dismal prognosis. Although allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the only potentially curative treatment, its application in older patients is limited by treatment-related toxicity. Given the aging ATL population and the emergence of novel therapeutic agents, the role of allo-HSCT in elderly patients warrants reevaluation. We retrospectively analyzed 619 patients aged ≥60 years who underwent first allo-HSCT between 2010 and 2017. Patients were stratified into Group 1 (60-64 years, n = 385) and Group 2 (≥65 years, n = 234). The 3-year overall survival (OS) rate was significantly lower in Group 2 compared with Group 1 (23.5% vs. 32.8%, p < 0.001). Among patients transplanted in complete remission (CR), OS was lower in Group 2 than in Group 1 (32.2% vs. 40.2%), although this difference did not reach statistical significance (p = 0.091). In contrast, among non-CR patients, OS was significantly lower in Group 2 (17.3% vs. 26.5%, p = 0.007). Multivariable analysis identified age ≥65 years, HCT-CI ≥4, non-CR status, cord blood transplantation, and female-to-male donor-recipient mismatch as adverse prognostic factors. Notably, patients aged ≥70 years (n = 26) experienced particularly poor outcomes, with a 3-year OS of 11.5% and significantly higher non-relapse mortality, suggesting limited benefit of allo-HSCT in this subgroup. In summary, allo-HSCT is feasible for selected ATL patients aged ≥65 years, particularly those in CR. However, outcomes are substantially worse in older patients not in remission. The extremely poor prognosis among patients aged ≥70 years highlights the need for cautious decision-making and consideration of non-transplant alternatives in this population. These findings underscore the importance of individualized treatment planning for elderly ATL patients.