Long-term outcomes after allogeneic versus autologous haematopoietic stem cell transplantation for T-lymphoblastic lymphoma.

T-lymphoblastic lymphoma (T-LBL) is an aggressive malignancy with a high relapse risk despite intensive therapy. The optimal transplant strategy remains uncertain. We retrospectively analysed 81 patients with T-LBL undergoing haematopoietic stem cell transplantation (HSCT) (59 allogeneic [allo-HSCT] and 22 autologous [auto-HSCT]). Survival outcomes were evaluated using Kaplan-Meier and competing-risk methods. Multivariable Cox regression, propensity score matching and landmark analyses at 12 months were performed. At 3 years, overall survival (OS) was comparable between allo-HSCT and auto-HSCT (76.0% vs. 77.0%; p = 0.890), while progression-free survival (PFS) was numerically higher following allo-HSCT (77.0% vs. 58.7%; p = 0.141). The cumulative incidence of relapse tended to be lower after allo-HSCT (18.6% vs. 30.5%; p = 0.129), with similar non-relapse mortality. Landmark analyses suggested a time-dependent pattern, with divergence in PFS beyond 12 months. In multivariable analyses, allo-HSCT (hazard ratio [HR] 0.34; p = 0.037) and complete remission at transplantation (HR 0.23; p = 0.001) were independently associated with improved PFS, highlighting disease status as a key determinant. Allo-HSCT showed a trend towards improved disease control without increased non-relapse mortality. This effect may be influenced by disease status at transplantation. Findings should be interpreted cautiously and require prospective validation.