Comprehensive risk stratification for adult T-cell lymphoblastic lymphoma undergoing allogeneic haematopoietic stem cell transplantation.

Relapse remains the primary cause of transplant failure in T-cell lymphoblastic lymphoma (T-LBL) after allogeneic haematopoietic stem cell transplantation (allo-HSCT), yet prognostic data are scarce. We conducted a multicentre retrospective study of 104 adult T-LBL patients in complete metabolic remission (CMR) undergoing allo-HSCT. Pretransplant Deauville score (DS) was evaluated, and a risk model integrating DS, immunophenotype and donor type was developed. Patients with DS of 3 had significantly inferior 2-year overall survival (OS) (70.5% vs. 77.4% vs. 86.8%, p < 0.001), progression-free survival (PFS) (51.5% vs. 73.0% vs. 81.1%, p < 0.001) and higher relapse rates (42.1% vs. 15.4% vs. 9.8%, p < 0.001) compared to DS of 1-2. Multivariable analysis identified pretransplant DS, immunophenotype and donor type as independent risk factors for post-transplant relapse. These variables were integrated to construct a novel risk model stratifying patients into low- (66.0%), intermediate- (21.3%) and high-risk (12.7%) groups, strongly discriminating OS (p < 0.001), PFS (p < 0.001) and relapse (p < 0.001), with a C-index of 0.706. Internal validation confirmed that the risk stratification model had good discrimination, calibration and clinical benefit. Our findings propose a clinically actionable tool to identify high-risk T-LBL patients for tailored post-transplant strategies.