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

Summary 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.