AbstractObjectiveTo investigate the differences in efficacy and safety between haploidentical donor hematopoietic stem cell transplantation (HID‐HSCT) and matched sibling donor HSCT (MSD‐HSCT) in patients with T‐cell lymphoblastic lymphoma (T‐LBL).MethodsIn this retrospective analysis, we enrolled 38 patients who had undergone allogeneic HSCT at our institution between 2013 and 2021. The study participants included 28 patients who underwent HID‐HSCT and 10 patients who underwent MSD‐HSCT. We compared the patient characteristics and treatment effectiveness and safety between the two groups and evaluated potential prognostic variables for patients with T‐LBL.ResultsThe median follow‐up durations in the HID‐HSCT and MSD‐HSCT groups were 23.5 (range: 4–111) and 28.5 (range: 13–56) months, respectively. All patients showed full‐donor chimerism after hematopoietic stem cell transplantation (HSCT). Except for two patients in the HID‐HSCT cohort who developed poor graft function, all patients showed neutrophil and platelet engraftments after HSCT. The cumulative incidences of grades III–IV acute graft‐versus‐host disease were 37.5% and 28.57% in the HID‐HSCT and MSD‐HSCT groups, respectively (p= 0.84). The cumulative incidences of limited (34.13% vs. 28.57%,p= 0.82) and extensive (31.22% vs. 37.50%,p= 0.53) chronic graft‐versus‐host disease did not differ between the two cohorts. In the HID‐HSCT and MSD‐HSCT cohorts, the estimated 2‐year overall survival rates were 70.3% (95% confidence interval [CI]: 54.9%–90.0%) and 56.2% (95% CI: 31.6%–100%), respectively (p= 1.00), and the estimated 2‐year progression‐free survival (PFS) rates were 48.5% (95% CI: 32.8%–71.6%) and 48.0% (95% CI: 24.6%–93.8%), respectively (p= 0.94). Furthermore, the Cox proportional‐hazards model showed that a positive positron emission tomography/computed tomography (PET/CT) status before HSCT in patients who had completed chemotherapy was an independent risk factor for PFS in the multivariate analysis (p= 0.0367).ConclusionThis study showed that HID‐HSCT had comparable effectiveness and safety to MSD‐HSCT in treating T‐LBL. HID‐HSCT could serve as an alternate treatment option for T‐LBL in patients without an eligible identical donor. Achievement of the PET/CT‐negative status before HSCT may contribute to better survival.