The effect of graft‐versus‐host disease on outcomes after allogeneic stem cell transplantation for refractory lymphoblastic lymphoma in children and young adults

Background Patients with relapsed or refractory lymphoblastic lymphoma (LBL) have a poor prognosis. The efficacy of allogeneic blood stem cell transplantation for treatment of this disease remains unclear in terms of transplantation‐related toxicity. Acute and chronic graft‐versus‐host diseases (GVHD) are both harmful to patients after allogeneic transplantation, but may have some positive effects through a substitute graft‐versus‐lymphoma effect. Methods To investigate the effect of GVHD on the survival of patients with refractory LBL, we retrospectively studied the outcomes of 213 patients with LBL who underwent first allogeneic stem cell transplantation before the age of 18 years, between 1990 and 2015 in Japan. Results The five‐year overall survival (OS) and event‐free survival rates after stem cell transplantation were 50.3% (95% confidence interval [CI], 43.2‐56.9) and 47.8% (95% CI, 40.8‐54.4), respectively. In univariate landmark analyses, the probability of OS was significantly better in patients with aGVHD than in those without ( P  = 0.002, five‐year OS 58.1% vs 39.0%). The probability of OS was also better in patients with cGVHD than in those without ( P  = 0.036, five‐year OS 72.2% vs 54.7%). Multivariate analysis demonstrated that only aGVHD was associated with better OS (hazard ratio, 0.63; 95% CI, 0.42‐0.94, P  = 0.024). Progression and recurrence statuses at SCT were associated with poor prognosis. The patients with grade II aGVHD showed the best prognosis (five‐year OS: 65.6%). Conclusion Our results suggest that the occurrence of aGVHD may be associated with better outcomes in patients with relapsed/refractory LBL who undergo allogeneic transplantation.