HSCT May Improve Survival in Advanced Extranodal NK/T-Cell Lymphoma: A Single-Center Retrospective Study

Extranodal NK/T-cell lymphoma (ENKTCL) is a rare and aggressive lymphoid malignancy highly associated with Epstein-Barr virus (EBV) infection. Patients with stage III or higher disease often have a poor prognosis. This study retrospectively reviewed the treatment courses of 34 patients with relapsed/refractory (R/R) ENKTCL who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) at our center between January 2019 and July 2024. The results showed that in this study, the use of PD-1 inhibitors before transplantation, the number of treatment lines, and whether the plasma EBV was negative or not had no significant impact on OS and PFS. Patients achieving complete response (CR) or partial response (PR) prior to allo-HSCT exhibited a more favorable prognosis. Conversely, a history of chronic active EBV infection (CAEBV) before transplantation and EBV reactivation post-transplantation were associated with inferior survival, suggesting poor prognostic outcomes. Genetic susceptibility analysis revealed that patients with advanced ENKTCL frequently harbored hemophagocytic lymphohistiocytosis (HLH)-associated gene variants. LYST gene variants were the most commonly identified HLH-related alterations, and patients developing HLH experienced significantly higher non-relapse mortality (NRM). Furthermore, TP53 gene variants were associated with post-allo-HSCT relapse. In conclusion, Allogeneic HSCT may improve survival in selected high-risk, advanced-stage R/R ENKTCL patients. These single-center, retrospective findings are hypothesis-generating and require validation in larger, multi-center studies with longer follow-up.