Allogeneic Haematopoietic Cell Transplantation in Extranodal Natural Killer/T-cell Lymphoma.

Background Extranodal NK/T-cell lymphoma (ENKL) is aggressive and resistant to chemotherapy and radiotherapy. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative treatment to high risk lymphomas, owing to its associated graft-versus-lymphoma (GVL) effect. However, its application to ENKL is limited. Methods A systematic review and data analysis was performed to evaluate the performace of allo-HSCT to ENKL using literatures from PubMed, Medline and Embase from January 2000 to December 2019 in English language. Results Totally 136 cases from 17 eligible publications were included in this study. 1) after allo-HSCT, by the average follow-up time of 34 months (range: 1-121 months), 37.5% (52) of 136 patients had acute graft-versus-host disease (GVHD), 31.6% (43) had chronic GVHD; 2) when reported, 35.3% (48) of the patients had relapsed, but 2 of which relapsed only locally and achieved complete remission (CR) again with additional irradiation, chemotherapy, donor lymphocyte infusions to one of them and rapid tapering and discontinuation of cyclosporine to the other, earning more than one year's extra survival; 3) of the 136 patients, 51.5% (70) died because of primary disease progression (42.9%), infection (20.0%), GVHD (11.4%), organ failure (7.1%), hemorrhage (4.3%), and others (not specified/unknown) (14.3%). Conclusions Allo-HSCT can be a treatment option to advanced or relapsed/refractory ENKL, but its role still requires more rigorous future studies.