Progress in the treatment of NK-cell lymphoma/leukemia

Abstract

Natural killer (NK)/T cell lymphoma includes two major subtypes of disease, specifically extranodal NK/T cell lymphoma, nasal type (ENKL) and aggressive NK cell leukemia (ANKL). Both are strongly associated with Epstein-Barr virus and are prevalent in East Asia and Latin America. Except for that of limited-stage ENKL, the prognosis of both diseases was poor in the previous decade. The advent of non-anthracycline-based chemoradiotherapy has contributed to an improvement in ENKL prognosis, but there is still room for further treatment progress. Recently, the high efficacy of PD-1 antibody was reported in relapsed or refractory ENKL patients. This was later supported by the finding that PD-L1/PD-L2 genetic alterations are frequently observed in ENKL and ANKL patients. Due to the rarity of the disease, a standard treatment for ANKL remains to be established. Currently, allogeneic stem cell transplantation is the only curative treatment, and this is even applicable to chemo-resistant ANKL patients. In this review, we focus on recent treatment approaches for NK/T cell lymphomas including novel agents.