The Roles of Radiotherapy and Chemotherapy in the Era of Multimodal Treatment for Early-Stage Nasal-Type Extranodal Natural Killer/T-Cell Lymphoma

PURPOSE To evaluate radiotherapy (RT) and chemotherapy (CT) treatments of early-stage extranodal natural killer/T-cell lymphoma (ENKTL). MATERIALS AND METHODS Fifty-five patients with stage I or II ENKTL [n=39 (71%) and 16 (29%) patients, respectively] who were treated with RT between 1999 and 2013 were analyzed retrospectively. The median age was 54 years (range, 24-81). Patients were grouped by treatment modality as RT alone [n=19 (35%)], upfront CT plus RT [CT+RT, n=16 (29%)], and concurrent chemoradiotherapy [CCRT, n=20 (36%)]. The median RT dose was 48 Gy. Patient characteristics between each treatment group were well balanced. Patterns of failure and survival were analyzed. RESULTS The overall response rate after RT was 94.6%. Ten patients experienced distant failure, and seven experienced local failure comprising five in-field and two out-field failures. The local and distant failure rates in the RT-alone group were the same (16%). In the CT+RT group, the most common failure sites were local (19%). In the CCRT group, the most common failures were distant (25%). At a median follow-up of 56 months (range, 1-178 months), the 5-year overall survival (OS) and progression-free survival rates were 66% and 54%, respectively. The 5-year OS rate for the RT-alone and CT+RT groups were 76% and 69%, respectively, and the 2-year OS rate for the CCRT group was 62% (p=0.388). CONCLUSION In the era of multimodal treatment for ENKTL, RT alone using advanced techniques should be considered for local disease control, whereas maintenance CT regimens should be considered for distant disease control.