Prophylactic cervical lymph node irradiation provides no benefit for patients of stage IE extranodal natural killer/T cell lymphoma, nasal type.

Radiation therapy (RT) may cure many patients with stage IE extranodal natural killer/T cell lymphoma (ENKTL), but the real benefit of prophylactic cervical node irradiation (PCNI) for this patient population has not been defined yet. We retrospectively reviewed 126 patients who were diagnosed as stage IE ENKTL and treated with chemoradiotherapy in Sun Yat-sen University Cancer Center. The RT dose was 36-72 Gy (median 54 Gy), with 1.8-2.0 Gy a day and 5 fractions each week. 35 patients (27.8 %) in this cohort received PCNI. At a median follow-up time of 94.59 months (range 14.59-182.08 months), the systemic failure rate and locoregional failure rate in patients with PCNI were 76.5 and 23.5 %, respectively, compared with 62.9 and 37.1 % in those without PCNI, and there was no significant difference between those two groups (P = 0.505). Whether patients received PCNI or not did not affect the survival outcome (P > 0.05). Also, PCNI did not improve the survival outcome for neither patients with primary tumor site localized to nasal cavity nor those localized to upper aerodigestive tract beyond nasal cavity (P > 0.05), and PCNI did not provide survival benefit for neither patients with local tumor invasion nor those without (P > 0.05). In conclusion, in a large cohort of 126 patients with stage IE ENKTL, we found that PCNI provided no benefit for PFS and OS, regardless of the primary tumor site or local tumor invasiveness.