Purpose: Extranodal natural killer/T-cell lymphoma (ENKTL), nasal-type, is a distinct subtype of non-Hodgkin lymphoma. ENKTL is sensitive to radiotherapy, but the prognosis is poorer than those of other types of early stage lymphoma. To date, optimal treatment strategies for patients with early stage ENKTL have not been fully defined. Methods: We retrospectively investigated the efficacy and safety of pegaspargase, gemcitabine, and oxaliplatin (P-GEMOX) combined with different dose radiotherapy (RT) in the treatment of 35 newly diagnosed, stage IE to IIE ENKTL patients at our institution from October 2011 to September 2015. All patients were treated with RT (< 54 Gy or >= 54 Gy) after an initial two cycles of P-GEMOX, and following two consolidation cycles. The primary endpoints were objective response rate and complete remission rate (CR). The secondary endpoints were 2-year overall survival (OS), 2-year progression-free survival (PFS), and toxicity. Results: Thirty-three patients completed total therapy, which resulted in 94.3% of response rate that included 28 patients (80.0%) with CR and five patients (14.3%) with partial response (PR). Two (5.7%) patients progressed during therapy and six (17.1%) progressed during follow-up. The 2-year OS was 82.9%, and the 2-year PFS was 77.1%. Patients with CR, low circulating EBV DNA load (<= 6.1 x 10(7) copies/ml), low NKIPI (score 0-1), and high RT dose (>= 54 Gy) were independent predictors of better prognosis. Grade 3 toxicities were few; only four (11.4%) patients experienced grade 4 toxicities. No treatment-related deaths were observed. Conclusions: The research showed that the treatment of P-GEMOX combined with RT was a tolerable and effective treatment for localized nasal natural killer/T-cell lymphoma.