In recent years, asparaginase-based chemotherapy regimens have produced excellent short-term efficacy in patients with extranodal natural killer/T-cell lymphoma (ENKTL). However, few long-term outcomes have been reported to date. A phase II clinical trial evaluating the efficacy and safety of a combination of gemcitabine, oxaliplatin and asparaginase (GELOX), followed by radiotherapy (RT) in the treatment of localized ENKTL, was reported by this group in 2012. By the time of the present analysis, detailed information had been collected for all 27 patients in the phase II trial, over an extended follow-up period. The median follow-up time was 63.15 months. The 5-year overall survival and progression-free survival were 85.0 and 74.0%, respectively. Recurrence within the RT field was observed in three patients, and the planning target-volume control rate at 5 years was 88.9%. One patient with confirmed lung invasion who did not respond to autologus stem cell transplantation (ASCT) was successfully treated by salvage therapy with lenalidomide monotherapy, and the EBV DNA load in this individual reflected disease progression and treatment response. No clinically significant late toxicities were identified during follow-up visits. In conclusion, this updated analysis confirmed the long-term benefit of the GELOX regimen followed by RT, and demonstrated a good safety profile for this treatment. This strategy may be one of the most suitable options for the treatment of early stage ENKTL.