Long-Term Outcomes of Definitive Chemoradiotherapy for Early-Stage Extranodal Natural Killer/T-cell Lymphoma, Nasal Type: A Retrospective Analysis From a Single Center.

Background Nasal extranodal natural killer (NK)/T-cell lymphoma (ENKTL) is a rare type of lymphoma with characteristic histological features. Although radiotherapy can achieve a high response rate, long-term efficacy and safety are yet to be established. Methodology Using electronic health records, we identified relevant patients treated at our hospital from August 2005 to August 2015. We enrolled patients with pathologically confirmed ENKTL treated with curative intent radiotherapy. Results We included 13 patients who underwent definitive radiotherapy in the analysis, comprising 11 males and 2 females and a median age of 53 years (range: 28-73). The median follow-up period was 113.4 months. The overall survival at 5 and 10 years was 92.3% (95% confidence interval [CI]: 57-99 %) and 68.4% (95% CI: 29-89 %), respectively. The most common radiation-related late-term toxicity was sinus disorder (Grade 1-2) in 11 patients (85%). Radiation-related grade 3 to 5 toxicities were not observed. Conclusion The present retrospective study elucidated the long-term safety and effectiveness of curative intent radiotherapy in patients with localized ENKTL.