Abstract: Objective: To investigate the prognostic effect of different scopes and doses of radiotherapy and preventive neck eradiation to nasal NK/T cell lymphoma at early stage. Methods: Analyze the clinical feature of 68 patients with stage I and Ⅱ nasal NK/T cell lymphoma who received radiotherapy in our department from January 1985 to January 2005 in retrospect. According to the different scopes of radiotherapy, the patients can be divided into two groups, one group is involved field with 27 patients, another group is extended field with 41 patients. According to the different radiotherapy doses , the patients can be divided into 4 groups as less 45Gy group with 11 patients，45～50Gy group with 32 patients , 50～60Gy group with 17 patients and more than 60Gy group with 8 patients. 38 patients have received preventive neck eradiation and other 30 haven’t. Kaplan-Meier method was used to calculate the local control rate and 5-year survival rate, Log-rank test was used to inspect the significant difference. Results: The total local control rates and 5-year survival rates are 79.4% and 52.9%. The local control rates of group of involved field radiotherapy and group of extended field radiotherapy are 66.7% and 87.8%, the 5-year survival rates of these two groups are 29.6% and 68.3% (P<0.05). The local control rates of radiotherapy dose less 45Gy group, 45～50Gy group, 50～60Gy group and more than 60Gy group are 45.5%、84.4%、87.5%、88.9%（P＜0.05）, the 5-year survival rates of these groups are 36.4%，56.3%，56.3%，55.6%（P＜0.05）. Analysis on the local control rate and 5-year survival rate of the radiotherapy dose less 45Gy group have significance in statistics and the comparison among other three groups has no significance in statistics（P＞0.05）. The neck lymph node metastasis rate of the patients group who have received preventive neck eradiation and the other patients group who haven’t are 7.9% and 36.7%（P＜0.05）, 5-year survival rates of these two groups are 55.3% and 50.0% (P>0.05). Conclusion: Extended field radiotherapy at early stage has good effect for the local control rate and long term survival rate of the patients with nasal NK/T cell lymphoma. The dose of radiotherapy should be more than 40Gy. Preventive neck eradiation achieved lower neck lymph node metastasis rate but has no effect on the survival.

Key words: Nasal, NK/T cell lymphoma, Radiotherapy, Prognosis