 Post-operative radiotherapy: Radiotherapy was arranged 4 to 6 weeks after surgery. Routine external beam radiotherapy, such as conformal or intensity modulated radiotherapy was performed, and the dose was 1.8-2 Gyday, 5 daysweek for 6 weeks, and totally 54-60 Gy, in the patient with high risk features, such as positive surgical margin, extra capsular nodal spread, vascular embolism, concurrent chemotherapy with cisplatin 80mgm2 was suggested. 