Appropriate Extent for Elective Irradiation to the Neck of N_0 Nasopharyngeal Cancer Patients

Objective To justify the elective irradiation volume of the neck in N 0 nasopharyngeal cancer (NPC) patients. Methods One hundred and ninety six NPC patients without overt neck node metastases were retrospectively analyzed. All patients were treated with radiotherapy alone and followed up beyond 5 years. The extent of elective neck irradiation defined at upper half of the neck. Median radiation doses were 70Gy in the primary tumors and 50Gy (40～72)Gy in the upper necks. Results Nine out 196 patients wer...