To Study the Feasibility and Quality of Life of Medial Group Retropharyngeal Node Sparing in Nasopharyngeal Carcinoma

Inclusion Criteria: 1. Patients without medial group retropharyngeal node metastasis; 2. Patients with newly histologically confirmed non-keratinizing (according to WHO histologically type); 3. Tumor staged as T1-4N0-3(according to the 8th AJCC edition); 4. No evidence of distant metastasis (M0); 5. Satisfactory performance status: Karnofsky scale (KPS) ≥ 70; 6. Patients must be informed of the investigational nature of this study and give written informed consent. Exclusion Criteria: 1. Patients with medial group retropharyngeal node metastasis; 2. Aged \> 65 or \< 18; 3. Treatment with palliative intent; 4. Prior malignancy except adequately treated basal cell or squamous cell skin cancer, in situ cervical cancer; 5. Pregnancy or lactation (consider pregnancy test in women of child-bearing age and emphasize effective contraception during the treatment period); 6. With history of previous RT (except for non-melanomatous skin cancers outside intended RT treatment volume); 7. Prior chemotherapy or surgery (except diagnostic) to primary tumor or nodes; 8. Any severe intercurrent disease, which may bring unacceptable risk or affect the compliance of the trial.