Radical Radiotherapy and Chemotherapy Combined With Maintenance Chemotherapy in the Treatment of Stage N3 NPC

Inclusion Criteria: 1. Pathologic diagnosis (pathologically confirmed by nasopharyngeal biopsy) was nasopharyngeal carcinoma; 2. No distant metastatic stage N3 nasopharyngeal carcinoma was first diagnosed (according to the 8th edition UICC/AJCC nasopharyngeal carcinoma staging system defined as any T and N3M0 stage nasopharyngeal carcinoma). 3. Aged 18-65; 4. At least one measurable tumor lesion; 5. PS (ECOG standard) 0-1; 6. Adequate hematopoietic function: WBC≥3.5×109/L, Hb≥100g/L, PLT≥100×109/L; 7. Normal liver and kidney functions: ALT/AST \< 2.5 times the upper limit of normal value (ULN), total bilirubin \< 1.5×ULN;Serum creatinine \< 1.5×ULN; 8. Expected survival period ≥6 months; 9. Signing informed consent; 10. Follow up regularly and comply with test requirements. Exclusion Criteria: 1. Patients with distant organ metastasis; 2. Recurrent nasopharyngeal carcinoma; 3. Creatinine clearance rate \<60ml/ min; 4. Have received chemotherapy, radiotherapy or targeted therapy; 5. Have or are suffering from other malignant tumors within 5 years (except non-melanoma skin cancer or pre-invasive cervical cancer); 6. Serious complications, such as uncontrolled hypertension, coronary heart disease, diabetes, heart failure, etc. 7. Active systemic infection; 8. History of serious lung or heart disease; 9. Drug or alcohol abuse; 10. No or limited capacity for civil conduct; 11. The patient has a physical or mental disorder, and the researcher considers that the patient is unable to fully or fully understand the possible complications of this study; 12. Receive chronic systemic immunotherapy or hormone therapy outside the study; 13. Pregnancy or lactation period; 14. Patients receive blind treatment in other clinical studies.