To evaluate the safety and efficacy of PD-1 immune checkpoint inhibitor combined with intensity modulated radiation therapy in the treatment of intermediate-risk nasopharyngeal carcinoma (T2-3N0 or T1-2N1 stage and EBV-DNA≤4000 copy/ml).

To evaluate the safety and efficacy of PD-1 immune checkpoint inhibitor combined with intensity modulated radiation therapy in the treatment of intermediate-risk nasopharyngeal carcinoma (T2-3N0 or T1-2N1 stage and EBV-DNA≤4000 copy/ml).The primary end point is safety, the secondary end points are short-term efficacy,overall survival (OS), progression-free survival (PFS),Distant metastasis-free survival(DMFS),adverse effects ,quality of life and immune status assessment.

Inclusion Criteria:

• Newly diagnosed patients who have not received radiotherapy or chemotherapy
• Pathologically diagnosed as non-keratinizing nasopharyngeal carcinoma (differentiated or undifferentiated, WHO classification type II or type III).
• T2-3N0 or T1-2N1 stage and EBV-DNA≤4000 copy/ml (AJCC 8th version) and EBV-DNA≤4000copies/ml
• Male or non-pregnant female
• Age between 18 and 65
• Eastern Cooperative Oncology Group（ECOG）score of 0-1.
• Hemoglobin (HGB) ≥90 g/L, white blood cell (WBC) ≥4×109/L, platelet (PLT) ≥100×109/L.
• Liver function: Alanine aminotransferase (ALT), aspartate aminotransferase (AST) <2.0 times the upper limit of normal (ULN); total bilirubin <2.0×ULN.
• Renal function: creatinine clearance rate ≥60ml/min or serum creatinine <1.5×ULN.
• The patient has signed the informed consent

Exclusion Criteria:

• The pathology is keratinizing squamous cell carcinoma (WHO classification is type I).
• Patients with recurrence and distant metastasis.
• Patients who have undergone radiotherapy or chemotherapy.
• Active hepatitis B (HBV-DNA≥500).
• Patients with autoimmune diseases.
• Patients with HIV infection.
• At the same time suffering from other uncontrolled serious diseases.
• Persons with abnormal functions of the heart, brain, lungs and other important organs.
• Age> 65 years.
• pregnancy or breast feeding.
• Persons with personality or mental illness, without or with limited capacity for civil conduct