PD-1 Combined With Intensity Modulated Radiation Therapy in the Treatment of Intermediate-risk Nasopharyngeal Carcinoma

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