Modulation Therapy for Locally Advanced NPC Based on Plasma EBV DNA Level Post-ICT

Inclusion Criteria: 1. Subjects must sign the informed consent form, and must be willing and able to comply with the visits, treatment regimen, laboratory tests and other requirements specified in the study protocol; 2. Age at diagnosis: 18-70 years old; 3. Firstly diagnosed, pathologically confirmed primary nasopharyngeal carcinoma with "non-keratinizing carcinoma (WHO criteria)"; 4. Locally advanced nasopharyngeal carcinoma (T3-4N0-1M0, TanyN2-3M0), staged according to the American Joint Committee on Cancer (AJCC) 8th edition clinical staging system; 5. Pretreatment EBV DNA \>0; 6. ECOG score: 0-1 points; 7. Does not receive any treatment after the diagnosis of nasopharyngeal carcinoma; 8. Normal bone marrow function: white blood cell \>4\*109/L, neutrophil count \>1.5\*109/L, hemoglobin concentration \> 90g/L, platelet count \>100\*109/L; 9. Normal liver and kidney function: total bilirubin ≤1.5 times the upper limit of normal; aspartate aminotransferase and/or alanine aminotransferase ≤ 2.5 times the upper limit of normal; creatinine clearance ≥ 60mL/min; 10. For those with hepatitis B infection, the HBV DNA load must be \< 2500 copies/ml at the time of screening; For those with anti-hepatitis C virus antibody, HCV RNA must be negative at the time of screening; 11. Female subjects of childbearing potential and male subjects with partners of childbearing potential must agree to use reliable contraception (e.g. condoms, regular contraceptives as directed) from screening through 1 year after treatment. Exclusion Criteria: 1. Pathologically confirmed primary nasopharyngeal carcinoma with "keratinizing carcinoma or basaloid squamous cell carcinoma"; 2. Previous or current other malignancy other than adequately treated non-melanoma skin cancer, carcinoma in situ of the cervix, and papillary thyroid carcinoma; 3. Pretreatment plasma EBV DNA undetectable; 4. History of radiation therapy prior to standard therapy (except for non-melanoma skin cancer, and the previous radiation field did not overlap with the current treatment for nasopharyngeal carcinoma); 5. Patients who received surgical treatment (except for diagnostic biopsy), biological therapy, chemotherapy or immunotherapy before enrollment; 6. Conditions mentioned below: 1) Currently enrolled in other interventional clinical trial; 2) Systemic hormonal or other immunosuppressive therapy with an equivalent dose of \> 10mg prednisone/day within 28 days prior to informed consent; 3) Receipt of live vaccines within 30 days prior to enrollment; 4) Surgery or trauma within 30 days prior to enrollment; 7. Uncontrolled heart disease, such as :1) heart failure, NYHA ≥ 2; 2) unstable angina; 3) history of myocardial infarction within 1 year; 4) supraventricular or ventricular arrhythmia requiring treatment or intervention; 8. History of stroke within 6 months; 9. Patients with severe active infection within 30 days prior to enrollment, that must be treated with systemic antibacterial, antifungal or antiviral therapy; 10. Active autoimmune disease (including but not limited to uveitis, enteritis, hepatitis, pituitary disease, nephritis, vasculitis, hyperthyroidism, etc.). Except for type I diabetes, hypothyroidism requiring hormone replacement therapy, and vitiligo not requiring systemic treatment, inactive childhood asthma that does not require treatment as an adult; 11. Positive anti-HIV antibody or diagnosis of other innate or acquired immunodeficient, immunosuppressive disease, history of organ transplantation; 12. Interstitial lung disease or pneumonia requiring oral or intravenous steroid therapy within 1 year; 13. Active tuberculosis infection, or previous lung tuberculosis infection within 1 year, or previous lung tuberculosis infection more than 1 year prior to enrollment but did not receive standard anti-tuberculosis treatment; 14. Positive hepatitis B surface antigen and hepatitis B virus DNA ≥ 2500 copies/ml or Positive hepatitis C RNA; 15. Pregnant or lactating women (pregnancy test should be considered for sexually active women of childbearing age); 16. Other conditions that may jeopardize patient safety or compliance as assessed by investigator, such as serious illness (including psychiatric disorders) requiring prompt treatment, severely abnormal test results, and other family or social risk factors.