Metronomic Capecitabine With or Without PD-1 Antibody as Adjuvant Therapy in High-risk Nasopharyngeal Carcinoma

Inclusion Criteria:

1. Age at diagnosis: 18 ~ 65 years old;
2. Pathologically confirmed primary nasopharyngeal carcinoma with "non-keratinizingcarcinoma (WHO criteria)";
3. Locoregionally advanced nasopharyngeal carcinoma (T4N + or TanyN2-3M0, or TanyNanyM0pretreatment EBVDNA ≥ 4000 copies/mL) was diagnosed according to the American JointCommittee on Cancer/Union for International Cancer Control (AJCC/UICC) 8th editionclinical staging system.
4. Induction and concurrent chemoradiotherapy with the recommended regimen have beencompleted;
5. ECOG score: 0 ~ 1 points (Appendix II);
6. It is recommended to initiate adjuvant therapy within 1 month after the completion ofthe last radiotherapy treatment, no later than 6 weeks;
7. Normal bone marrow function: white blood cell count > 4 × 109/L, hemoglobinconcentration > 90 g/L, platelet count > 100 × 109/L;
8. Normal liver and kidney function: total bilirubin ≤ 1.5 times the upper limit ofnormal; aspartate aminotransferase and/or alanine aminotransferase ≤ 2.5 times theupper limit of normal; alkaline phosphatase ≤ 2.5 times the upper limit of normal;creatinine clearance ≥ 60 mL/min;
9. Subjects must sign the informed consent form, and must be willing and able to complywith the visits, treatment regimen, laboratory tests and other requirements specifiedin the study protocol;
10. Female subjects of childbearing potential and male subjects with partners ofchildbearing potential must agree to use reliable contraception (e.g., condoms,regular contraceptives as directed) from screening through 1 year after treatment.

Exclusion Criteria:

1. Positive hepatitis B surface antigen and hepatitis B virus quantification > 1 × 1000copies/ml, or positive anti-hepatitis C virus antibody;
2. Positive anti-HIV antibody or diagnosis of acquired immunodeficiency syndrome (i.e.,AIDS);
3. Conditions such as dysphagia, chronic diarrhea, or bowel obstruction that wouldinterfere with oral medication.
4. Patients with severe chronic or active infection that must be treated with systemicantibacterial, antifungal or antiviral therapy before randomization, including but notlimited to tuberculosis infection
5. Active, known or suspected autoimmune disease (including but not limited to uveitis,enteritis, hepatitis, pituitary disease, nephritis, vasculitis, hyperthyroidism,hypothyroidism, and asthma requiring bronchiectasis). Except for type I diabetes,hypothyroidism requiring hormone replacement therapy and skin diseases not requiringsystemic treatment (such as vitiligo, psoriasis or alopecia); clinicians shouldperform necessary history, examination and examination before enrollment for the abovediseases and then exclude them;
6. Interstitial lung disease or pneumonia requiring oral or intravenous steroid therapywithin 1 year;
7. Definite clinical evidence of persistent local disease or distant metastasis afterchemoradiotherapy;
8. Systemic hormonal or other immunosuppressive therapy with an equivalent dose of > 10mg prednisone/day within 28 days prior to informed consent. Subjects with systemic sexhormone doses ≤ 10 mg prednisone/day or inhaled/topical corticosteroids may beincluded.
9. Uncontrolled heart disease, such as: 1) heart failure, NYHA level ≥ 2; 2) unstableangina; 3) history of myocardial infarction in the past year; 4) supraventriculararrhythmia or ventricular arrhythmia requiring treatment or intervention;
10. Pregnant or lactating women (pregnancy test should be considered for sexually activewomen of childbearing age);
11. Previous or current other malignancy other than adequately treated non-melanoma skincancer, carcinoma in situ of the cervix, and papillary thyroid carcinoma;
12. Receipt of live vaccines within 30 days prior to the first course of tislelizumab;
13. History of organ transplantation;
14. Other conditions that may jeopardize patient safety or compliance as assessed by theinvestigator, such as serious illness (including psychiatric disorders) requiringprompt treatment, severely abnormal test results, and other family or social riskfactors.
15. Patients who received surgical treatment, biological therapy, or immunotherapy duringor before radiotherapy;
16. Patients who are receiving or are likely to receive other chemotherapy, biologicaltherapy, or immunotherapy History of severe hypersensitivity to other monoclonalantibodies;
17. Chemotherapy or surgery (except diagnostic) of the primary tumor or lymph nodes beforestandard treatment.
18. History of radiation therapy prior to standard therapy (except for non-melanoma skincancer).
19. Patients who are known to be intolerable or sensitive to any therapeutic agents.