RAIRI Model-Guided Adjuvant Therapy in Nasopharyngeal Carcinoma

Inclusion Criteria 1. Age 18-65 years, regardless of sex. 2. Histologically confirmed EBER-positive, non-metastatic, non-keratinizing nasopharyngeal carcinoma. 3. AJCC 9th edition stage II-III disease / AJCC 8th edition stage III-IVA disease, excluding T3-T4N0 and T3N1 disease; or baseline EBV DNA \>4,000 copies/mL. 4. Eastern Cooperative Oncology Group performance status score of 0-1. 5. Availability of complete baseline pretreatment imaging data, including nasopharyngeal and neck MRI with functional MRI sequences, and at least one measurable tumor lesion. 6. Availability of pretreatment baseline plasma cfEBV-DNA measurement. 7. Patients must meet the following laboratory criteria: hemoglobin \>120 g/L and white blood cell count ≥4 × 10⁹/L. 8. Platelet count ≥100 × 10⁹/L; liver and renal function parameters within 1.25 times the upper limit of normal; and no hearing impairment. 9. Ability to understand the study and provision of written informed consent. 10. Agreement to allow the use of personal data and biological samples, including blood and tissue samples, for research purposes. 11. Adequate function of major organs, except for abnormalities related to nasopharyngeal carcinoma. 12. Ability and willingness to comply with scheduled follow-up. Exclusion Criteria 1. Absence of pretreatment cfEBV-DNA data or other essential baseline characteristic data. 2. AJCC 8th edition stage I-II or IVB disease / AJCC 9th edition stage I or IV disease, or T3-4N0 or T3N1 disease. 3. History of other malignancies, except stage I non-melanoma skin cancer or carcinoma in situ of the cervix. 4. Pregnant or lactating women, or women of childbearing potential who are not using contraception. 5. Current participation in another investigational drug trial. 6. Severe comorbidities, including myocardial infarction, severe arrhythmia, severe cerebrovascular disease, active ulcer disease, psychiatric illness, uncontrolled diabetes mellitus, active autoimmune disease, ongoing systemic immunosuppressive therapy, active infection requiring systemic treatment, history of human immunodeficiency virus infection, positive hepatitis B surface antigen, hepatitis B virus DNA \>1 × 10³ copies/mL or \>200 IU/mL, or positive hepatitis C virus antibody. 7. Inability to comply with regular follow-up.