This study is a single-arm, open-label, prospective, and exploratory investigation aimed at examining the short-term efficacy, specifically the objective response rate (ORR), of SBRT combined with Nimotuzumab followed by Tislelizumab in patients with recurrent/metastatic nasopharyngeal carcinoma who have experienced oligoprogression (1-5 metastatic lesions) after immunotherapy.

1. Inclusion Criteria:

   1.1. Pathologically confirmed non-keratinizing nasopharyngeal carcinoma; 1.2. Patients with recurrent/metastatic nasopharyngeal carcinoma who have previously received first-line treatment including anti-PD-1 immune checkpoint inhibitor therapy and failed, presenting with oligoprogression (1-5 metastatic lesions); 1.3. Eligible to receive SBRT, Tislelizumab, and Nimotuzumab; 1.4. No history of other malignant tumors; 1.5. Male or female, aged 18-75 years; 1.6. Liver function: Total bilirubin ≤ Upper Limit of Normal (ULN); AST and ALT ≤ 2.5 × ULN; Alkaline phosphatase ≤ 5 × ULN; 1.7. Renal function: Creatinine clearance ≥ 80 mL/min; 1.8. Hematological tests: Absolute neutrophil count (ANC) ≥ 2 × 109/L, platelet count ≥ 100 × 109/L, and hemoglobin ≥ 9 g/dL; 1.9. No severe dysfunction of heart, lung, and other vital organs; 1.10. Performance Status (PS) score ≤ 2.

2. Exclusion Criteria:

2.1. Disagree to sign the informed consent form; 2.2. Patients who cannot comply with regular follow-ups due to psychological, social, family, or geographical reasons; 2.3. Receiving other experimental treatments as part of a clinical study (during the treatment period of the clinical study); 2.4. Severe, uncontrolled infections or medical conditions; 2.5. Major organ dysfunction, decompensated heart, lung, kidney, or liver failure, unable to tolerate radiotherapy or immunotherapy; 2.6. Factors affecting drug administration, distribution, metabolism, or excretion, such as mental abnormalities, central nervous system abnormalities, chronic diarrhea, ascites, pleural effusion, etc.; 2.7. Overexposure to glucocorticoids within 2 weeks before immunotherapy; 2.8. Long-term use of immunosuppressive agents after organ transplantation.