Tislelizumab Combined With Capecitabine for Nasopharyngeal Carcinoma With Residual EBV DNA After Radiotherapy

This study is testing whether adding an immunotherapy drug (tislelizumab) and an oral chemotherapy (capecitabine) can eliminate residual cancer in people with nasopharyngeal carcinoma (a type of cancer at the back of the nose and throat) who still have detectable Epstein-Barr virus (EBV) DNA in their blood after completing radiation therapy. **You may be eligible if...** - You are 18 or older with a confirmed diagnosis of nasopharyngeal carcinoma - You have already completed radiation therapy (with or without chemotherapy) - After radiation, your blood still shows detectable EBV DNA - Your blood counts, liver, kidney, and heart function are in adequate range **You may NOT be eligible if...** - You have a specific cancer subtype called keratinizing squamous cell carcinoma (WHO type I) - Your cancer has spread to distant parts of the body - You have active autoimmune disease, active tuberculosis, hepatitis B or C, or HIV - You have significant heart disease - You are pregnant or unwilling to use contraception Talk to your doctor to see if this trial is right for you.