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

This study is testing whether adding a PD-1 immunotherapy drug to metronomic capecitabine (low-dose oral chemotherapy given continuously) after chemoradiotherapy reduces the risk of nasopharyngeal carcinoma (a throat cancer) coming back in high-risk patients. **You may be eligible if...** - You are between 18 and 65 years old - You have been diagnosed with high-risk, locally advanced nasopharyngeal carcinoma (non-keratinizing type) - You have already completed induction and concurrent chemoradiotherapy - You plan to start adjuvant therapy within 1–6 weeks of finishing radiotherapy - Your blood counts and organ function are normal - Your ECOG score is 0 or 1 **You may NOT be eligible if...** - You have not completed the required chemoradiotherapy - Your blood counts or organ function do not meet required levels - Your cancer has metastasized to distant organs Talk to your doctor to see if this trial is right for you.