The goal of this phase I clinical trial is to learn whether a multimodal follow-up evaluation combined with endoscopic selective neck dissection (ESND) is safe and feasible in patients with newly diagnosed N3 nasopharyngeal carcinoma.
The main questions it aims to answer are:
* Is the multimodal evaluation-guided surveillance-intervention approach safe for patients?
* Is this approach feasible for identifying and managing residual cervical lymph nodes after radiotherapy? Participants will receive standard chemoradiotherapy. After treatment, they will undergo follow-up evaluation using clinical assessment, conventional imaging, Epstein-Barr virus DNA testing, and contrast-enhanced ultrasound. Participants with clinically suspicious residual cervical lymph nodes identified by multimodal evaluation and eligible for surgery underwent endoscopic selective neck dissection.