Radiotherapy Alone Versus Concurrent Chemo-radiotherapy for Nasopharyngeal Carcincoma Patients With Undectable EBV DNA After One Cylce Neoadjuvant Chemotherpy

The goal of this multicenter randomized non-inferior study is to compare radiotherapy alone versus concurrent chemoradiotherapy in locally advanced nasopharyngeal carcinoma patients whose EBV DNA drop to undetectable level after one cycle neoadjuvant chemotherapy using GP regimen. The main question it aims to answer is: the omission of concurrent chemotherapy is safe in the relatively good prognostic patients identified by the response of EBV DNA. Participants will be randomized to either radiotherapy alone or the standard treatment concurrent chemoradiotherapy if their EBV DNA decrease to undetectable level post first cycle of neoadjuvant chemotherapy and don't rebound in the second and third cycle.