Comparison and Strategy Optimization of Plasma EBV DNA and P85-Ab with VCA/EBNA1-IgA for Screening Nasopharyngeal Carcinoma in High-risk Areas

This study is a prospective, self-controlled, multicenter clinical trial. All participants will be tested for Epstein-Barr virus (EBV) associated biomarkers, including the two-antibody method (VCA-IgA and EBNA1-IgA), BNLF2b total antibodies (P85-Ab), and plasma EBV DNA. Furthermore, novel screening biomarkers, such as next-generation sequencing for EBV and castoff cells using nasopharyngeal swabs, will be explored. First, it aims to investigate whether plasma EBV DNA testing or the P85-Ab testing can achieve higher sensitivity than the current standard two-antibody method testing while maintaining specificity in NPC screening, thereby identifying the optimal initial NPC screening strategy. Based on the determined optimal initial screening strategy, the study will validate the proposed two-step method (subjects first undergo two-antibody method testing and P85-Ab testing; those positive for either one biomarker above proceed to plasma EBV DNA testing; subjects positive in both steps are defined as high-risk and receive endoscopic examinations with or without biopsy) compared with the single-step method (subjects simultaneously undergo two-antibody method testing, P85-Ab testing, and plasma EBV DNA testing; subjects with any positive biomarker undergo endoscopic examinations with or without biopsy) and each single screening testing. The aim is to determine whether two-step method can further improve the positive predictive value (PPV) while maintaining non-inferior sensitivity, thereby enhancing screening efficiency, reducing the rate of invasive procedures (such as endoscopic biopsies), and lowering medical costs and insurance burdens.