Evaluation of the Sensitivity of Endoscopy to Detect Nasopharyngeal Carcinoma (NPC) in an Epstein-Barr Virus (EBV)-Based NPC Screening Project in China

Epstein-Barr virus (EBV) is a necessary cause of nasopharyngeal carcinoma (NPC). Individuals who develop NPC have been shown to have an altered EBV antibody profile. Ongoing efforts to evaluate EBV antibody testing as a screening test for the early detection of NPC have been launched in China and Taiwan but it is unclear whether the current method to detect NPC among screen-positive individuals (i.e., visual inspection with the aide of an endoscope) is sufficiently sensitive to detect prevalent cancers among screen positive individuals. In the present study, we aim to evaluate the sensitivity of endoscopy to detect NPC. The study is embedded within a large, community-based trial in China to evaluate EBV antibody testing as a screening test that triages individuals into endoscopy for the early detection of NPC. We plan to enroll 1,000 individuals with elevated EBV antibody scores within the active screening arm of the trial in China. Participants will have both endoscopy and MRI performed to detect nasopharyngeal lesions. Lesions identified by either method will be biopsied and evaluated for the presence of NPC. NPC cases will also be identified by linkage to the regional cancer registry. We expect to identify a total of 25 histologically confirmed NPC cases through endoscopy, MRI and/or registry linkage. The sensitivity of endoscopy to detect prevalent NPC will be estimated. Characteristics of prevalent NPC cases detected by MRI or registry linkage but missed by endoscopy will be described, with respect to clinical stage, socio-demographic and other characteristics. This study is an important complement to the ongoing screening trial in China, as a highly sensitive EBV-based screening test can ultimately be successful only if methods available to identify cancer among screen-positive individuals are equally sensitive. Demonstration of high sensitivity of endoscopy to detect NPC will be reassuring. Demonstration of reduced sensitivity will trigger the need to consider alternatives to endoscopy for the diagnosis of NPC.