Beneficial effects of endoscopic screening on gastric cancer and its optimal screening interval: a population-based study

Background and study aims: The effectiveness of endoscopic screening on gastric cancer (GC) is less investigated and screening interval of repeated screening is yet to be optimized in China. Patients and methods: In a population-based prospective study, we included 375,800 subjects based on the Upper Gastrointestinal Cancer Early Detection Program in Linqu, a GC high-risk area in China, 14,670 of which underwent endoscopic screening(2012-2018). We assessed the associations of the risk of incident GC and GC-specific deaths with endoscopic screening and examined the changes in overall survival (OS) and disease-specific survival (DSS) of GCs by endoscopic screening. The optimal screening interval of repeated endoscopy for early detection of GC was explored. Results: Ever receiving endoscopic screening significantly decreased the risk of invasive GC(age and sex-adjusted RR=0.69, 95%CI:0.52-0.92) and GC-specific deaths(RR=0.33, 95%CI: 0.20-0.56), particularly for non-cardia GC. Repeated screening strengthened the beneficial effect on invasive GC-specific deaths by one-time screening. Among invasive GCs, screening-detected cases had significantly better OS(RR=0.18, 95%CI: 0.13-0.25) and DSS(RR=0.18, 95%CI: 0.13-0.25) than cases in the unscreened group, particularly for those receiving repeated endoscopy. For individuals with intestinal metaplasia or low-grade intraepithelial neoplasia, repeated endoscopy at an interval of less than two years, particularly within one year, significantly enhanced the detection of early GC, compared with repeated screening after two years(P-trend=0.02). Conclusion: Endoscopic screening prevented GC occurrence and death and improved its prognosis in a population-based study. Repeated endoscopy enhanced the effectiveness, for which screening interval needs to be defined in conformity with the severity of gastric lesions.