Background
In high-incidence regions, community-based endoscopic screening plays an important role in gastric cancer (GC) prevention and early detection. However, long-term data across the full spectrum of precancerous gastric lesions are limited, hindering the development of community-level risk-stratified screening and surveillance strategies. In particular, it remains unclear which subgroups derive the greatest benefit from intensified or repeat endoscopic screening within community prevention programs.
 
Objectives
To quantify long-term GC incidence and absolute risk across the full spectrum of precancerous gastric lesions in a community-based high-risk population, and to evaluate the incremental benefit of repeat endoscopic screening for early cancer detection, thereby informing risk-stratified community prevention strategies.
 
Methods
We conducted a large multicenter, community-based prospective cohort study including 92,190 adults aged 40-75 years from five high-risk provinces in China (Henan, Hebei, Shandong, Jiangsu, and Sichuan) between 2017 and 2022. All participants underwent baseline endoscopic screening with standardized histopathological classification into seven groups: normal mucosa, non-atrophic gastritis, ulcer/polyp, atrophic gastritis, intestinal metaplasia (IM), low-grade intraepithelial neoplasia (LGIN), and high-grade intraepithelial neoplasia (HGIN). Incident GC cases were ascertained through population-based cancer registries through September 30, 2025. Gastric cancer incidence, cumulative incidence, and 5-year absolute risks were estimated using Cox proportional hazards models and Kaplan-Meier methods. A randomly selected subgroup (n= 1,713) underwent repeat endoscopic screening to assess incremental detection and missed diagnosis rates under a community screening setting.
 
Results
After excluding 1,916 individuals with baseline esophageal HGIN or cancer, 90,274 participants were included (median age 55.6 years; 40.5% male). During a median follow-up of 5.92 years, 527 incident GC cases were identified. GC risk increased markedly with histological severity. Cumulative incidence was 0.31% for normal mucosa, 0.38% for non-atrophic gastritis, 0.34% for ulcer/polyp, 0.53% for atrophic gastritis, 0.49% for IM, 3.05% for LGIN, and 42.20% for HGIN. Corresponding 5-year absolute risks were 0.3%, 0.3%, 0.3%, 0.5%, 0.6%, 2.8%, and 43.0%, respectively. Compared with normal mucosa, multivariable-adjusted hazard ratios for GC were 6.62 (95% CI: 4.75-9.23) for LGIN and 111.41 (95% CI: 87.54-141.78) for HGIN. In the repeat-screening subgroup, the incremental benefit of a second endoscopy was highly concentrated among individuals with advanced precancerous lesions, with reduced missed diagnoses in IM (1.33%), LGIN (1.94%), and HGIN (14.29%). In contrast, missed diagnosis rates among individuals with other non-advanced lesions were negligible (<0.5%).
 
Conclusions
This large community-based cohort demonstrates a pronounced, graded increase in gastric cancer risk across precancerous lesions, with particularly high risk in low- and high-grade intraepithelial neoplasia. Repeat endoscopic screening provided additional detection mainly among advanced lesions, while missed diagnoses were minimal in non-advanced lesions, supporting a risk-stratified approach to community-based early detection.