Effect of gastric cancer screening on long-term survival of gastric cancer patients: results of Korean national cancer screening program

Background Gastric cancer (GC) is the most common cancer type in Korea. Korean National Cancer Screening Program (KNCSP) offer either upper gastrointestinal series (UGIS) or upper endoscopy biennially for adults aged ≥ 40. This study aimed to investigate the effect of cancer screening program on the long-term survival among GC patients. Methods A nationwide population-based cohort was constructed based on three national databases. Overall, 46,701 GC patients diagnosed in 2008 and 2009 were included in our final analysis, and they were followed-up until the end of 2019. Survival curves were estimated using the Kaplan–Meier analysis with the log-rank test. Cox proportional-hazards regression analysis was used to report the hazard ratios (HRs) with 95% confidence intervals. Results A total of 18,614/46,701 (39.9%) patients died during the median follow-up time of 10.5 years. The survival rate was higher among screened patients (65.8%) than never-screened patients (49.1%). Screened patients had 53% (HR, 0.47; 95% CI 0.45–0.48) lower risk of death from GC. The HRs of GC-specific mortality was lower in upper endoscopy group (HR = 0.36; 95% CI = 0.34–0.37) compared with UGIS (HR = 0.69; 95% CI = 0.67–0.73). Screened patients within 2 years prior to cancer diagnosis had a 35% reduction in risk of GC death. The figure decline to approximately 19% among patients with interval time since last screening of > 3 years. Conclusions Our findings emphasized the positive effects of GC screening on long-term GC patient survival. Also, patients screened by upper endoscopy or within 2 years before diagnosis had the best survival outcomes.