Association of the interval between endoscopies with gastric cancer stage at diagnosis in a region of high prevalence

BACKGROUND: Endoscopy screening in high-risk populations may reduce gastric cancer mortality by detecting cancer earlier. We evaluated the association between the interval between upper gastrointestinal endoscopies and the gastric cancer stage at diagnosis in patients from a region of high prevalence. METHODS: The study cohort consisted of 2485 patients diagnosed with gastric adenocarcinoma. We evaluated the effect on cancer stage of the interval between the endoscopy that was diagnostic for gastric cancer and the endoscopy preceding it. Patients were stratified into 7 groups: 1-, 2-, 3-, 4-, 5-, >5-year intervals and those who were never screened. RESULTS: The risk of higher cancer stage at diagnosis increased by 23% per increase in interval length (odds ratio = 1.23, 95% confidence interval [CI] = 1.19-1.28). Compared to the never-screened, the odds ratio of having a higher stage of cancer decreased gradually from 0.53 (95% CI = 0.41-0.69) in the >5-year interval group to 0.31 (95% CI = 0.24-0.40) in the 1-year interval group. Compared to the 1-year interval group, the risk of advanced gastric cancer was increased in the 4- and 5-year, but not the 2- and 3-year, interval groups. However, patients with a family history of gastric cancer were more likely to have a higher stage at diagnosis if they had a 3-year interval rather than a 1-year interval. CONCLUSIONS: A significant benefit in cancer stage at diagnosis was observed in all interval groups compared to never-screened. Endoscopy intervals of 3 years or less showed similar benefits, but family members of gastric cancer patients may benefit from intervals of under 3 years.