Effectiveness of endoscopic gastric cancer screening in a rural area of Linzhou, China: results from a case-control study

In China, a large burden of gastric cancer has remained, and endoscopic screening was expected to reduce gastric cancer mortality. Therefore, a population-based case-control study was conducted to evaluate the screening effect. The gastric cancer screening program was initiated in Linzhou in the year 2005, and endoscopic examination with indicative biopsy, for residents aged 40-69 years, was used to detect early cancer and precancerous lesion. In this study, cases were defined as individuals who had died of gastric cancer, which were selected from Linzhou Cancer Registry database. Controls were residents (six per case), who had not died of gastric cancer, from the same area as the case, and matched by gender and age (+/- 2 years). The exposure status, whether cases and controls ever attended the screening or not, was acquired by inspecting the well-documented screening records. Conditional logistic regression model was used to estimate the odds ratios (OR) and their 95% confidence intervals (95% CI). A total of 313 cases and 1876 controls were included in our analysis. Compared with subjects who never participated in screening, the overall OR for individuals who ever participated in screening was 0.72 (95% CI: 0.54-0.97). The OR for lag time 4years or longer was 0.68 (95% CI: 0.47-0.98) and the OR for those who were aged 50-59 years were 0.56 (0.37-0.85). The results suggest a 28% reduction in risk of gastric cancer mortality by endoscopic screening, which may have significant implications for gastric cancer screening in rural areas of China.