Effectiveness evaluation of organized screening for esophageal cancer: a case-control study in Linzhou city, China.

In China, esophageal cancer has remained a large burden, and endoscopic screening is expected to reduce esophageal cancer mortality. Therefore, a population-based case-control study was conducted to evaluate the effect of screening. Cases were defined as individuals who had died of esophageal cancer, and controls were residents from the same area (three per case) who had not died of esophageal cancer, matched by gender and birth year. The exposure status (whether cases and controls had ever attended the screening or not) was acquired by inspecting the well documented screening records. A conditional logistic regression model was used to estimate the odds ratios (OR) and their 95% confidence intervals (95% CI). There were 253 cases and 759 controls. The reduction in risk of esophageal cancer mortality in individuals who had ever attended screening was 47% (OR: 0.53, 95% CI: 0.37-0.77). Compared with never-screened subjects, the ORs for screened subjects within 36 and 48 months before the reference date were 0.59(0.39-0.89) and 0.59(0.40-0.87); the ORs for 50-59 year old subjects were 0.48(0.28-0.85). The results suggest a 47% reduction in esophageal cancer mortality risk due to endoscopic screening, which may have significant implications for esophageal cancer screening in China, especially in rural areas.