The Influence of Gastric Cancer Screening on the Stage at Diagnosis and Survival: A Meta-Analysis of Comparative Studies in the Far East.

Gastric cancer is the fifth most common cancer and the second most common cause of cancer-related death worldwide. The aim of this review was to evaluate the effect of gastric cancer screening on the stage at diagnosis and survival from disease. A systematic review of the literature between January 1995 and December 2014 was performed. Studies that compared screened versus nonscreened populations for the diagnosis of gastric cancer and included the stage at diagnosis were analyzed. The QUADAS-2 and the ROBANS tools were used to assess the quality of the studies. A total of 11 studies from the Far East comprising 4039 participants in the screened and 6635 in the nonscreened groups were included. Screening was associated with a significant increase in the detection of early gastric cancer (EGC) [pooled odds ratio (POR)=3.90; 95% confidence interval (CI), 3.01-5.06; P<0.0001] and reduction in the incidence of advanced gastric cancer (POR=0.27; 95% CI, 0.20-0.35; P<0.0001). Furthermore, screening improved the 5-year survival significantly (hazard ratio=0.56; 95% CI, 0.48-0.66; P<0.0001). About 73% of the screened patients were found to have EGC compared with 43% of the nonscreened patients. About 8% of the screened patients were found to have advanced gastric cancer compared with 54% of the nonscreened patients. Screening for gastric cancer is useful in detecting asymptomatic patients with EGC in high-prevalence areas. This in turn increases the number of treatable cancers and improves the 5-year survival. There is a need for the development and the validation of alternative risk-stratification tools in low-incidence areas to allow for similar benefits.