Review: Prevention and management of gastric cancer.

Gastric cancer (GC) is still the fifth most frequently diagnosed cancer and the third leading cause of cancer deaths in both sexes worldwide. Although the incidence of GC is predicted to continue declining in a growing number of countries in the future, on a global scale the number of newly diagnosed GC cases will remain high, or increase even further, due to changes in population size and increasing risks observed in younger generations. In a retrospective cohort study, collecting data from the Veterans Health Administration, treatment of Helicobacter pylori infection decreased GC risk only if eradication was successful. In a German case-control study, among GC patients with autoimmune gastritis, pernicious anemia was associated with earlier detection of GC, which translated into a significantly better 5-year survival. In an updated meta-analysis, H. pylori eradication therapy in healthy individuals significantly reduced both GC incidence and mortality from GC with a number needed to treat of 72 and 135, respectively. In Korea, successful H. pylori eradication substantially reduced GC incidence in first-degree relatives of GC patients as well. A meta-analysis of four trials including 1,556 patients with resectable GC reported that the patient subgroup tumors with high microsatellite instability undergoing surgery did not benefit from perioperative or adjuvant chemotherapy.