Effects of Helicobacter Pylori on Gastric Cancer in the Adult Population: A Systematic Review

Abstract

Gastric cancer is a cancer that leads to high mortality worldwide. Helicobacter pylori (H. pylori) infection is a major risk factor for gastric cancer. This review covers non-cardia and cardia gastric adenocarcinomas (both clinically and histopathologically confirmed) according to the included studies. Early detection and eradication therapy has been proposed in order to reduce incidence and mortality. This systematic review was conducted according to PRISMA 2020 guidelines. Searches from January 2020 to July 2025 identified 32 eligible studies. These included four randomized controlled trials, one quasi-experimental study, three systematic reviews with meta-analysis, and 24 observational studies. Most were conducted in East Asia and Latin America. Eradication therapy was associated with a 40–55% reduction in the occurrence of gastric cancer, particularly in precancerous stages such as intestinal metaplasia or early carcinoma. A residual risk persisted, likely due to chronic inflammation, microbiome changes, or genetic predisposition. Early diagnosis and eradication of H. pylori can reduce the risk of gastric cancer, particularly in high-risk regions. Combining eradication therapy with surveillance and microbiome restoration programs may provide the greatest benefit at a national level.