Gastric Cancer: Global Epidemiology, Risk Factors, Helicobacter pylori Eradication, and Risk-Based Screening

Background: Declining age standardized rates conceal differences in gastric cancer by age, sex, anatomical subsite, histological type, and region. This review examines these patterns alongside risk factors, Helicobacter pylori eradication, screening, and surveillance. Methods: PubMed, Web of Science, and Scopus were searched iteratively for literature available through January 2026. Google Scholar and reference lists were used to identify additional relevant sources. One reviewer selected sources, and findings were interpreted qualitatively according to study design, population, confounding, precision, and geographic applicability. Results: Standardized rates have fallen in many countries, while absolute case numbers continue to rise. Increases reported in some younger groups do not establish a uniform global trend because age definitions and registry coverage differ. Helicobacter pylori is a major causal factor, but mucosal damage, hereditary susceptibility, and other exposures affect risk. Randomized trials support eradication for reducing primary and metachronous cancer incidence. Screening associations with earlier diagnosis and lower mortality are largely observational and concentrated in East Asia. Conclusions: Prevention requires treatment of Helicobacter pylori and confirmation of cure. Advanced or extensive atrophy or intestinal metaplasia, autoimmune gastritis, and defined hereditary syndromes require the appropriate surveillance or specialist assessment. Family history, migration background, and behavioral exposures inform further assessment but are not equivalent indications for surveillance. Population screening and targeted assessment should follow local disease burden, antimicrobial resistance, and endoscopy capacity.