Overview of Current Concepts in Gastric Intestinal Metaplasia and Gastric Cancer.

Gastric intestinal metaplasia is a precancerous change of the mucosa of the stomach with intestinal epithelium, and is associated with an increased risk of dysplasia and cancer. The pathogenesis to gastric cancer is proposed by the Correa hypothesis as the transition from normal gastric epithelium to invasive cancer via inflammation followed by intramucosal cancer and invasion. Multiple risk factors have been associated with the development of gastric intestinal metaplasia interplay, including infection and associated genomics, host genetic factors, environmental milieu, rheumatologic disorders, diet, and intestinal microbiota. Globally, screening guidelines have been established in countries with high incidence. In the United States, no such guidelines have been developed due to lower, albeit increasing, incidence. The American Society for Gastrointestinal Endoscopy recommends a case-by-case patient assessment based upon epidemiology, genetics, and environmental risk factors. Studies have examined the use of a serologic biopsy to stratify risk based upon factors such as status and virulence factors, along with serologic markers of chronic inflammation including pepsinogen I, pepsinogen II, and gastrin. High-risk patients may then be advised to undergo endoscopic evaluation with mapping biopsies from the antrum (greater curvature, lesser curvature), incisura angularis, and corpus (greater curvature, lesser curvature). Surveillance guidelines have not been firmly established for patients with known gastric intestinal metaplasia, but include repeat endoscopy at intervals according to the histologic risk for malignant transformation.