Role of therapy or monitoring in preventing progression to gastric cancer.

It is generally accepted that intestinal-type gastric adenocarcinoma arises through a multistep process originating with chronic gastritis, progressing through stages of atrophy, intestinal metaplasia, and dysplasia and finally invasive carcinoma. This sequential process, known as the "Correa cascade" is in many instances initiated by Helicobacter pylori infection and perpetuated by a number of environmental and host factors. Given that the development of carcinoma can be the end point of this sequential process, there is great interest in determining which if any of these steps may be reversible. Clinical studies have shown that the eradication of H. pylori can lead to resolution of chronic gastritis, and a few studies have suggested some improvement in gastric atrophy. Intestinal metaplasia, however, does not appear to be as reversible. Nevertheless, results of several intriguing studies of high-risk populations support the notion that eradication of H. pylori may decrease or delay progression to gastric carcinoma despite the inability to reverse all mucosal damage. The applicability of these findings to low-risk countries such as the United States and the United Kingdom remain uncertain. Currently, in the United States, there is no widely accepted screening program for H. pylori infection in asymptomatic individuals, and consensus regarding surveillance for gastric intestinal metaplasia or dysplasia is lacking. The purpose of this report is to evaluate the available data regarding the epidemiology of H. pylori and associated carcinoma, discuss relevant human and animal data that address eradication strategies in the prevention of gastric carcinoma, and finally discuss current recommendations regarding screening programs aimed at high-risk populations.