Gastric intestinal metaplasia: an intermediate precancerous lesion in the cascade of gastric carcinogenesis

Gastric intestinal metaplasia, an intermediate lesion in the development of intestinal-type gastric cancer, is observed in the milieu of long standing non-atrophic gastritis and atrophic gastritis. Most patients with intestinal metaplasia remain asymptomatic unless cobalamin deficiency occurs secondary to loss of glands (that produce intrinsic factor and acid). Genetic events that predispose to development of gastric intestinal metaplasia remains an enigma. Mechanisms leading to the progression of atrophy to metaplasia still needs to be comprehensively explored. Many studies in the literature describe a positive effect of typing intestinal metaplasia and concluded that intestinal metaplasia type III carries the highest risk for developing gastric cancer while others refute it. It is well established that Helicobacter pylori infection is the most important factor for the development of chronic gastritis, gastric intestinal metaplasia as well as gastric cancer. Countries with a higher prevalence of Helicobacter pylori infection and gastric cancer also have a high tendency of being prevalent for intestinal metaplasia. However, it remains elusive whether eradication of Helicobacter pylori infection tends to regress gastric intestinal metaplasia or reduce the subsequent risk of cancer development. Putting together, more prospective cohort studies should be designed to identify factors (antioxidants; anti-inflammatory drugs; food therapy) that may contribute in the regression of intestinal metaplasia, when used simultaneously with eradication therapy. Furthermore, molecular markers for evaluation of intestinal metaplasia, and the potential point-of-no-return should be further investigated. Consensus is also required to advocate a timeframe for surveillance of patients with gastric intestinal metaplasia. (author)