Helicobacter pylori and gastric premalignant conditions

A hypothetical sequence occurs in the stomach from H. pylori infection to premalignant conditions. This sequence is characterized by several well documented steps. First, the H. pylori infection seems to be the main course of chronic gastritis, and is seen to be associated with gastritis at least in 80% of the cases. Second, chronic gastritis tends to slowly progress to atrophy and intestinal metaplasia of the underlying mucosa in a great proportion of affected subjects, this progression of chronic gastritis to atrophy being, however, multifactorial in nature, and being obviously affected also by factors other than the H. pylori. Third, there occurs an increased risk of gastric cancer in atrophic stomach (atrophic gastritis) with intestinal metaplasia, this risk being dependent upon the extend and grade of atrophic and metaplastic alterations in the stomach. Thus, it can be suggested that the H. pylori infection may trigger a sequence which will finally result in a development of conditions that favour the cancer formation. Recent epidemiological observations support this view: gastric cancer tends to be common in populations in which the H. pylori infection and the gastritis are common and in which the people will be commonly infected already in childhood, or in young age.