Helicobacter pylori and the risk and management of associated diseases: gastritis, ulcer disease, atrophic gastritis and gastric cancer.

This review addresses the role of H. pylori and the effect of H. pylori eradication on gastritis, peptic ulcer disease, atrophic gastritis and gastric cancer. Specific emphasis is given to various factors that influence the clinical course of this infection. H. pylori induces chronic gastritis in virtually all infected subjects. This inflammation can lead to peptic ulceration and atrophic gastritis in a considerable number of infected subjects. A minority eventually develops gastric cancer. The risk of such complications depends upon the severity of gastritis, which is determined by various host- and bacteria-related factors. Among bacterial factors, most of the evidence addresses the cagA pathogenicity island, the presence of which has been associated with more severe gastritis, peptic ulceration, atrophic gastritis and gastric cancer. Among host factors, most of the evidence focuses on acid production in response to H. pylori infection. An increase in acid secretion limits H. pylori gastritis to the antrum at the risk of duodenal ulcer disease; a reduction allows more proximal inflammation at the risk of atrophic gastritis, gastric ulcer disease, and gastric cancer. Gastritis and atrophy negatively influence acid secretion. H. pylori eradication is required in peptic ulcer disease and may be advocated in patients on profound acid suppressive therapy; it has been shown to cure gastritis and prevent ulcer recurrence. Further study is required to determine the efficacy of H. pylori eradication in the primary and secondary prevention of atrophic gastritis and gastric cancer.