Proton pump inhibitors and H. pylori infection: why the concern?

Proton pump inhibitor therapy, even on a short-term basis, is associated with a decrease in antral gastritis and an increase in gastritis of the body. On a long-term basis, some series show the development of atrophic gastritis and some show none or hardly any. All studies fail to show or to report any significant increase in the prevalence of intestinal metaplasia with long-term PPI therapy. If one wants to determine whether PPIs cause atrophic gastritis with intestinal metaplasia, then the angularis primarily and the gastric antrum secondarily need to be studied because that is where most IM resides in the intestinal types of cancer. Instead of focusing on the angularis and antrum, the studies have evaluated biopsies from the gastric body, the least likely spot to be intestinalized in association with the intestinal type of gastric cancer [11]. H. pylori is associated with both intestinal and diffuse types of gastric cancer. Obtaining an answer to the question of whether PPI therapy or any other type of therapy increases gastric cancer risk in H. pylori-positive patients will require epidemiologic studies in which cancer is the end point. Intermediate theoretic markers are not available for diffuse cancers. If intermediate markers are used for the intestinal type of gastric cancer, then atrophic gastritis with intestinal metaplasia might provide some insight on theoretical grounds. However, the published long-term studies to date have not addressed that question because of where they have focused the biopsy sampling, and/or because of failure to report data on intestinal metaplasia.