Long-term proton pump inhibitor use and gastrointestinal cancer.

Proton pump inhibitors profoundly affect the stomach and have been associated with carcinoid tumors in female rats. There is now sufficient experience with this class of drugs to allow reasonable estimation of their safety in terms of cancer development in humans. Long-term use of proton pump inhibitors is associated with an increase in gastric inflammation and development of atrophy among those with active Helicobacter pylori infections. The actual risk is unknown but is clearly low. However, it can be markedly reduced or eliminated by H. pylori eradication. It is thus recommended that patients being considered for long-term proton pump inhibitor therapy should be tested for H. pylori infection and, if present, this pathogen should be eradicated. Oxyntic cell hyperplasia, glandular dilatations, and fundic gland polyps may develop in patients not infected with H. pylori, but these changes are believed to be reversible and without significant cancer risk.