Eliminating a Common Bacterium Reduces Risk of Second Gastric Cancer
Adapted from the NCI Cancer Bulletin.
Researchers in Japan have shown that when the bacterium Helicobacter pylori is eliminated in patients who are treated for early stage gastric cancer, the risk of developing a second gastric cancer decreases by two-thirds. Their report appeared the August 2, 2008, issue of The Lancet (see the journal abstract).
H. pylori infects the stomachs of approximately half the people in the world and has been clearly linked to stomach problems, including peptic ulcers and cancer. Previous studies in animals have shown a preventive effect when the bacterium is eliminated, but results in human studies have been inconclusive.
The latest report, published by the Japan Gast Study Group, comes from an open-label study that included 544 patients aged 20-79 who were either newly diagnosed with gastric cancer and planning to undergo endoscopic surgery, or who had recently undergone surgery for gastric cancer. All patients had confirmed H. pylori infection. Those randomized into the test group received a combination of the antibiotics lansoprazole, amoxicillin, and clarithromycin twice a day for a week to prevent cancer recurrence, while those in the control group received standard care but no antibiotics.
The bacterium was eliminated from approximately 75 percent of patients who received the antibiotic regimen, and approximately 5 percent of patients from the control group. The only adverse effects of the antibiotic group with notable occurrence were soft stools and diarrhea. After three years of endoscopic monitoring, second gastric cancers occurred in nine patients from the treated group and 24 patients from the control group.
An accompanying editorial by Dr. Nicholas J. Talley of the Mayo Clinic in Jacksonville, Fla., discusses the benefits and drawbacks of widespread H. pylori screening and treatment, concluding, "Worldwide, gastric cancer kills more people [than colorectal cancer], and there is better evidence that H. pylori eradication can prevent mortality than there is for colonoscopy screening. Preventing gastric cancer by eradicating H. pylori in high-risk regions should be a priority."