WASHINGTON--An international panel of medical experts convened by the American Digestive Health Foundation released information, during Digestive Disease Week 1997, on the epidemiology, diagnosis, and treatment of Helio-bacter pylori, the bacterium known to cause most ulcers and also to be closely associated with gastric cancer.
The panel met earlier this year to update the information presented at the 1994 NIH Consensus Development Conference on H pylori. Highlights of the panel's findings, discussed at a recent press briefing, include:
- H pylori infection is frequently acquired during childhood.
- There is a link between H pylori and cancer as well as other diseases.
- New tests are available for diagnosis, and various therapies are available for treatment of H pylori infection.
- Research is needed to answer emerging questions, especially with respect to gastric cancer.
More than half of the world's population is infected with H pylori, and persons typically acquire it early in life.
"Humans are the major reservoir of H pylori, and evidence suggests that it is transmitted from person to person," said David A. Peura, MD, panel chair and professor of internal medicine at the University of Virginia Health Sciences Center.
There is strong evidence from population studies showing an association between H pylori and atrophic gastritis, a precursor to gastric cancer, Dr. Peura noted. Furthermore, recent blood sample studies show an association between H pylori and gastric cancer itself. The bacteria is also linked to 95% of mucosa-associated lymphoid tissue (MALT) lymphomas of the stomach.
Studies From Japan
Gastric cancer is relatively rare in the United States, said Colin Howden, MD, professor of medicine, University of South Carolina.
"We have to look to South America, Southeast Asia, and Japan, where the incidences of H pylori and gastric cancer are much higher," Dr. Howden said. "There are studies in progress involving the treatment of large numbers of people with H pylori to determine what effect that treatment will have on the occurrence of gastric cancer. The results are awaited with intense interest."
Since the 1994 NIH consensus conference, the FDA has approved two non-invasive tests for H pylori that are quick and reliable: an in-office blood test and a urea(Drug information on urea) breath test, Dr. Peura said. Both tests are widely available and relatively inexpensive, but the urea breath test is more sensitive and specific than the blood test, he added.
Endoscopy also is a useful diagnostic tool, but not always clinically necessary in patients who have a known cause for their symptoms.
The panel recommended testing for H pylori in patients with an active or documented duodenal/gastric ulcer or complicated duodenal/gastric ulcer. The decision to test other patients should be made on a case-by-case basis.
Treat With Combination Regimens
Further, the panel recommended treatment of H pylori with combination regimens, including up to three antibiotics along with an acid blocker, for all those who test positive. The panel could not conclude that any one FDA-approved treatment regimen offers an advantage over another.
The need for further research was labeled a high priority, and the panel identified several potential areas of study, including the impact of H pylori eradication on atrophic gastritis and gastric cancer, mechanisms of H pylori acquisition among children, and the possibility of vaccine development.