Study Shows Direct Link Between H Pylori and Gastric Cancer

ORLANDO—Researchers from Kure, Japan, reported on the first prospective study to show a direct connection between infection with Helicobacter pylori and the onset of gastric cancer. Their work, presented at the Digestive Disease Week meeting, builds upon epidemiologic research done in the early 1990s that strongly suggested such an association.

The study involved 1,166 patients with gastric disease who were tested for H pylori infection. The researchers took pains to ensure the accuracy of all negative readings. Each patient underwent three tests for the presence of H pylori: histology, a rapid urease test, and a serologic test.

“If all three tests were negative, we knew the patient was negative for H pylori,” Naami Uemara, MD, said in an interview. “Each test yields a false negative about 20% of the time. With three tests in agreement, you eliminate false negatives.” Dr. Uemara, chief of gastroenterology at Kure Kyosai Hospital, led the research team.

Of the total group, 246 were negative for H pylori while 920 were positive. Patients who tested positive for H pylori had the following diagnoses: chronic gastritis, (382 patients), active gastric ulcer (186), active duodenal ulcer (180), gastric polyp (172).

All patients underwent endoscopy at least once every 2 years. Therapy to eradicate H pylori was not employed in any of the patients. The follow-up period ranged from 5 to 8.5 years, and averaged 7 years.

Among patients free of H pylori, follow up endoscopy has revealed no cases of gastric cancer. In contrast, at the time of this analysis, the researchers had discovered gastric cancer in 17 of the 920 patients infected with H pylori (P < .05).

Histology revealed that 12 of the gastric cancers were of the intestinal type, and 5 were of the diffuse type. “This led us to conclude that, in humans, H pylori-associated gastritis causes the onset of both types of gastric cancer,” Dr. Uemara commented.