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Gastric Carcinomas Associated with H. pylori Infection

H. pylori infection correlates with higher risk for distal gastric cancer and lower risk for proximal gastric cancer.

Helicobacter pylori infection increases overall risk for gastric cancer. The incidence of distal gastric cancer is decreasing in the U.S. and other western countries, but the incidence of proximal gastric cancer, including cancers of the distal esophagus, gastroesophageal junction, and cardia, is increasing. This shift in localization of gastric cancer is occurring as rates of infection with H. pylori are declining in the western population.

In this large case-control study, more than 29,000 male smokers (age range, 50–69) from Finland, who were enrolled in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, were assessed for gastric cancer risk. From 1985 through 1993, study participants received either vitamin supplements or placebo. During 14 years of follow-up, 173 noncardia and 61 cardia incident cancer cases were reported. Age-matched, cancer-free participants served as controls. Prestudy serum samples were tested for antibodies against H. pylori whole-cell and CagA antigens: 84% of gastric cancer case patients and 75% of controls were seropositive; seropositivity was significantly more common among case patients with noncardia than among those with cardia cancers (93% vs. 59%). H. pylori exposure conferred a relative risk of 4.50 (95% confidence interval, 2.34–8.65) for noncardia cancers and 0.49 (95% CI, 0.29–0.88) for cardia cancers. Prevalence of H. pylori exposure was significantly lower for patients with cardia cancers than for controls.

Comment: The results of this western case-control study of gastric cancer in a large cohort support the association of H. pylori infection with development of noncardia gastric cancers. The inverse relation of H. pylori infection to risk for cardia cancers suggests that the decline in H. pylori infection rates is related to the shift of gastric cancer to more proximal locations. This prompts an intriguing hypothesis: The rise in cardia gastric cancer incidence might be related to loss of potential protective effects of H. pylori (lower gastric acid output and less gastroesophageal reflux) against esophageal and proximal gastric cancers.

— David H. Ilson, MD, PhD

Published in Journal Watch Oncology and Hematology December 4, 2006

Citation(s):

Kamangar F et al. Opposing risks of gastric cardia and noncardia gastric adenocarcinomas associated with Helicobacter pylori seropositivity. J Natl Cancer Inst 2006 Oct 18; 98:1445-52.

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