Female Hormones Appear to Influence Risk for Gastric Cancer

By Will Boggs, MD

NEW YORK DEC 20, 2007 (Reuters Health) - Women with a high number of years of fertility seem to be protected to some degree against developing gastric cancer, according to a report in the December issue of Gut.

"Hormonal factors may affect gastric cancer risk," Dr. Neal D. Freedman told Reuters Health, "but future studies are required to determine whether or not this is the case."

Dr. Freedman from the National Cancer Institute, Rockville, Maryland and colleagues examined the association between reproductive and menstrual factors and gastric cancer risk in a large prospective study of 74,442 women from Shanghai, China.

Later age at menopause was associated with a significantly reduced risk of gastric cancer (hazard ratio, 0.80 per 5-year increase in menopausal age), the researchers report, and so was increased duration of fertility (HR, 1.90 for < 30 vs. 30-36 years fertility.)

On the other hand, increased years since menopause and intrauterine device use were associated with a significantly increased risk of gastric cancer.

Gastric cancer risk was not associated with age of menarche, number of children, breast feeding, or oral contraceptive use, the report indicates. There was a trend towards a lower gastric cancer risk with later age at first birth.

"Our results were consistent with those of previous studies in other countries," the investigators say, and are "consistent with the hypothesis that hormones such as estrogen and progesterone protect against the development of gastric cancer in women during the reproductive years."

"In future studies, we plan to directly test this hypothesis by determining whether circulating hormone levels predict gastric cancer risk," Dr. Freedman said.

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