Aspirin seen cutting risk of type of breast cancer

By Will Dunham

WASHINGTON (Reuters) - A daily aspirin may give women modest protection against the most common type of breast cancer, U.S. government researchers said on Wednesday.

The finding reinforced earlier research indicating regular use of aspirin might reduce the risk of so-called estrogen receptor-positive breast cancer, which makes up about three quarters of breast cancer cases.

Researchers led by Gretchen Gierach of the National Cancer Institute, part of the National Institutes of Health, found that women who took aspirin daily cut their risk of developing this type of breast cancer by 16 percent.

"If aspirin is truly risk-reducing, it would be a very exciting finding," Gierach said in a telephone interview.

Estrogen receptor or ER-positive breast cancer is fueled by estrogen and aspirin may interfere with this hormone's activity.

"Even though it's a small reduction in relative risk, since ER-positive breast cancers are the more common types, if this result is confirmed to be true it could have potentially a big public health impact," Gierach said.

The research involved about 127,000 women aged 51 to 72 from around the United States who were cancer-free when the study began. About 18 percent of the women were daily aspirin users. They were tracked for seven years and about 4,500 of them developed breast cancer.

The study did not find any relationship between aspirin and the less-common estrogen receptor-negative breast cancer. It also did not find any protective effect in women who took aspirin less than daily.