Contraceptive May Cut Risk of Breast Cancer, Study Finds

Efforts to find a hormonal contraceptive that also lowers a woman’s risk of breast cancer look promising, according to a USC study published today in the Journal of the National Cancer Institute.

The ongoing study by USC researchers involves giving women at high risk for breast cancer a special regimen of hormones that works as a contraceptive but may also decrease the breast-cancer risk. Women receive a monthly injection of a hormone called gonadotropin hormone-releasing agonist (GnRHA), which suppresses ovarian function. Doctors then give them small doses of estrogen and progesterone.

Mammograms of these women show a reduction in breast tissue density after one year on the hormones, which may also lower the cancer risk, said Dr. Darcy Spicer, an assistant professor of medicine at USC and the principal author of the study. Previous studies have shown that very dense breast tissue is associated with a higher risk of cancer.

“We think that this regimen should reduce the lifetime breast cancer risk by almost one-third if used for five years, and by more than 50% if used for 10 years,” Spicer said. “In addition, a substantial reduction in the risk of ovarian cancer is likely.”

In another study in the same journal, researchers in the Netherlands found that routine mammography benefits women over the age of 50 but not those younger than 50. Researchers suggest that screening in the older age group detects cancer at an earlier stage than among younger women.

But in an accompanying editorial, doctors noted that the Netherlands study may be flawed by the use of older mammography equipment that may be less sensitive than newer equipment.