Birth Control Pills May Up Cancer Risk

Women who carry an inherited risk for breast cancer may have an even higher risk of the disease if they use birth control pills, according to a new study.

Inherited alterations in genes called BRCA1 and BRCA2 (short for breast cancer 1 and breast cancer 2) are involved in many cases of hereditary breast and ovarian cancer. Women with these gene mutations have a 50 to 80 percent lifetime risk of developing breast cancer, according to the study, published in Wednesday's issue of the Journal of the National Cancer Institute.

The study, led by Dr. Steven A. Narod of the Sunnybrook and Women's College Health Sciences Centre and the University of Toronto, looked at the oral contraceptive use of 1,311 women with BRCA1 or BRCA2 mutations who had breast cancer, and compared them to 1,311 women who had the gene mutation but didn't have cancer. The women were recruited from 52 centers in 11 countries.

Women with BRCA1 mutations who used oral contraceptives for five or more years had a 33 percent increase in breast cancer risk, compared to women who had never used the pills. The risk was also higher in women who used contraceptives before age 30, women who were diagnosed with breast cancer before age 40, and women who first used oral contraceptives before 1975.

In contrast, the researchers did not find any increase in breast cancer risk in BRCA2 mutation carriers, but they said that more studies should be done to confirm these findings.

But don't worry -- if you're a woman carrying a BRCA1 mutation, you could still safely use birth control pills after the age of 30, the point when researchers said the hormones are not likely to increase breast cancer risk. In fact, long-term oral contraceptive use has been linked to a decrease in the risk of ovarian cancer, according to the study.