Breastfeeding, Oral Contraceptives May Reduce Ovarian Cancer Risk Among Women with BRCA Mutations

Timothy R. Rebbeck, PhD

New data has revealed that breastfeeding, tubal ligation, and oral contraceptives may lower the risk of ovarian cancer for some women with BRCA gene mutations, according to a comprehensive analysis from a team at the University of Pennsylvania's Basser Research Center for BRCA and the Abramson Cancer Center.

Researchers found that breastfeeding and tubal ligation, also known as having one’s “tubes tied,” are associated with reduced rates of ovarian cancer in BRCA1 mutation carriers, and the use of oral contraceptives is associated with a reduced risk of ovarian cancer in patients with BRCA1 or BRCA2 mutations.

“Our analysis reveals that heredity is not destiny, and that working with their physicians and counselors, women with BRCA mutations can take proactive steps that may reduce their risk of being diagnosed with ovarian cancer,” lead author Timothy R. Rebbeck, PhD, professor of Epidemiology and Cancer Epidemiology and Risk Reduction Program Leader at Penn Medicine's Abramson Cancer Center, said in a statement. “The results of the analysis show that there is already sufficient information indicating how some variables might affect the risk of cancer for these patients."

The study also pointed to the fact that that some factors, such as smoking, may increase the risk of ovarian cancer in patients with BRCA2 mutations. The study shed some light on nonsurgical risk reduction options for women who may not be ready to undergo prophylactic removal of their ovaries to cut their cancer risk, but further data is needed in this area.

“Patients deserve better cancer—risk reduction options than surgically removing their healthy breasts and ovaries,” said Susan Domchek, MD, executive director of the Basser Research Center for BRCA and coauthor on the new paper said in a statement. “It’s imperative that we continue examining and building upon past research in this area so that we can provide BRCA mutation carriers with options at every age, and at every stage of their lives.”

While the study’s findings point to a helpful role for birth control pills in cutting ovarian cancer risk, the relationship between oral contraceptives and breast cancer risk was ambiguous. There was also insufficient evidence to draw conclusions about the relationships between breastfeeding and tubal ligation, respectively, and breast cancer. Future studies will aim to examine these issues as well as how other variables, such as alcohol consumption, affect the risk of breast and ovarian cancer for BRCA mutation carriers.

A woman's risk of developing breast or ovarian cancer is notably increased if she inherits a harmful mutation in either the BRCA1 gene or the BRCA2 gene from either parent. About 65% of women who inherit a harmful BRCA1 mutation and about 45% of women who inherit a harmful BRCA2 mutation will develop breast cancer by age 70, compared with approximately 12% of women in the general population.

Thirty-nine percent of women who inherit a harmful BRCA1 mutation and up to 17% of women who inherit a harmful BRCA2 mutation will develop ovarian cancer by age 70, compared to only 1.4% of women in the general population.

Both BRCA mutations have also been associated with increased risks of several other types of cancer.

The study findings were published online May 13 in the Journal of the National Cancer Institute.