How much do genetics impact the risk for breast cancer?

Given that 1 in 8 women will develop breast cancer, there are important questions many women and their families should ask, including what causes breast cancer and how much do genetics impact the risk of breast cancer.  Erika Hamilton, MD, Director of Breast Cancer and Gynecologic Cancer Research for Sarah Cannon Research Institute, answers these common questions.

How much do genetics impact the risk for developing breast cancer?

According to the National Cancer Institute, some breast and ovarian cancers have been linked to specific mutations in the BRCA1 and BRCA2 genes. When functioning normally, BRCA1 and BRCA2 produce proteins that help repair damaged DNA and manage a cell's genetic stability. Approximately 15% of genetically mediated breast cancers are caused by mutations in BRCA1 or BRCA2, but other genetic causes of breast cancer do exist. While experts have identified numerous genetic causes of breast cancer, only about 5-10% of breast cancer can be identified as genetically mediated. Other genetic mutations have also been linked to breast cancer, such as PALB2 and TP53.

What should I do if I am at risk of developing breast cancer?

If a woman is at a high risk for breast cancer, she should speak with her doctor to determine the best screening schedule for her. Women should talk with their physicians regularly starting as early as age 25 about their individualized risk for breast cancer, as higher risk women may benefit from genetic counseling or early screening.

In addition to recommending that women talk with their physicians regularly starting as early as age 25 about their individualized risk for breast cancer, Sarah Cannon recommends that women ages 20-40 have a breast exam by their physician or practitioner every three years, and that women ages 40 and over should consult with their doctor annually about a mammogram. Additionally, Sarah Cannon recommends that starting at age 20, women should be familiar with their breasts and promptly report any changes to a healthcare provider.

What is genetic testing?

The United State Preventative Task Force has made the following recommendation for women considering BRCA genetic testing:

• Women who have a personal or family history of breast, ovarian, tubal, or peritoneal cancer, or an ancestry associated with BRCA 1/2 should be screened to see if their history is associated with an increased risk of carrying a genetic mutation. If so, then genetic counseling is recommended to determine if genetic testing would be useful.
• Women whose personal or family history or ancestry is not associated with increased risk for genetic mutations do not need routine genetic counseling or BRCA testing.

Several different types of genetic testing methods are available to detect genetic mutations, so it’s recommended that you have a conversation with your doctor about which test is right for you. The samples for testing typically involve DNA extracted from blood or saliva, and usually take one month for the results.

If you have questions about genetics and risk for breast cancer, call askSARAH at (844) 482-4812 to speak to a nurse who is specially trained to help with your cancer questions, or visit askSARAH online.

It is important to know that the information in this post, including Sarah Cannon’s recommendations for screening, is accurate as of the publishing date.