How Much Do Genetics Impact the Risk for Breast Cancer?

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What causes breast cancer? How much do genetics impact the risk for developing breast cancer? Given that 1 in 8 women will develop the disease, these are common questions many women and their families ask.

Stephanie Graff, MD, medical oncologist at Sarah Cannon Cancer Institute at HCA Midwest Health in Kansas City, answers common questions.

Staphanie Graff, M.D.
Dr. Stephanie Graff at HCA Midwest Health 

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

Women with one or more first-degree relatives who have had breast cancer have approximately double the risk than then general population of developing breast cancer. A first-degree relative is a mother, sister or daughter. Family history of other cancers, such as ovarian cancer, could also lead to an increased risk of breast cancer.

According to the National Cancer Institute, breast and ovarian cancers have been linked to specific mutations in BRCA1 and BRCA2 (genes that, when functioning normally, produce proteins that help repair damaged DNA and manage a cell’s genetic stability) – with 20 to 25 percent of hereditary breast cancers driven by the mutations in BRCA1 and BRCA2 and about five to 10 percent of all breast cancers linked to BRCA1 and BRCA2 mutations. Other genetic mutations have also been linked to breast cancer, such as PALB2 and TP53.

What should I do if I am at risk?

If you are at a high risk for breast cancer, talk with your doctor to determine the best screening schedule for you. Sarah Cannon recommends that an annual mammogram screening for women ages 40-74 should be a routine care consideration.

Healthcare professionals emphasize that there is value in conducting a regular breast self-exam in order to help identify breast cancer in its early stages. Sarah Cannon recommends that women ages 20+ conduct monthly breast self-exams.

What about genetic testing?

The United States Preventive Services Task Force has made the following recommendation for women considering genetic testing for BRCA mutations:

  • Women who have family members with breast, ovarian, fallopian tube or peritoneal cancer 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 family history 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— some look the mutations in one of the genes and others check for all possible mutations in both genes. The samples for testing typically involve DNA extracted from blood or saliva, and usually take about one month for results. 

Sarah Cannon Cancer Institute at HCA Midwest Health offers cancer genetic risk assessments and genetic counseling to women who have concerns about their personal and/or family history of cancer. Patients are provided with personalized information regarding genetic influences, specific cancer risks and targeted screening and prevention options.

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