Genetics of Breast Cancer

David Arbutina, M.D., FACS

Family history or genetics are among the risk factors for breast cancer.  According to the National Cancer Institute, an estimated 5% to 10% of breast cancers are thought to be inherited making some women genetically predisposed to developing breast cancer.

The average woman in the United States has a 12%-13% chance of developing breast cancer.  Women who are genetically predisposed, with a BRCA gene mutation, have up to an 85% chance of developing the disease.  Genetic testing is used to determine if you are predisposed to breast cancer.  Your physician will determine the need for genetic testing.

Who needs to be tested?  Women who develop aggressive breast cancers prior to age 45 should be tested.  If a woman develops breast cancer and has two first degree relatives (mother, sister or daughter) with breast cancer they should also be tested.   If you develop breast cancer at age 55 and have 3 aunts who had breast cancer in their sixties, you don’t need tested.  However, if a family member is BRCA positive, every family member, both male and female, must be tested because there is a 50% chance of having a deleterious gene.  Knowing and acting on a positive test is lifesaving.

Remember, most women are not genetically predisposed to breast cancer.  However, it is important to know if you are in that small group of women who are at high risk because of your genetics.  Talk to your doctor about your unique breast health circumstances and follow your physician’s recommendations about the need for testing.