Breast Cancer and Family Risk Factors

Although advancing age and being a woman are the two most significant risk factors for breast cancer, a family history also raises your risk of developing breast cancer and developing it at a younger age.

Breast Cancer Family History

You have a family history when one of these is true:

  • Two close relatives-mother, daughter, sister, grandmother, or aunt-were diagnosed with cancer before age 50
  • Three close family members were diagnosed before age 60
  • Four close family members were diagnosed at any age

Women may inherit known breast cancer genes-BRCA1, BRCA2, or TP53 (less common)-which are associated with an increased risk for developing breast cancer. Fortunately, they are relatively rare. Furthermore, inheriting these genes does NOT mean you inherit, or will develop breast cancer; you are just inheriting an increased risk.

Breast Cancer Managing Risk

Discuss your family history and risk profile with your physician. She may recommend genetic screening to determine if you are a BRAC1 or BRAC2 carrier, although you can be at high risk for breast cancer due to family history without carrying these genetic mutations. Genetic testing can give you an estimate of your risk, but cannot predict if you will or will not develop cancer.

You can't change your genetic profile. However, if you are at increased risk due to a family history, you have a few options to consider.

Surveillance: The Cancer Genetics Studies Consortium (CGSC) recommends high-risk women with the BRAC1 or BRAC2 genes have annual mammograms and annual or semi-annual clinical breast exams beginning between ages 25 and 35. However, there is some question as to whether BRAC carriers may be more prone to radiation-induced breast cancer, so discuss mammogram options with your physician.

Risk-reducing surgery: Mastectomy (removing the breasts) and oopherectomy (removing the ovaries) reduces much (but not all) of the risk of developing breast cancer. The ovaries and nearby adrenal glands produce oestrogen, a hormone that encourages breast cancer cell growth.

Chemoprevention: In some studies, the chemotherapy drug Tamoxifen shows protective effect against estrogen receptor positive breast cancer.

There is no one ideal risk-reduction strategy for women with a family history of breast cancer, and the National Cancer Institute says there's little data regarding the outcomes of risk-reducing interventions. Each strategy has its pros and cons. And ultimately, most breast cancers occur in women who do not have a family history.

Women must discuss all the options with their physician and make their own, informed decisions.

Breakthrough Breast Cancer. "The Best Treatment: Your guide to UK services for people with a family history of breast cancer." Web. March 2011.

National Cancer Institute. "Genetics of Breast and Ovarian Cancer (PDQ®)." Web. 25 February 2011.

Salhab, Mohamed, Bismohun, Selina, and Mokbel, Kefah. "Risk-reducing Strategies for Women Carrying brca1/2 Mutations with a Focus on Prophylactic Surgery." BMC Women's Health 10(1) (2010). Medscape Medical News. Web. 14 December 2010.

Roxanne Nelson. "AACR FCPR 2008: Family History Increases Breast Cancer Risk." Medscape Medical News. Web. 26 November 2008.