How Much Does a Family History of Breast Cancer Matter?

When it comes to breast cancer, how important is your family tree? We know that women with a family history of breast cancer are generally at higher risk for the disease. According to one recent study, women with two or more relatives who have had breast cancer were three and a half times as likely to develop breast cancer. Your risk of breast cancer is also higher if you have a first-degree relative, such as a mother or sister, who was diagnosed with it before age 50.

Despite such statistics, many women who are diagnosed with breast cancer have no family history of the disease. In fact, one study has found that eight out of nine women who develop breast cancer do not have a mother, sister or daughter with the disease. That same study found that most women who have a first-degree relative with breast cancer will never develop it, and that those who do are usually over 50 when their cancer is diagnosed.

Genetic Mutations and Breast Cancer Risk

It’s true that there are genetic factors that influence breast cancer. Your lifetime risk of developing it — or developing ovarian cancer — is much greater if you inherit a mutation in one or both of the BRCA genes. For example, about 12 percent of women will develop breast cancer, but about 72 percent of women who inherit a BRCA1 mutation and 69 percent of women who inherit a BRCA2 mutation will develop breast cancer by age 80. However, these mutations are relatively rare. It’s estimated that just one woman out of every 400 has a BRCA1 mutation, and only about one in 800 women has a BRCA2 mutation.

Other Breast Cancer Risk Factors

Other breast cancer risk factors influence whether a woman will develop the disease. Along with genetic mutations and a family history of breast cancer, there are other factors that can’t be changed, such as:

  • Age. Your risk of breast cancer increases as you get older.
  • Having dense breast tissue.
  • Starting your menstrual period before age 12, or entering menopause after age 55.

However, other breast cancer risk factors are modifiable, which means that you may be able to lower your odds of developing the disease by addressing them:

  • A sedentary lifestyle. You have a higher risk of breast cancer if you aren’t physically active.
  • Extra pounds. Being overweight or obese, particularly after menopause, is associated with a higher risk of breast cancer.
  • Supplemental hormones, including estrogen and progesterone. Taking hormones in the form of hormone replacement therapy or oral contraceptives (i.e., birth control pills) has been linked to higher rates of breast cancer.
  • Alcohol consumption. Women who regularly consume alcoholic beverages appear to be at higher risk of developing breast cancer.

If you’re concerned about your risk of breast cancer or want more information about modifying your risk factors, make an appointment with your physician at Lahey Hospital and Medical Center in Burlington, Massachusetts.


*The content on this website is for informational purposes only and is not medical advice. Please consult a physician regarding your specific medical condition, diagnosis and/or treatment.

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