Individual Risk Factors

Growing older is the biggest risk for breast cancer. The longer you live, the higher your risk:

• From birth to age 39, 1 woman in 231 will get breast cancer (<0.5% risk).
• From ages 40–59, the chance is 1 in 25 (4% risk).
• From ages 60–79, the chance is 1 in 15 (nearly 7%).

The risk of getting breast cancer over the course of an entire lifetime, assuming you live to age 90, is one in 7, with an overall lifetime risk of 14.3%.

Risk increases with age because the wear and tear of living increases the risk that a genetic abnormality, or "mistake," will develop that your body doesn't find and fix.

Personal history of breast cancer is a risk factor for breast cancer recurrence or the formation of a new breast cancer. In other words, if you have already been diagnosed with breast cancer, your risk of developing it again is higher than if you had never had the disease. The risk is about 1% per year, so that over a 10-year period, your risk would be about 10%. However, there is medication available to help you reduce that risk.

Family history of breast cancer can have a significant impact on your risk, but don't automatically assume that any case of breast cancer in your family means you are a high-risk candidate. For example, if your grandmother was diagnosed with breast cancer at age 75, this does NOT mean your risk of the disease is increased. Your grandmother was most likely just one of the 1 in 15 women in that age bracket who gets breast cancer from the wear and tear of aging.

Other patterns of family history may strongly suggest an inherited gene abnormality that is independent of normal aging, and is associated with a relatively higher risk of breast cancer. The following signs suggest that there may be an inherited gene abnormality in your family (These apply to either your mother's OR your father's side of the family):

• having a mother, sister, or daughter with breast cancer
• having multiple generations of family members affected by breast or ovarian cancer
• having relatives who were diagnosed with breast cancer at a young age (under 50 years old)
• having relatives who had both breasts affected by cancer

You can inherit a breast cancer gene abnormality from your mother OR your father. If one of your parents has a gene abnormality, you have a 50% risk of inheriting the gene from him or her. If you do inherit a gene abnormality, your risk of developing the disease depends on the specific abnormality found, the pattern of its behavior in your family, plus the uniqueness of your own body. The risk of breast cancer in these families ranges greatly—from 40–80% over the course of a lifetime. Keep in mind that breast cancer caused by an inherited gene abnormality is not necessarily any more severe or less treatable than other types of breast cancer.

Certain types of breast cancer gene abnormalities are also associated with a higher risk of ovarian cancer (from 20–60%).

Genetic counseling can help you better define and understand the significance of your own family history.