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Hereditary Breast and Ovarian Cancer

Except for skin cancer, breast cancer is the most common form of cancer in women; about 200,000 women in the United States are diagnosed with the disease each year. About 7 out of 100 women (or 7%) will get breast cancer by age 70; about 1 out of 100 women (or 1%) will get ovarian cancer by age 70. While ovarian cancer is less common, it is much harder to detect and often more serious. Most breast and ovarian cancers occur in women after the age of 50.

Most Breast and Ovarian Cancers Are Not Hereditary

  • Only about 5%–10% of breast and ovarian cancers are considered hereditary. These cancers are the result of inherited changes in single major genes which have a large effect, such as the breast cancer susceptibility genes BRCA1 and BRCA2. Hereditary cancers often affect several family members, and occur at young ages.
  • Some breast and ovarian cancers in families are the result of minor genetic factors combined with aging, the environment, and lifestyle.
  • Most breast and ovarian cancers are primarily due to aging, the environment, and lifestyle.

Family History Clues

You may be at increased risk of inheriting changes in the BRCA1/2 genes if your family history includes one or more of the following:

  • Several relatives with either breast or ovarian cancer.
  • Breast cancer at a young age (under 50).
  • A relative with cancer of both breasts.
  • A relative who had both breast and ovarian cancer.
  • A male relative with breast cancer.
  • Ashkenazi Jewish ancestry and any relative with breast or ovarian cancer.
  • A relative with a known BRCA1/2 genetic change.

Understanding BRCA Genes

BRCA1 and BRCA2 (BRCA1/2) are genes that normally protect you from getting certain cancers. Women who inherit a change in the BRCA1 or BRCA2 gene have a much higher risk of developing breast and/or ovarian cancer. But, important steps can be taken to help lower the risk for cancer in these women. Note that not everyone who inherits a BRCA1/2 change will get breast or ovarian cancer.

Breast Cancer Risk

Chart: About 7 out of 100 women in the U.S. general population will get breast cancer by the age of 70. About 93 out of 100 of these women will NOT get breast cancer by age 70.
Chart: About 50 out of 100 women with a BRCA1 or BRCA2 genetic change will get breast cancer by the age of 70. About 50 out of 100 of these women will NOT get breast cancer by age 70.

Women in the U.S. General Population
Icon: A woman. About 7 out of 100 women in the U.S. general population will get breast cancer by age 70.
Icon: A woman. About 93 out of 100 of these women will NOT get breast cancer by age 70.

Women with a BRCA1/2 Genetic Change
Icon: A woman. About 50 out of 100 women with a BRCA1 or BRCA2 genetic change will get breast cancer by age 70.
Icon: A woman. About 50 out of 100 of these women will NOT get breast cancer by age 70.

Ovarian Cancer Risk

Chart: About 1 out of 100 women in the U.S. general population will get ovarian cancer by the age of 70 About 99 out of 100 of these women will NOT get ovarian cancer by age 70
Chart: About 30 out of 100 women with a BRCA1 or BRCA2 genetic change will get ovarian cancer by the age of 70. About 70 out of 100 of these women will NOT get ovarian cancer by age 70

Women in the U.S. General Population
Icon: A woman. About 1 out of 100 women in the U.S. general population will get ovarian cancerby age 70.
Icon: A woman. About 99 out of 100 of these women will NOT get ovarian cancer by age 70.

Women with a BRCA1/2 Genetic Change
Icon: A woman. About 30 out of 100 women with a BRCA1 or BRCA2 genetic change will get ovarian cancer by age 70.
Icon: A woman. About 70 out of 100 of these women will NOT get ovarian cancer by age 70.


What about BRCA1/2 Genetic Testing?

Genetic testing is available to find out if a woman has inherited a change in either their BRCA1 or BRCA2 gene. However, most breast and ovarian cancer is not caused by these genetic changes, so BRCA1/2 genetic testing will be helpful only for a small number of women. If you are concerned about your family history, you should meet with a genetic counselor or other qualified health care professional to discuss:

  • Your family history.
  • Possible cancer risks.
  • Whether BRCA1/2 testing might be helpful.
  • Possible test results and impact on medical care.
  • Effect on family members.
  • Testing pros and cons.
 

More Information

 

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  • Page last reviewed: October 28, 2013
  • Page last updated: October 28, 2013
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