Hereditary Breast and Ovarian Cancer

One in eight (12 percent) of U.S. women aged 90 years or younger will develop breast cancer sometime during her lifetime.

One in 70 (1.4 percent) will develop ovarian cancer.

Being female, increasing age, and family history of breast and/or ovarian cancer are the three greatest risk factors for breast cancer and ovarian cancer.

The majority of breast and ovarian cancers are not caused by an inherited genetic factor. However, 5 percent to 10 percent of all breast cancer is caused by a genetic change inherited from a parent. Patients with hereditary cancer face additional cancer risks themselves as do their family members. Identifying those at risk and providing access for a cancer risk assessment are important in providing the best care for all members of these families.

BRCA-1 and BRCA-2 are two genes that we know are related to breast and ovarian cancer risk. Some changes (mutations) in these genes increase the risk for breast and ovarian cancer.

Inherited mutations in genes other than BRCA-1 and BRCA-2 have been shown or are suspected to increase susceptibility for developing breast and other forms of cancer. Testing might be available for some of these mutations as well. A cancer risk assessment is most important in making sure appropriate genetic testing is offered.

Most women do not have a mutation in the BRCA-1 or BRCA-2 gene. The National Cancer Institute has stated that some factors increase the likelihood that a person carries an inherited BRCA mutation. They include:

  • A family history of several (three or more) close blood relatives (sisters, daughters, mother, grandmothers, aunts, cousins) affected with breast cancer, ovarian cancer, or both.
  • A family history of early onset (before 50 or before menopause) breast or ovarian cancer in one or more close blood relatives (sisters, daughters, mother, grandmothers, aunts).
  • A family history of one or more close blood relatives (sisters, daughters, mother, grandmothers, aunts) with two or more primary tumors of the breast or bilateral breast cancer.
  • A family history of one or more close male blood relatives (father, sons, brothers, uncles, grandfathers) who have developed breast cancer.
  • Ashkenazi (Eastern European) Jewish ancestry and a family history of breast and/or ovarian cancer.

Remember, both maternal and paternal family history is relevant for determining a person's risk for breast / ovarian cancer. It is important to ask about mom AND dad's family history related to breast cancer.

Women or men who meet one or more of the above criteria can contact their primary health providers for referral for genetic counseling and cancer risk assessment to discuss their risks for breast and / or ovarian cancer and whether BRCA testing is clinically appropriate for them.

The risks associated with mutations in BRCA-1 and BRCA-2 include a 50 percent  to 85 percent risk for developing breast cancer and a 10 percent to 45 percent risk for developing ovarian cancer. These risks are significantly increased over the risks for these cancers in the general population.

Information is limited on how other non-genetic factors influence the risks associated with these mutations. For people who have a BRCA mutation, clinical management choices may include increased or more intensive monitoring, chemoprevention, or prophylactic surgery to remove at-risk organs. Screening must be started at a young age, usually between the ages of 20-25 years of age.

Although some of these options may reduce the risk for developing breast and / or ovarian cancer, no option totally eliminates this risk.

Although the BRCA genes are the most common hereditary causes of breast and ovarian cancer, there are several additional genes that may also contribute to a family history of breast, ovarian or other cancers. Testing for these genes recently became available.

Additional Information

The National Cancer Institute (NCI) provides additional information on hereditary breast and ovarian cancer.

Last Updated 10/2016

Who Treats This

Who treats this?
Our Hereditary Cancer Program provides cancer risk-assessment services for children and adults. Our experienced team can evaluate your family history and choose appropriate genetic testing options to determine your child’s risk for familial and hereditary cancers. Learn More