Information about Hereditary Breast and Ovarian Cancer

The Facts about Hereditary Breast and Ovarian Cancer

  • About 1 in 10 women (10%) will get breast cancer in their lifetime.
  • About 1 in 100 women (1%) will get ovarian cancer in their lifetime.

Family history of breast and/or ovarian cancer increases these risks.

In some families, a single genetic factor passed from parent to child can greatly increase the risk for these cancers. This is known as hereditary cancer.

The most common inherited risk factor for hereditary breast and ovarian cancer is a change or “mutation” in one of the BRCA genes (BRCA1 or BRCA2).

Most women with breast or ovarian cancer do not have a BRCA mutation:

  • About 5% of breast cancers are caused by a BRCA gene mutation.
  • About 10 - 15% of ovarian cancers are caused by a BRCA gene mutation.

Who is most at risk for Hereditary Breast and Ovarian Cancer?

A personal or family history of one or more of the following may increase one’s risk:

  • Two or more cases of breast and/or ovarian cancer on the same side of family
  • Breast cancer before age 50
  • Ovarian cancer at any age
  • Breast and ovarian cancer in same person
  • Two primary (different) breast cancers in same person
  • Male relative with breast cancer
  • Pancreatic cancer
  • Ashkenazi Jewish ancestry
  • Triple negative breast cancer (estrogen, progesterone, and HER2 negative) diagnosed prior to age 60
  • Blood relative with known BRCA gene mutation

What does it mean to have a BRCA gene mutation?

Women with a BRCA gene mutation have a greatly increased chance of developing:

  • Breast cancer, especially at a young age
  • Ovarian cancer at any age

Men with a BRCA gene mutation are at increased risk for male breast and prostate cancer.

Increased risk for pancreatic cancer and melanoma also occur in families with a BRCA gene mutation.

Family members of people with a known BRCA gene mutation may have the same mutation and also be at risk for these cancers. There is a 50% chance for each of the children of a BRCA mutation carrier to inherit the mutation. Genetic testing can allow family members to learn if they do, or do not have an increased cancer risk.

If someone has a BRCA gene mutation, special screening and preventive steps can be taken to detect cancer earlyand lower her or his risk for cancer.

Cancer genetic counseling can help individuals and families understand their cancer risks, genetic testing, and screening and prevention options.

Other hereditary causes of breast and ovarian cancer

Other genes have been discovered that are associated with hereditary breast and other types of cancer.

It is now possible to test many genes, including BRCA1 and BRCA2, at the same time through a gene panel. The genes on these panels are each associated with varying risks for cancer including:

  • High risk genes
  • Moderate risk genes
  • Genes with uncertain risks

This type of panel testing is complex, and more likely to give results that are uncertain, or for which the best screening and prevention steps are unknown.

A cancer genetic counselor can determine if a gene panel test is appropriate for you/your and further explain the benefits and limitations of this type of testing.

Other risk factors for breast and ovarian cancer

REMEMBER: There are many other causes and risk factors for both breast and ovarian cancer besides family history and BRCA gene mutations. Click on the links below for more information.