Ovarian Cancer - Causes

Identifying and Screening High-Risk Women

Risk Factors for Inherited Ovarian Cancer

Women are considered at high risk for ovarian cancer if they have:

• A first-degree relative (mother, sister, or daughter) with ovarian cancer at any age. The risk increases with the number of affected first-degree relatives.
• A first-degree relative (or two second-degree relatives on the same side) with early onset breast cancer (occurring before age 50).
• A family member with both breast and ovarian cancer.
• A family history of male breast cancer (which might indicate a BRCA2 mutation).
• A family history of hereditary nonpolyposis colorectal cancer.

When a woman describes her family history to her doctor, she should include the history of cancer in women on both the mother's and the father's side. Both are significant.

Screening High-Risk Women

It is now possible to test for genetic mutations in the BRCA1 and BRCA2 genes and for hereditary nonpolyposis colorectal cancer (HNPCC) and Peutz-Jeghers syndrome in high-risk women. Any positive result raises difficult issues:

• The presence of a mutation in any of these genes does not predict with absolute certainty that either breast cancer or ovarian cancer will occur. The lifetime risk for BRCA1, for example, is significantly higher (up to 40%) than for BRCA2 (about 10 - 15%).
• Surgical preventive strategies, which can involve both mastectomy and removal of the ovaries, do not completely eliminate the risk for cancer, since malignant cells may occur in nearby regions. Removal of the ovaries will reduce ovarian cancer risk, however, and may also reduce breast cancer risk in mutation carriers.

Screening Guidelines for BRCA Genes

In 2005, the U.S. Preventive Services Task Force (USPSTF) released updated guidelines for BRCA testing. While women at high risk should be tested, the USPSTF does not recommend routine genetic counseling or testing for BRCA genes in low-risk women (no family history of BRCA 1 or 2 genetic mutations).