Ovarian Cancer - Causes

The BRCA mutations can be passed down to the daughter by either the mother or the father. It should be noted that these mutations may occur in 5% to 10% of ovarian cancer patients who have no family history of breast or ovarian cancer. A number of studies have suggested that women with BRCA-mutated ovarian cancers tend to have better survival rates than others.

Other Genetic Mutations. Women who carry the hereditary nonpolyposis colorectal cancer (HNPCC) gene have about a 9% chance of developing ovarian cancer.

Identifying and Screening High-Risk Women

Risk Factors for Inherited Ovarian Cancer

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.

Note: When a woman describes her family history to her physician, 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% to 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.

Experts recommend genetic screening for women in very high-risk families, along with extensive counseling. Such rare families have several affected members with ovarian cancer, breast cancer, or both, usually occurring at a young age.

For women in high-risk groups, consideration of transvaginal ultrasound and CA-125 testing every six months to a year is reasonable, although the benefits of this approach are unproven.