The American College of Obstetricians and Gynecologists (ACOG) and the Society of Gynecologic Oncologists (SGO) recommend routine assessment of a woman’s risk of hereditary breast and ovarian cancer, in order to identify those who may benefit from a more thorough hereditary cancer risk assessment. Women who eventually undergo genetic testing and are found to carry a BRCA1 or BRCA2 gene mutation have options available to manage their increased risk of cancer. These guidelines were published in Obstetrics and Gynecology.
Some families are at particularly high risk of cancer due to hereditary cancer syndromes. These families often have multiple family members with cancer and are more likely to develop cancer at a young age. In the case of breast and ovarian cancers, inherited mutations in two genes—BRCA1 and BRCA2—have been found to greatly increase the lifetime risk of developing breast and ovarian cancer. Mutations in these genes can be passed down through either the mother’s or the father’s side of the family. The lifetime risk of ovarian cancer is estimated to be 39-46% among women with a BRCA1 mutation and 12-20% among women with a BRCA2 mutation. Lifetime risk of breast cancer among BRCA1 or BRCA2 carriers is 65-74%.
An estimated 1 in 300 to 1 in 800 people in the United States have a BRCA1 or BRCA2 mutation. Questions about personal and family history of breast and ovarian cancer can help identify women who are at increased risk of carrying a BRCA mutation. When the chance of having a mutation is higher than 20-25%, additional genetic risk assessment is recommended. Women who fall into this category include the following:
- Women with a personal history of both breast cancer and ovarian cancer
- Women with ovarian cancer and a close relative—defined as mother, sister, daughter, grandmother, granddaughter, aunt—with ovarian cancer, premenopausal breast cancer, or both
- Women of Ashkenazi Jewish decent with breast cancer who were diagnosed at age 40 or younger or who have ovarian cancer
- Women with breast cancer at 50 or younger and who have a close relative with ovarian cancer or male breast cancer at any age
- Women with a close relative with a known BRCA mutation
Additional genetic risk assessment may also be helpful for some women with a lower (but still elevated) risk of hereditary breast and ovarian cancer. This includes women with breast cancer at a young age; women with bilateral breast cancer; women with high-grade serous ovarian, peritoneal, or fallopian tube cancer; women with breast cancer and two or more close relatives with breast cancer; and unaffected women with a close relative who meets one of these criteria.
When women are referred for additional genetic risk assessment, this often includes the collection of additional family history information, education, and counseling. Genetic testing may also be conducted. If a woman undergoes genetic testing and tests positive for a BRCA1 or BRCA2 mutation, she has several options for managing her risk of breast and ovarian cancer:
- Surveillance: women may choose to undergo regular cancer screening in order to detect cancer at an early stage. This screening may need to begin at an early age. Screening tests for breast and ovarian cancer include clinical breast exam, mammography, breast magnetic resonance imaging (MRI), CA 125 testing, and transvaginal ultrasonography. It’s important for women to be aware that there is still no clear evidence that screening for ovarian cancer reduces the risk of death from the disease.
- Chemoprevention: Hormonal therapy with tamoxifen has been shown to reduce the risk of breast cancer among women with a BRCA2 mutation. Tamoxifen may provide less of a breast cancer benefit among women with a BRCA1 mutation.
- Prophylactic (preventive) surgery: Bilateral prophylactic mastectomy (surgical removal of both breasts before cancer develops) greatly reduces the risk of breast cancer in women with a BRCA1 or BRCA2 mutation. Similarly, prophylactic removal of the ovaries and fallopian tubes reduces the risk of ovarian, fallopian tube, and peritoneal cancer. For women who are premenopausal, removal of the ovaries also reduces the risk of breast cancer.
Women may wish to discuss their personal and family history of breast and ovarian cancer with their physician in order to determine whether any further genetic assessment is warranted.