Washington, DC -- Evaluating a patient's risk of hereditary breast and ovarian cancer syndrome is an important first step in cancer prevention and early detection and should be a routine part of ob-gyn practice. Those who are likely to have the syndrome should be referred for further assessment to a clinician with expertise in genetics, according to a new Practice Bulletin jointly released today by The American College of Obstetricians and Gynecologists and the Society of Gynecologic Oncologists. The new document also provides information on how to counsel patients with hereditary risk in cancer prevention and how to perform surgical removal of the ovaries and fallopian tubes in this population.
Hereditary breast and ovarian cancer syndrome is an inherited cancer-susceptibility syndrome marked by multiple family members with breast cancer, ovarian cancer or both; the presence of both breast and ovarian cancer in a single individual; and early age of breast cancer onset.
"The vast majority of families who have hereditary breast and ovarian cancer syndrome carry an inherited mutation of the BRCA1 or BRCA2 tumor suppressor genes. Women in these families may have a higher risk of breast, ovarian, peritoneal, and fallopian tube cancers," said Karen Lu, MD, professor of gynecologic oncology at the University of Texas MD Anderson Cancer Center, who helped develop the ACOG Practice Bulletin. "Though having a BRCA gene mutation does not mean an individual will undoubtedly develop cancer, it is better to know sooner rather than later who may be at risk."
Women with either BRCA mutation have a 65%-74% chance of developing breast cancer in their lifetime. Lifetime risk of ovarian cancer is 39%-46% in women with a BRCA1 mutation and 12-20% in women with a BRCA2 mutation. Approximately 1 in 300 to 1 in 800 individuals in the US are BRCA carriers. BRCA mutations may occur more frequently in some populations founded by small ancestral groups, such as Ashkenazi (Eastern European) Jews, French Canadians, and Icelanders. An estimated 1 in 40 Ashkenazi Jews has a BRCA1 or BRCA2 mutation.
The new document addresses the ob-gyn's role in identifying, managing, and counseling patients with an inherited cancer risk. The initial screening evaluation should include specific questions about personal and family history of breast cancer and ovarian cancer. Because BRCA mutations can be passed down from both the father's and mother's side of the family, both sides of a woman's family should be carefully examined. Obtaining a full family history may be impeded in women who were adopted, those from families that have multiple women who had a hysterectomy and oophorectomy at a young age, or those from families with few female relatives. The results of a general evaluation will help determine whether the patient would benefit from a more in-depth hereditary cancer risk assessment, which should be conducted by a health care provider with expertise in cancer genetics.
Further genetic risk assessment is recommended for women who have more than a 20%-25% chance of having an inherited predisposition to breast or ovarian cancer. These women include:
- 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
Genetic risk assessment may also be appropriate for women with a 5%-10% chance of having hereditary risk, including:
- Women with breast cancer by age 40
- Women with ovarian cancer, primary peritoneal cancer, or fallopian tube cancer or high grade, serous histology at any age
- Women with cancer in both breasts (particularly if the first cancer was diagnosed by age 50)
- Women with breast cancer by age 50 and a close relative with breast cancer by age 50
- Women with breast cancer at any age and two or more close relatives with breast cancer at any age (particularly if at least one case of breast cancer was diagnosed by age 50)
- Unaffected women with a close relative that meets one of the previous criteria
Before testing, a genetic counselor can discuss the possible outcomes of testing; options for surveillance, chemoprevention, and risk-reducing surgery; cost and legal and insurance matters surrounding genetic tests and test results; and the psychologic and familial implications that may follow. The counselor can also provide written materials that women can share with family members who may also have an inherited risk.
Screening, Prevention, and Surgical Intervention
Those with hereditary breast and ovarian cancer syndrome can begin a screening and prevention plan based on individual risk factors and family history. Ovarian cancer screening approaches are currently limited. For women with a BRCA mutation, ACOG recommends periodic screening with CA 125 and transvaginal ultrasonography beginning between the ages of 30 and 35 years or 5-10 years earlier than the earliest age of first diagnosis of ovarian cancer in the family.
Risk-reducing salpingo-oophorectomy surgery—which removes both of the ovaries and fallopian tubes—can reduce the risk of ovarian and fallopian tube cancer by about 85% to 90% among BRCA carriers. Women who have BRCA1 or BRCA2 mutations should be offered risk-reducing salpingo-oophorectomy by age 40 or when childbearing is complete. The ideal time for this surgery depends on the type of gene mutation.
"In this population, risk-reducing salpingo-oophorectomy and pathology review must be extremely comprehensive to check for microscopic cancers in the ovaries, fallopian tubes, and abdominal cavity," Dr. Lu said. According to the Practice Bulletin, all tissue from the ovaries and fallopian tubes should be removed, and a complete, serial sectioning that includes microscopic examination for occult cancer should be conducted. A thorough visualization of the peritoneal surfaces with pelvic washings should be performed. Any abnormal areas should undergo biopsy.
Strategies recommended to reduce breast cancer risk in women with a BRCA mutation include semiannual clinical breast examination; an annual mammogram and annual breast magnetic resonance imaging screening beginning at age 25 or sooner based on the earliest age onset in the family; chemoprevention therapy with tamoxifen; and bilateral mastectomy to remove both breasts, which reduces the risk of breast cancer by greater than 90%-95%.
Practice Bulletin #103 "Hereditary Breast and Ovarian Cancer Syndrome" is published in the April 2009 edition of Obstetrics & Gynecology.