A 26-year-old woman presents to your office for her well-woman examination. She reports no medical problems or prior surgeries. She states that her cycles are monthly. She is sexually active and uses oral contraceptive pills for birth control. Her physical examination is normal. She reports that her 43-year-old paternal aunt was recently diagnosed with breast cancer and is undergoing treatment. She reports that her paternal grandmother died from ovarian cancer at the age of 75 years. She wants genetic testing (BRCA) for breast and ovarian cancer.
Which of the following statements regarding genetic testing for breast and ovarian cancer is true?
A. All female relatives of an individual with breast cancer should undergo genetic testingGermline mutations in BRCA1 and BRCA2 account for the vast majority of families with hereditary breast and ovarian cancer syndrome. Approximately 10% of cases of ovarian cancer and 3% to 5% of cases of breast cancer are due to germline mutations in BRCA1 and BRCA2. In the general population, it is estimated that approximately 1 in 300 to 1 in 800 individuals carry a mutation in BRCA1 or BRCA2. For a woman with a BRCA1 mutation, the risk of ovarian cancer is 39% to 46%. For a woman with a BRCA2 mutation, the risk of ovarian cancer is 12% to 20%. The estimated lifetime risk of breast cancer with a BRCA1 or BRCA2 mutation is 65% to 74%. Evaluating a patient’s risk for hereditary breast and ovarian cancer syndrome should be a routine part of obstetric and gynecologic practice. When evaluating a family history, it is important to remember that breast cancer and ovarian cancer predisposing genes can be transmitted through the father as well as the mother. If possible, genetic testing should begin with a person in the family who has ovarian cancer or early onset breast cancer (affected individual). For obstetrician–gynecologists, certain clinical criteria have been developed to assist in determining which patients would benefit from a genetic risk assessment. The first group of criteria includes those patients with greater than an approximate 20% to 25% chance of having an inherited predisposition to breast cancer and ovarian cancer and for whom genetic risk assessment is recommended. The second group of criteria includes those patients with greater than an approximate 5% to 10% chance of having an inherited predisposition to breast and ovarian cancer and for whom genetic risk assessment may be helpful. Although, in most cases, an inherited predisposition to ovarian cancer is caused by mutations in BRCA1 or BRCA2, current technology does not allow identification of all mutations that must exist in these genes.