Who should consider genetic testing for BRCA1 and BRCA2 mutations?
Because harmful BRCA1 and BRCA2 gene mutations are relatively rare in the general population, most experts agree that mutation testing of individuals who do not have cancer should be performed only when the person’s family history suggests the possible presence of a harmful mutation in BRCA1 or BRCA2. The likelihood of a harmful mutation in BRCA1 or BRCA2 is increased with certain familial patterns of cancer. These patterns include the following15:
- Multiple breast and/or ovarian cancers within a family (often diagnosed at an early age)
- Two or more primary cancers in a single family member (more than one breast cancer, or breast and ovarian cancer)
- Cases of male breast cancer
In a family with one of these cancer history patterns, it may be most informative to first test a family member who has breast or ovarian cancer if that person is still alive and willing to be tested. If that person is found to have a harmful BRCA1 or BRCA2 mutation, then other family members may want to consider genetic counseling to learn more about their potential risks and whether genetic testing for mutations in BRCA1 and BRCA2 might be appropriate for them.
Even if it is not possible to confirm the presence of a harmful BRCA1 or BRCA2 mutation in a family member who has cancer, women with a family medical history that suggests the presence of such a mutation may also want to consider genetic counseling and possible testing. Several professional organizations and expert groups, such as the United States Preventive Services Task Force, have developed clinical criteria that can be helpful to health care providers in identifying individuals for whom BRCA1 or BRCA2 mutation testing may be appropriate.15
Some women—for example, those who were adopted at birth—may not know their family history. If a woman with an unknown family history has an early-onset breast cancer or ovarian cancer, it may be reasonable for her to consider genetic testing for a BRCA1 or BRCA2 mutation. Women with an unknown family history and who do not have an early-onset cancer, even if they think they have an Ashkenazi Jewish background, are at very low risk of having a harmful BRCA1 or BRCA2 mutation and are unlikely to benefit from genetic testing.
Professional societies do not recommend that children, even those with a family history suggestive of a BRCA1 or BRCA2 mutation, undergo genetic testing. This is because no risk-reduction strategies for children exist, and their risk of developing a cancer type associated with a BRCA1 or BRCA2 mutation is extremely low. After they become adults, however, they may want to obtain genetic counseling about whether or not to undergoing genetic testing.
Should people considering genetic testing for BRCA1 and BRCA2 mutations talk with a genetic counselor?
Genetic counseling is generally recommended before and after any genetic test for an inherited cancer syndrome. This counseling should be performed by a health care professional who is experienced in cancer genetics. Genetic counseling usually covers many aspects of the testing process, including:
- A hereditary cancer risk assessment based on an individual’s personal and family medical history
- Discussion of:
- The appropriateness of genetic testing
- The medical implications of a positive or a negative test result
- The possibility that a test result might not be informative (see Question 12)
- The psychological risks and benefits of genetic test results
- The risk of passing a mutation to children
- Explanation of the specific test(s) that might be used and the technical accuracy of the test(s)