How is it used?
The tests for BRCA-1 and BRCA-2 can tell you if you have
mutations in either of these two
genes that have been connected to the development of
breast and
ovarian cancer. Most people do not have a BRCA gene mutation (only about 1 in 800 people in the general population will have one) and the U.S. Preventive Services Task Force has recommended (September 2005) that BRCA genetic testing not be ordered as a screening test on women who do not have a strong family history of breast and/or ovarian cancer.
BRCA testing should be considered for those women who do have close relatives (male or female) who have been diagnosed with breast cancer and/or have female relatives with ovarian cancer. This is especially true if the cancer occurred at a relatively young age (prior to 50). A patient should also strongly consider testing if a BRCA mutation has been identified in another family member. It is recommended that patients be counseled by a health care provider knowledgeable in cancer genetics both pre and post testing.
Comprehensive analysis of both genes is typically performed for referred patients. In specific populations, such as those of Ashkenazi Jewish descent, testing may be targeted to diagnose only those mutations known to appear in that group of people. If a particular BRCA-1 or BRCA-2 mutation has been identified in a family member with breast and/or ovarian cancer, then that specific mutation should be tested for in other family members.
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When is it ordered?
Individuals with a strong family history of
breast cancer or
ovarian cancer often want this test performed. The test results may be used to decide whether to take steps that may prevent breast or ovarian cancer from developing in the future. Because we dont know how effective the options for prevention are, people who are considering taking this test should seek counseling by a knowledgeable health care professional. In this way, they can be sure of learning about and understanding the implications of the test result (see Is there anything else I should know? below).
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What does the test result mean?
Since there are hundreds of possible
mutations of BRCA
genes, test results must be interpreted by taking into account a persons family history. A
genetic counselor/trained health care professional should explain the meaning of the results and explain treatment options for the individual to decrease risk and testing options for other family members. Counseling on genetics should be offered both before testing occurs and after receiving test results.
A negative result does not mean that you cannot or will not develop breast cancer. It only means that you are not at risk for developing hereditary breast cancer related to the BRCA mutations for which you were tested.
The presence of a BRCA mutation means that the affected person is at an increased risk for developing breast and/or ovarian cancer. However, even within a family with the same BRCA mutation, not everyone will develop cancer, and those that do may develop it at different times during their life. According to the Centers for Disease Control and Prevention, estimates of lifetime risk for breast cancer in those with BRCA-1 or BRCA-2 mutations can range from 36%-85% and estimates of ovarian cancer from 16% to 60%.
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Is there anything else I should know?
Your test results may have implications for other family members. When one member of a family is tested for BRCA mutations, issues often arise about how or whether to share this information with other family members. Seek advice from a
genetic counselor about communication of result with your family members.
Pre and post test consultation with a health care provider knowledgeable about genetic testing cannot be overemphasized. There are many issues to be considered when preparing for a genetic test and upon learning the results, and a genetic counselor has the knowledge and experience to help you sort through them.
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