How is it used?
There are hundreds of different BRCA-1 and BRCA-2
mutations present in the general population, but most of them are either rare or have not been associated with an increased risk of cancer. Standard BRCA-1 and BRCA-2 tests detect common mutations in the
genes, mutations that are known to increase the risk of
breast and
ovarian cancer development. Specific BRCA1 and BRCA 2 mutations are associated with some ethnic groups, such as those of Ashkenazi Jewish descent. If a BRCA-1 or BRCA-2 mutation has been identified in a family member with breast and/or ovarian cancer, then that mutation should be tested for in other family members.
Only about 0.2% of the U.S. population carries a BRCA-1 or BRCA-2 mutation. Because of this, screening is not recommended for the general population. BRCA testing should be considered for those women who do have close male or female relatives who have been diagnosed with breast cancer and/or have female relatives with ovarian cancer. This is especially true if the cancer occurred before the person was 50 years old. A person should also strongly consider testing if a BRCA-1 or BRCA-2 mutation has been identified in a family member. It is recommended that people be counseled by a health care provider knowledgeable in cancer genetics both before and after BRCA testing.
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When is it ordered?
BCRA testing is not recommended as a screening tool for the general population. Women with a strong family history of
breast cancer or
ovarian cancer or with a relative who has a BCRA-1 or BCRA-2 mutation often request this test, and this is its primary use. Someone who is considering testing should talk to her doctor and seek counseling by a knowledgeable health care professional prior to testing.
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What does the test result mean?
The degree of risk conferred with a positive result is difficult to quantify for a specific person. Results must be interpreted in conjunction with the tested person's personal and family history. A
genetic counselor/trained health care professional should explain the meaning of the results, explain treatment options for the individual that are intended to decrease risk, and testing options for other family members.
A negative result does not mean that a woman will not develop breast or ovarian cancer. It simply indicates that the person tested is not at increased risk for developing hereditary breast cancer or ovarian cancer related to the BRCA mutations for which he/she was tested. It is important to remember that 90-95% of breast cancers are not associated with a BRCA mutation. Furthermore, in the general population, the lifetime risk of developing breast cancer is approximately 12% and the lifetime risk of developing ovarian cancer is about 1.4%. The risks increase with age.
The presence of a BRCA-1 or BRCA-2 mutation means that the person tested is at an increased risk for breast and/or ovarian cancer, but it does not mean that she will ever have them. 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 National Cancer Institute (NCI), estimates of lifetime risk for breast cancer in women with BRCA-1 or BRCA-2 mutations is about 60% and estimates of risk for ovarian cancer ranges from 15% to 40%.
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Is there anything else I should know?
Positive 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 results with other 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 expertise to help sort through them.
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