Genetic testing provides people the chance to learn if their family history of breast cancer may be due to a BRCA1 or BRCA2 mutation. However, only 5 to 10 percent of breast cancers are related to a genetic mutation [2]. Most breast cancers do not have a genetic basis. But for the small number of people who have these mutations, the risk of breast cancer is greatly increased. In these cases, there are certain steps that people can take to try and decrease this risk. Find out more on BRCA1 and BRCA2 mutations and breast cancer risk.
Who should consider testing?
Genetic testing for BRCA1 and 2 is marketed as BRCAnalysis®. Although it is widely advertised, genetic testing is only recommended for some people including those:
- Who have a strong family history of breast cancer at an early age
- Who have a family history of breast and ovarian cancers
- Who have a family history of male breast cancer
- With Ashkenazi Jewish heritage who also have some family history of breast or ovarian cancer
If you or an immediate family member is the only person in your family to develop breast cancer, it is unlikely that your family carries a BRCA mutation.
Although BRCA testing requires just a blood sample, many risks and benefits should be considered before being tested. Because of the potential physical, emotional and financial impact of knowing one's genetic status, testing for the BRCA mutation is recommended only for families with a strong history of breast cancer.
Testing is first done on the family member who has been diagnosed with breast cancer. If no mutation is found in the family member with cancer, this means the cancer was probably not due to a genetic mutation and there is no need to test other family members. If a mutation is found, other family members can be tested for the specific BRCA mutation that was discovered.
BRCA1 and 2 mutations are the most common inherited mutations linked to an increased risk of breast cancer. Several known inherited mutations also increase risk, including those in the genes p53 and PTEN/ MMAC1. Other genes are being evaluated for their role in breast cancer risk. Testing exists for some of these mutations, but is not often done because the mutations are much rarer than those in BRCA 1 and 2.
A health care provider or genetic counselor can help you consider the issues related to genetic testing. For more information, visit the National Cancer Institute's genetic testing website at http://www.cancer.gov or call its hotline at 1-800-4-CANCER.
Genetic test results
Results from a BRCA test show whether or not there is a mutation related to cancer in the BRCA genes. There are three possible results from BRCA testing: no mutation (negative), a cancer-associated mutation (positive or carrier) or a variant of uncertain significance (a mutation that is not currently known to increase breast cancer risk). Having a BRCA mutation does not mean that you will definitely develop breast cancer. And, not having a mutation means you are still at some risk of breast cancer. If you have a BRCA mutation, there are steps you can take to lower your risk of breast cancer. You should discuss these steps with your health care provider. For more on this, visit the Early Detection and Screening chapter. Regardless of your mutation status, you can take steps to lower your breast cancer risk. For more on risk factors and prevention, click here.
Psychological/emotional risks of genetic testing
If you are thinking about genetic testing, you should consider the psychological impact of genetic test results. For those who carry a mutation, the knowledge can be distressing even though they may never go on to develop breast cancer. On the other hand, those who do not have a mutation may feel a false sense of security about not being at risk. And for those with a variant of uncertain significance, not knowing whether such a mutation is simply a normal variation in the gene or truly something to be concerned about can increase anxiety during an already trying process.
No matter the test result, it is important to follow age-appropriate breast cancer screening recommendations. There are special screening recommendations for those with a BRCA mutation as well as those with no genetic mutations but with a strong family history of breast cancer or other factors that greatly increase risk. For more on this, visit the Early Detection and Screening chapter. Talking with a genetic counselor or health care provider can help you to better understand your risk of breast cancer and develop a breast health plan.
Other considerations include the emotional impact that testing may have on family members. If a woman finds she has a BRCA mutation, this information may affect her siblings and children, possibly causing them worry and anxiety.
Other risks of genetic testing
Genetic testing should be confidential. However, if results are mistakenly or purposefully made available to a health insurer or employer, there is the possibility for discrimination. Fortunately, state and federal laws protect against genetic discrimination, including the Genetic Information Nondiscrimination Act (GINA), which was signed into law in May 2008 and will go into effect in May 2009. This federal law prevents health insurers from denying coverage or charging higher premiums when a person's genetic profile puts them at higher risk for certain health conditions. GINA also protects against genetic discrimination from employers.
There have been no court cases of genetic discrimination regarding the BRCA1 and 2 gene mutations since the tests were introduced.
Benefits
One benefit of testing includes knowing your genetic status, which in turn allows you to make decisions based on the test results. If there is a mutation, you may reduce your chances of developing breast cancer by taking a risk-lowering drug, like tamoxifen or raloxifene or by having a prophylactic mastectomy (for more on these options, click here). Knowing if you carry a mutation will also allow you to be screened at a younger age and more frequently. Breast MRI is now recommended for screening BRCA1 and BRCA2 carriers because they appear to be more accurate than mammograms at detecting breast cancer in women with these mutations.
In addition, women who know they have a BRCA1 or BRCA2 mutation may consider screening and prevention options to reduce the risk of ovarian cancer including oophorectomy (for more on this, click here). People can also share their genetic test results with family members, who may benefit from them.
Other benefits of knowing genetic status include the opportunity to participate in breast cancer research studies exploring new prevention methods that may benefit others in the future. To search for clinical trials recruiting those with BRCA or other genetic mutations, visit the National Institutes of Health website at http://clinicaltrials.gov.
Updated 09/14/09
