Breast cancer survivors
Healthy people with average cancer risk
Men with breast cancer
Ovarian cancer survivors
Triple negative breast cancer
Women under 45
Women over 45
Special populations: Men and women of Ashkenazi Jewish descent. People who are considering 23andMe testing.
Genetic testing for health conditions (such as risk for cancer) typically requires a prescription from a doctor. Until recently, direct-to-consumer (DTC) genetic testing has focused on tests to learn your ancestry and find of unknown branches of family trees. A laboratory called 23andMe that provides direct-to-consumer genetic testing has been given FDA approval to report results for 3 mutations found in the BRCA1 and BRCA2 genes. The FDA statement provides details about this approval and warns people about the limitations of the 23andMe test. (03/19/18)
|Direct-to-consumer testing||What does this mean for me?|
|Risks of DTC testing||Guidelines|
|Benefits of test||Resources and references|
|Testing without healthcare professionals|
With direct-to-consumer genetic testing, a person can order their own DNA test directly from the laboratory, with no doctor involved. In the past, testing for inherited mutations that raise the risk for disease has required a doctor's prescription. The FDA recently approved the first direct-to-consumer (DTC) test that looks for three mutations in the BRCA1 and BRCA2 genes. These mutations have been linked to increased risk for breast, ovarian, pancreatic, prostate and other cancers. This new approval allows people to order a kit, collect a saliva sample, send it directly to the 23andMe lab for testing, and receive their genetic results without involving a doctor.
People of Ashkenazi Jewish descent who have never had BRCA testing will have the most benefit from the 23andMe test. About 2% of all Ashkenazi Jewish people—regardless of personal or family history of cancer—will carry one of the 3 mutations in the 23andMe test.
However, even Ashkenazi Jewish people can have a mutation in one of the over 5,000 other BRCA mutations, or in another gene like CHEK2, ATM or PALB2. One study showed that among Jewish women with breast cancer, 0.8% have other BRCA mutations and 3 to 4% carry a mutation in another breast cancer gene (see our prior XRAY Does expanded genetic testing benefit Jewish women diagnosed with breast cancer?) These mutations are not detected in the 23andMe test. Therefore, negative results among Ashkenazi Jewish individuals are not conclusive either.
This new 23andMe DTC test has very limited usefulness for the general population. The test may benefit those who are unaware of their Jewish ethnicity and who test positive for one of the 3 mutations.
In DTC testing no medical or genetic counseling is included. Test results are returned electronically with a written explanation. Further questions and discussion of follow-up testing or treatment options are not included. As the FDA notes, this test should not be used to make health care decisions: “Consumers and health care professionals should not use the test results to determine any treatments, including anti-hormone therapies and prophylactic removal of the breasts or ovaries. Such decisions require confirmatory testing and genetic counseling. The test also does not provide information on a person’s overall risk of developing any type of cancer. The use of the test carries significant risks if individuals use the test results without consulting a physician or genetic counselor.”
The FDA examined how the test is performed and assures people that the test is accurate and reliable. The agency also warns that people should understand what this test does and does not tell them. They caution that without an expert explaining the meaning of the test results, misunderstandings may occur. Many genetics experts agree and believe that genetic testing for health information is best done in the clinical setting in consultation with medical professionals.
The 23andMe test can check your DNA for three specific BRCA mutations. Negative results provide very limited information, and are likely to be confusing to a person who undergoes testing without speaking to a genetics expert. Even if you are of Ashkenazi Jewish decent, you may have a mutation in BRCA1, 2 or other genes that are not included in this test.
Positive results may provide valuable information about risk for certain cancers, and options for manging these risks. However, because this testing is done without medical oversight, people should be aware of these important considerations:
At the present time, this approval does not lead to any changes in recommendations for genetic counseling and testing. The National Comprehensive Cancer Network is a consortium of experts in cancer and genetics. They publish consensus guidelines for genetic counseling and testing for cancer risk.
NCCN cautions about genetic testing through companies that provide ancestry testing (such as 23andMe). Commercial entities providing ancestry (and sometimes health) information typically do so through a type of testing known as “SNP-based testing”. This testing has not been validated for clinical use. Research suggests that the error rate for these tests may be substantial.
In their approval, the FDA make the following notes about test results through 23andMe:
After this report was published by the FDA, a large number of media sources covered it. This includes NBC News which published “FDA OKs 23andMe home breast cancer DNA test, with warning," containing a misleading graphic. FORCE covered the article in a recent Headline Hype blog post.
This direct-to-consumer test is a reliable way to identify 3 specific
BRCA mutations. Individuals who test negative may carry one of thousands of other mutations in BRCA1 or 2 or in a breast cancer gene that is not included in this test. Consumers may underestimate their risk of breast cancer and other cancers associated with these mutations, including ovarian cancer in women and prostate cancer in men.
For additional information read FORCE advisor board member and 2018 Spirit of Empowerment awardee Dr. Susan Domchek’s piece "At-home genetic testing may be convenient, but it isn’t complete" in Stat News.
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