Breast cancer survivors
Healthy people with average cancer risk
Women under 45
Women over 45
National guidelines recommend that patients meet with a genetics expert before undergoing genetic testing for cancer risk. Genetic counseling can help patients decide whether genetic testing is right for them and order the most appropriate test. Once test results are available, genetics experts also help patients understand their results. Over the last decade, the popularity of direct-to-consumer (DTC) genetic testing, such as 23andMe has grown. Some genetic tests are marketed to consumers on television, in print advertisements, and on the Internet. These “at-home” genetic tests give people direct access to their genetic information without first involving a healthcare provider in the process. A recent report outlines the benefits and limitations of DTC genetic testing. (10/20/17)
|At home test identifies mutation carrier||Questions for your doctor|
|Risks of at-home testing||Guidelines|
|What does this mean for me?||Resources and references|
A July 2017 ABC TV Baltimore news segment by reporter Mallory Sofastaii highlighted the story of Lara Diamond, who ordered a 23andme at-home genetic test to learn more about her genealogy. She expected the test to expand her family tree and locate distant relatives. Instead, she learned she had inherited a BRCA2 mutation.
Diamond immediately followed up with her doctor and a genetic counselor, and was diagnosed with Stage 1 breast cancer after she had a screening breast MRI. She had no prior knowledge of family history of breast cancer. She states, “There were no symptoms. I mean I wouldn't have gotten screened for years. The fact that a mammogram couldn't see it, ultrasound couldn't see it, it would've been a couple more years until there were any symptoms that would've made us question anything.”
While the at-home test enabled Diamond to be proactive about her health, the author of the news report stated that not everyone who has used DTC genetic testing has shared a positive experience. In fact, in November 2013, the FDA stopped 23andMe from sharing such results because of risks associated with false positive findings.
It’s important for consumers to understand that these genetic tests do not give a diagnosis. Even a genetic predisposition for a disease, such as late-onset Alzheimer's, doesn't guarantee that you will develop it. The test merely suggests that you may be predisposed. For some diseases, there are other factors such as environmental factors and lifestyle choices that may influence whether someone will get a particular disease. Genetics counselors are experts who are trained to look at an individual’s personal and family health history in order to help people better understand their risk for disease and their options for staying healthy.
The news report addresses some concerns and risks associated with DTC genetic testing and references the National Society of Genetic Counselors' (NSGC) position on Direct Access to Genetic Testing. The NSGC recommends caution when interpreting results at home. The author of this article interviewed Natalie Beck, a certified genetic counselor at the Johns Hopkins Institute of Genetic Medicine, who said, “It's not as simple as one single variant or one single gene and giving people an absolute increase or decrease risk for their health. And that challenge of patients trying to interpret their own genetic test results, I think, can lead to a lot of false anxiety or maybe even false reassurance.” Ellen Matloff, a certified genetic counselor and President & CEO of My Gene Counsel, explains that “Some patients who had 23andMe testing believed that they had been screened for all mutations in BRCA1 and BRCA2. In reality, they had only been screened for the three common Jewish BRCA mutations—a result which is almost meaningless in anyone not of Jewish ancestry.”
Most DTC genetic tests are not meant to provide health information. This changed in April 2017 when the FDA granted 23andMe permission to market its Personal Genome Service Genetic Health Risk tests for 10 diseases. These are the first DTC genetic tests the FDA has allowed to provide health and genetic information directly to consumers and not healthcare providers.
If you are considering at-home genetic testing, it’s important to understand what a test may or may not tell you, how reliable the test is, and whether you will receive any guidance to help you understand what the test results mean for you and your family. The NSGC recommends answering the following questions before submitting a DNA sample for a DTC genetic test:
Lastly, if you have already had a DTC genetic test, show your test results to your doctor or genetic counselor so that you can discuss them together.
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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: