At-Home Genetic Testing: Is It Right for You?
With more advances in personalized medicine, it makes sense that more and more people want to take charge of their health by learning about their personal genetic makeup and how they can use that information to reduce their disease risks. As we have previously written about, genetic factors can strongly influence cancer risk. Many direct-to-consumer (DTC) tests exist on the market today that will sequence parts of your genome and offer you a personalized genetic analysis ranging from ancestry to health risks.
UW Carbone Cancer Center genetic counselor Kelcy Smith, MMSc, helps us make sense of DTC tests, including what information they can provide – and, importantly with regards to cancer risk, what they do not.
Making Sense of Direct-to-Consumer Genetic Tests
Direct-to-consumer (“at-home”) genetic tests can provide lots of health information – but they are not diagnostic
DTC tests are those kits you can purchase at your local pharmacy and do not require a physician to order them. These testing companies, such as 23andMe, test for a range of things. They can tell you about your ancestry, traits such as baldness or dimples, or carrier status for genetic diseases such as Tay-Sachs or sickle cell anemia.
Some DTC tests say they will provide you with a risk assessment for cancer and other diseases, but here is where it is important to know how these tests differ from clinical ones.
DTC tests use a wealth of genetic data from research done on large groups of people, both those who had, say, breast cancer and those who did not. The genetics of these groups were compared and the various testing companies identified genetic differences between groups. The problem with these studies is that they are making the assumption that these genetic factors are increasing, or decreasing, risk for breast cancer. However, they are just correlations. Unlike clinical genetic tests, there is no evidence that these genetic differences have any effect on cancer development. Also, the results may differ between testing companies, meaning one test will say you’re at greater risk for breast cancer but another may say you’re actually protected based on which genetic markers the lab looks at.
Put another way: neither your health insurance nor your healthcare provider will approve or prescribe treatment plans based on your DTC genetic test results.
A physician- or genetic counselor-ordered genetic test looks for known cancer-associated gene mutations
The tests that we order in the genetic counseling clinic look for gene mutations that are proven by research to significantly increase one’s risk for developing cancer regardless of other factors. In addition, when we see patients in clinic, we look at their personal medical history, family medical history and additional lifestyle factors to assess an individual’s personal risk of having a hereditary cancer predisposition syndrome. We then are able to use that information to alter cancer screening and treatment plans for patients moving forward.
There are diagnostic at-home genetic tests that can provide you with accurate cancer risk information
Some genetic testing companies, such as Color, are diagnostic tests that can be done at home. They can be ordered by your clinician or the company’s physician. These tests test for the high-risk cancer genes and are diagnostic – meaning if you test positive for, say, a BRCA1 gene mutation, your provider will treat you as high-risk for breast cancer. The upside to these tests is that they are often more affordable than paying out of pocket for a genetic test in our clinic (though in most cases health insurance covers clinical genetic tests when prescribed). Also, these companies employ certified genetic counselors who will go over the results with you. The downside is that these tests do not have nearly as much flexibility in terms of what genes they can test for, and the results can be ambiguous. In clinic, we can order the specific panel that is right for you based on you and your family’s medical history. This specificity means we can more clearly interpret the results.
Before completing any genetic test, DTC or clinical, it’s important to ask yourself, “What’s my goal for genetic testing?”
I think the most important question to ask before any you undergo any genetic test is: What’s your goal? Are you trying to learn information for fun? Do you want to gather information on your family history or ancestry? If yes, then DTC tests are fine! In fact, there is some research showing that people who receive health information from a DTC genetic test make healthier lifestyle choices based on their results.
But if you are concerned about your cancer risk based on your family’s history, you would be a good candidate to talk with your primary care provider or oncologist about a referral to see a genetic counselor for a personalized cancer risk assessment and appropriate diagnostic genetic testing.
Date Published: 11/08/2017