4 Concerns About At-Home Genetic Testing for Cancer Risk
Genetic testing kits are changing the way we assess cancer. What's the catch?
Posted Aug 22, 2018
This entry was written in collaboration with Jennifer Bowers, M.A.
Advances in genetics have revolutionized the way we assess risk for, diagnose, and treat cancer. Now, consumers can purchase their own genetic testing kits to use at home, also known as direct-to-consumer genetic tests. One prominent company in the industry, 23AndMe, recently received approval from the FDA to test for three breast cancer mutations in the BRCA1 and BRCA2 genes this spring. While many in the fields of cancer and genetics are pleased to see this expanded access to testing, others argue that the issue is more complex, and that potential problems may arise.
One criticism of direct-to-consumer genetic testing made by psychologists is that the results received in the mail may not be easily interpretable. When people go to a genetic counselor for testing they can receive expert counsel to understand the results and what comes next for their health. Patients may also be referred to a clinical psychologist to manage symptoms, such as worry, and may be easily referred to other health professionals as needed. On the other hand, direct-to-consumer genetic testing results must be read and understood by the consumer, and no professional input is provided. Consumers are encouraged to follow up with their doctor by communicating their results, even if negative, but it is currently unclear if this is a common behavior. One study1 found that about a quarter of participants spontaneously followed up with their doctor after receiving results at home, but these individuals had higher incomes and were more likely to be health conscious already. There is a potential for misinterpretation or misunderstanding of results when read without a medical professional.
A second concern about testing for cancer risk at home is the ways in which the tests may be misleading. In the case of 23AndMe, only three breast cancer gene mutations are tested, yet there are over 1,000 known BRCA1 and BRCA2 mutations.2 The three that are tested by 23AndMe are not the most common in the general population. Thus, this test is not a complete assessment of risk. Psychologists who study how people understand risk are concerned about how people may behave following a negative result; if someone tests negative for breast cancer mutations using 23AndMe, they may be misled to believe their risk for breast cancer is reduced. However, breast cancer risk is complicated, involving several potential mutations, and other factors, such as family history. In a report by NPR on this topic,3 a woman felt relief after reading her negative results and admitted that she felt less urgency to get a mammogram. Before decisions to change preventive care are made, such as obtaining regular screening, a more complete assessment of risk should be completed.
The accuracy of direct-to-consumer tests have been called into question. Testing companies ask consumers not to regard their results as medical diagnoses to account for potential inaccuracies. While there are not yet systematic studies to determine the accuracy of such tests, one small study at a certified laboratory looked at 49 samples sent in from physicians whose patients were told they had a disease-causing mutation by their direct-to-consumer test. In this study, 40% were incorrect, and some of the information given to the consumers was also wrong.4 Given that this was only one study, more research needs to be done to better understand how accurate at-home genetic tests are.
Finally, privacy may also be a concern with your genetic material. A data breach recently occurred at a genetic testing company called My Heritage, which exposed 92 million users’ private information.5 One potential repercussion of breached privacy is concern about genetic discrimination. Although there are laws to ensure health insurance companies and employers do not discriminate using genetic information, there are not currently laws to protect from discrimination in seeking other forms of insurance, such as life and disability insurance.6 What testing companies may do with your data is also a potential concern; 23AndMe recently announced a partnership with a pharmaceutical company with the goal of using DNA to develop medical treatments.7 The potential for this to happen may have been laid out in the fine print, but the announcement took many consumers by surprise, and prompted concern. Now, 23AndMe and other companies have agreed to obtain express consent before transferring any data to a third party.
Assessing risk for cancer through genetic testing is an important advancement for early detection and prevention, and this advancement will save lives. For those lacking health insurance, direct-to-consumer genetic tests may be an accessible way to begin to understand this risk. These tests may also be helpful for making people feel more engaged and invested in their health. However, testing and following up with a medical professional is a more accurate and safe method for addressing the complicated medical issue of cancer risk.
1 Darst, B. F., Madlensky, L., Schork, N. J., Topol, E. J., & Bloss, C. S. (2014). Characteristics of genomic test consumers who spontaneously share results with their health care provider. Health Communications, 29, 105-108. doi:10.1080/10410236.2012.717216
2 American Cancer Society. FDA Approves Consumer Test for Certain BRCA Mutations. Retrieved from: https://www.cancer.org/latest-news/fda-approves-consumer-test-for-certain-brca-mutations.html
3 NPR. Results of At-Home Genetic Tests For Health Can Be Hard To Interpret. Retrieved from: https://www.npr.org/sections/health-shots/2018/06/18/609750963/results-of-at-home-genetic-tests-for-health-can-be-hard-to-interpret?utm_source=twitter.com&utm_medium=social&utm_campaign=npr&utm_term=nprnews&utm_content=20180618
4 Tandy-Connor, S., Guiltinan, J., Krempely, K., LaDuca, H., Reineke, P., Gutierrez, S., . . . Tippin Davis, B. (2018). False-positive results released by direct-to-consumer genetic tests highlight the importance of clinical confirmation testing for appropriate patient care. Genetics In Medicine. doi:10.1038/gim.2018.38
5 Bloomberg. Hack of DNA Website Exposes Data From 92 Million Accounts. Retrieved from: https://www.bloomberg.com/news/articles/2018-06-05/hack-of-dna-website-exposes-data-from-92-million-user-accounts
6 Genetics Home Reference. What is Genetic Discrimination? Retrieved from: https://ghr.nlm.nih.gov/primer/testing/discrimination
7 Scientific American. 23andMe Is Sharing Genetic Data with Drug Giant. Retrieved from: https://www.scientificamerican.com/article/23andme-is-sharing-genetic-data-with-drug-giant/