Direct-to-Consumer Genomic Testing Pros and Cons: Q&A
The PGen Study was a National Institutes of Health (NIH)-funded longitudinal survey of over 1800 consumers of 2 leading DTC genetic testing companies — 23andMe and Pathway Genomics.
Scott Roberts, PhD, is an associate professor in the department of health behavior & health education and director of the Genomics, Health & Society Program at the University of Michigan's Center for Bioethics & Social Sciences in Medicine, Ann Arbor.
He studies genetic risk assessment effects for patients at risk for adult-onset diseases and is principal investigator of the federally funded Impact of Personal Genomics (PGen) Study.
Soon after the US Food & Drug Administration (FDA) approved 23andMe's direct-to-consumer (DTC) genomic testing for several non-cancer diseases, Cancer Therapy Advisor asked Dr Roberts about the PGen Study and the implications for DTC cancer risk testing in the future.
Cancer Therapy Advisor (CTA): What are the goals of the PGen Study and what is it revealing about DRC gene testing?
Dr Roberts: The PGen Study was a National Institutes of Health (NIH)-funded longitudinal survey of over 1800 consumers of 2 leading DTC genetic testing companies — 23andMe and Pathway Genomics. (Pathway has since switched to a physician-mediated model.) A recent publication of mine highlighted key findings on the risks and benefits of genetic testing in this format.1
On the positive side, the majority of consumers (59%) said their test results would be useful in managing their health moving forward and very few (1% to 2%) reported regret about seeking testing or harms from the experience. On the other hand, nearly 40% of consumers did not consider the potential for unwanted information from test results, suggesting a need for improved informed consent processes in this context.
Several other publications have resulted from this project:
- Consumers generally understand the key health implications of DTC genetic testing results, although such understanding varies by consumers' levels of numeracy and genetic literacy.2
- Genetic test results are not only of interest in predicting future risk of disease, but also in helping to explain medical conditions that consumers already have.3
- DTC genetic testing may be of special interest to adult adoptees, who often lack information about their family health history within their biological families.4
- DTC testing prompted 27% of PGen participants to discuss their results with their primary care providers, though with varying levels of satisfaction.5
- The likelihood of certain potential harmful responses to testing — such as overutilization of cancer screening tests and medication changes without physician consultation — was very low among study participants.6,7
CTA: Is there strong consumer demand for DTC personal genomic testing for cancer risk?
Dr Roberts: My sense is that there is broad interest, given how many people have relatives who are affected by cancer, as well as the general public fascination with genetics. In our PGen Study, risk information for several cancers was of high interest to consumers. Breast cancer was highest (67% of those surveyed reported being very interested), with strong interest also expressed for risk of prostate, skin, and colon cancers.
The experience of companies like Color Genomics, which offer a lower-cost alternative to traditional hereditary cancer risk assessment conducted in medical centers, may be instructive here in gauging consumer demand for certain types of cancer genetic testing.
CTA: In your opinion, should the FDA allow DTC genomic testing for cancer risks? Do you expect the FDA to approve TC cancer-risk testing?
Dr Roberts: I think the answer depends on many factors: the predictive value of a given test, the quality of education materials provided by the company (including potential access to telephone genetic counseling), and available treatment and prevention options for the disorder in question. I believe the FDA's recent decision does appear to open the door to potential DTC tests in this area.
CTA: One concern about DTC testing is the idea that patients will over-utilize medical resources or seek unnecessary interventions in response to genomic testing results that have unclear clinical implications, such as moderate-penetrance mutations/single-nucleotide polymorphisms (SNPs). Is that concern well-founded, in your opinion?
Dr Roberts: The limited number of studies to date in this area does not suggest a significant increase in unnecessary tests or procedures in response to DTC testing. Studies like ours, however, suggest that around a quarter of consumers share results with their primary care providers (PCPs) and about 5% ultimately seek out a genetic counselor (GC).
I think it could be argued that in many cases, there would be higher priority uses of these providers' time than discussing DTC test results, particularly because PCPs are already pressed for face-to-face time with patients in their busy schedules and GCs are relatively few in number nationwide.
CTA: Should commercial direct-to-consumer cancer gene tests include SNPs that are not yet medically actionable?
Dr Roberts: Again, I think this would depend on the test in question. Our work on Alzheimer's disease (AD) suggests that individuals have many non-medical reasons for wanting genetic risk information, including to inform advance planning decisions such as whether and how much long-term care insurance to purchase. Knowledge of one's genotype could also let consumers know if they would be eligible for the growing number of prevention trials being conducted with adults at high genetic risk for AD and other disorders.7
CTA: The PGen study found that gene test results can increase consumers' use of dietary supplements, apparently in the belief that vitamins or other supplements might reduce disease risk.8 Is that a concern?
Dr Roberts: I think it is somewhat concerning in that people may be wasting their money and/or investing hope in treatments that have not been shown to have any clinical utility. I am less concerned about physical risks to those who use vitamins and dietary supplements, although the supplement industry in the United States has been criticized for a relative lack of regulation and certain supplements are not without risks if taken in excessive amounts.
CTA: PGen did not find that consumers who receive ‘elevated' cancer risk results from personal genomic tests are more likely to seek cancer screening services. Why might that be the case?
Dr Roberts: First, the ‘elevated' risk for most of these tests is not that pronounced, and people are not likely to act upon test results suggesting very modestly increased risk. Second, there are many potential barriers to uptake of cancer screening, including access to care and negative attitudes toward more invasive screening approaches. Finally, recommendations for many screening tests are often based on age, and some consumers may not be in the appropriate age range.
- Roberts JS, Gornick MC, Carere DA, Uhlmann WR, Ruffin MT, Green RC. Direct-to-consumer genetic testing: user motivations, decision making, and perceived utility of results. Publ Health Genomics. 2017 Jan 10. doi: 10.1159/000455006 [Epub ahead of print]
- Ostergren JE, Gornick MC, Carere DA, et al. How well do customers of direct-to-consumer personal genomic testing services comprehend genetic test results? Findings from the Impact of Personal Genomics Study. Publ Health Genomics. 2015;18(4):216-24. doi: 10.1159/000431250
- Meisel SF, Carere DA, Wardle J, et al. Explaining, not just predicting, drives interest in personal genomics. Genome Med. 2015;7(1):74. doi: 10.1186/s13073-015-0188-5
- Baptista NM, Christensen KD, Carere DA, Broadley SA, Roberts JS, Green RC. Adopting genetics: motivations and outcomes of personal genomic testing in adult adoptees. Genet Med. 2016;18(9):924-32. doi: 10.1038/gim.2015.192
- van der Wouden CH, Carere DA, Maitland-van der Zee AH, et al. Consumer perceptions of interactions with primary care providers after direct-to-consumer personal genomic testing. Ann Intern Med. 2016;164(8):513-22. doi: 10.7326/M15-0995
- Carere DA, VanderWeele TJ, Vassy JL, et al. Prescription medication changes following direct-to-consumer personal genomic testing: findings from the Impact of Personal Genomics (PGen) Study. Genet Med. 2016 Sep 22. doi: 10.1038/gim/2016.141 [Epub ahead of print]
- Roberts JS, Christensen KD, Green RC. Using Alzheimer's disease as a model for genetic risk disclosure: implications for personal genomics. Clin Genet. 2011;80(5):407-14. doi: 10.1111/j.1399-0004.2011.01739.x
- Gray SW, Gollust SE, Carere DA, et al. Personal genomic testing for cancer risk: results from the Impact of Personal Genomics Study. J Clin Oncol. 2017;35(6):636-44. doi: 10.1200/JCO.2016.67.1503