Genetic Tests Showing Small Cancer Risk Do Not Change Behavior
December 13, 2016 | by Katie Neith
Swabbing the inside of your mouth and sending a saliva sample through the mail for genetic analysis is one of the easiest and least invasive ways to test for a multitude of health risks.
But since the advent of direct-to-consumer (DTC) genetic testing for medical purposes, the industry has been fraught with controversy, with the Food and Drug Administration (FDA) effectively halting the release of risk-specific genetic information in 2013. Which is why City of Hope researcher Stacy Gray, M.D., associate clinical professor of clinical cancer genomics in the Department of Population Sciences, aims to gain a deeper understanding of the pros and cons that DTC genetic testing can offer both consumers and the health care industry.
A paper outlining Gray’s latest work — which looked at consumers who received DTC genetic testing that revealed an elevated cancer risk — was published in the Dec. 12 issue of the Journal of Clinical Oncology. She led a study that followed 762 new customers who received cancer-related health data from either 23andMe or Pathway Genomics. The study was done prior to the FDA ruling that halted such companies from releasing health-related data via DTC genetic testing.
“Our paper is a very interesting and timely piece because the FDA is actively trying to grapple with how to regulate this industry,” said Gray, who joined City of Hope from the Dana-Farber Cancer Institute in August 2016. “There are few data that document the benefits and harms of direct-to-consumer access to genomic technologies, so studies like this are needed.”
Too Much Information?
One of the big worries about DTC testing, Gray said, is that people who receive data suggesting an elevated risk for cancer may rush out and overutilize screening tests, overwhelming an already strained health care industry. But the study showed that such fears were not likely to be warranted.
“In this population of people who are already engaged in personal genomic testing online, we did not see evidence of overutilization of cancer screening tests including mammography, colonoscopy or prostate-specific antigen (PSA) testing,” said Gray. “One of the reasons we might not have seen an increase in utilization among those who tested and were at an increased genetic risk as determined by the company is that the people in our study were already largely compliant with cancer screening recommendations. At the same time, these findings are reassuring because we have evidence that people are not having even more testing as a result of direct-to-consumer genetic testing.”
At the same time, Gray and her team also did not find a correlation between elevated cancer-risk results and positive behavior changes, such as diet adjustments, increased exercise or advanced care planning.
“The one exception to that is that men who were told that they were at an elevated genetic risk for prostate cancer significantly changed their use of vitamins and supplements,” Gray pointed out. “That’s one area where we want to conduct more research because use of some types of supplements has been associated with the development of prostate cancer. So the question now is whether their change in behavior was one that was positive or whether it could have negative health consequences.”
Accessing Your Own Blueprints
Gray said it’s important to note that the study involved changes in risk level that were fairly low (not like the high levels of risk seen with BRCA mutations), which may account for the lack of significant change in health behaviors. In addition, researchers aren’t sure how consumers are interpreting health information when they receive it online versus through a physician or other health care provider. She also said that since the study examined a population of people who were already engaged in genetic testing, the results cannot be applied to everyone in the general population.
“What people who are less engaged with health will do with DTC personal genomic information is very difficult to predict,” said Gray. “At the same time, finding that there wasn’t overutilization of medical testing is reassuring. Furthermore, finding that direct access to genetics can be a way for people to engage in genomics — without evidence of harm — is something that is very promising.”
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