Testing for genetic mutations in breast cancers typically only occurs when a patient has a known family history of disease, per US Preventive Services Task Force recommendations.1Yet testing for point mutations in other circumstances — such as when there is a confirmation of the presence of cancer (even in the absence of any family history of disease) or within studies for the purpose of evaluating risk across a specific population — can be useful to identify carriers that may otherwise not know they were at an elevated risk for developing cancer.2,3
That said, there are also some concerns surrounding the democratization of genetic testing, according to authors of viewpoint that was published in JAMA, who were led by hematologist Vinay Prasad, MD, MPH, of the Knight Cancer Institute at the Oregon Health and Science University in Portland.
The first and overarching concern is that the first marketing authorization for such a test, granted to 23andMe by the FDA in March 2018, was for a narrow population. The test looks specifically for mutations in BRCA1 and BRCA2, which are considered to be rare mutations among the general population. The most common mutations associated with breast cancer risk are not identified using the 23andMe test.
In addition, false-positive test results are common for the tests (about 1 in 10 results would be false, wrote Dr Prasad’s team), which could set off a chain of unwarranted medical interventions. Conversely, if family risk of cancer does actually exist, and a patient forgoes clinic-based testing in favor of assessing his or her risk via a DTC test, he or she may be “falsely assured by negative results and not seek genetic counseling.”1 The absence of a BRCA1 or BRCA2 mutation cannot tell consumers if they are “safe” or allow them to rule out cancer risk associated with other mutations.
While overpromotion of genetic tests through ad campaigns or via celebrity endorsements can lead to increased sales for the tests, it can also lead to unnecessary overtesting in low-risk cohorts. And, as Dr Prasad revealed, in the case of BRCA testing, increased testing does not always correlate with increased health services utilization.
- Gill J, Obley AJ, Prasad V. Direct-to-consumer genetic testing: The implications of the US FDA’s First Marketing Authorization for BRCAmutation testing. JAMA. 2018;319(23):2377-2379.
- Hu C, Hart SN, Polley EC et al. Association between inherited germline mutations in cancer predisposition genes and risk of pancreatic cancer.JAMA. 2018;319(23):2401-2409.
- US Food and Drug Administration. FDA authorizes, with special controls, direct-to-consumer test that reports three mutations in the BRCA breast cancer genes. https://www.fda.gov/newsevents/newsroom/pressannouncements/ucm599560.htm. Published March 6, 2018. Accessed June 22, 2018.