FDA has granted marketing authorization for the genetic health risk (GHR) report on select variants in the BRCA1 and BRCA2 breast cancer genes, from the personal genome service of 23andMe, Mountain View, Calif.
The direct-to-consumer (DTC) test is the first to report on three specific BRCA1 and BRCA2 breast cancer gene mutations that are most common among people of Ashkenazi (Eastern European) Jewish descent. However, the three mutations are not the most common BRCA1/BRCA2 mutations in the general population.
The test analyzes DNA from a self-collected saliva sample, and the report describes whether a woman is at increased risk of developing breast or ovarian cancer, or if a man is at increased risk of developing breast cancer or may be at increased risk of developing prostate cancer. The test only detects three out of more than 1,000 known BRCA mutations. This means a negative result does not rule out the possibility that an individual carries other BRCA mutations that increase cancer risk.
“This test provides information to certain individuals who may be at increased breast, ovarian, or prostate cancer risk, and who might not otherwise get genetic screening, and is a step forward in the availability of DTC genetic tests. But it has a lot of caveats,” says Donald St. Pierre, acting director of the Office of In Vitro Diagnostics and Radiological Health in FDA’s Center for Devices and Radiological Health.
“While the detection of a BRCA mutation on this test does indicate an increased risk, only a small percentage of Americans carry one of these three mutations, and most BRCA mutations that increase an individual’s risk are not detected by this test,” says St. Pierre. “The test should not be used as a substitute for seeing your doctor for cancer screenings or counseling on genetic and lifestyle factors that can increase or decrease cancer risk.”
Consumers and healthcare professionals should not use the test results to determine any treatments, including antihormone therapies or prophylactic removal of the breasts or ovaries. Such decisions require confirmatory testing and genetic counseling. The test also does not provide information about a person’s overall risk of developing any type of cancer. Use of the test carries significant risks if individuals use its results without consulting a physician or genetic counselor.
According to a National Cancer Institute study, the three BRCA1/BRCA2 hereditary mutations detected by the test are present in about 2% of Ashkenazi Jewish women, but rarely occur (0% to 0.1%) in other ethnic populations.1All individuals, whether they are of Ashkenazi Jewish descent or not, may have other mutations in BRCA1 or BRCA2 genes, or other cancer-related gene mutations, that are not detected by this test. For this reason, a negative test result could still mean that a person has an increased risk of cancer due to gene mutations.
Additionally, most cases of cancer are not caused by hereditary gene mutations but are thought to be caused by a wide variety of factors, including hormone use, obesity, smoking, and other lifestyle issues. For all of these reasons, it is important for patients to consult their healthcare professional, who can help them understand how these factors affect their individual cancer risk and what they can do to modify that risk.
FDA’s review of the test determined that the company provided sufficient data to show that the test is accurate (ie, can correctly identify the three genetic variants in saliva samples), and can provide reproducible results. Using representative GHR test reports, the company submitted data from user comprehension studies which showed that the test’s instructions and reports were generally easy to follow and understood by a consumer. The test report provides information describing what the results might mean, how to interpret results, and where additional information about the results can be found.
FDA reviewed data for the test through the de novo premarket review pathway, a regulatory pathway for novel low- to moderate-risk devices that are not substantially equivalent to an already legally marketed device. Along with its authorization of the test, FDA established special controls that set forth the agency’s expectations for ensuring the test’s accuracy, clinical performance, labeling, and reproducibility. Together with general controls, the special controls imposed by the agency provide reasonable assurance of safety and effectiveness for the test.
REFERENCE
- Struewing JP, Hartge P, Wacholder S, et al. The risk of cancer associated with specific mutations of BRCA1 and BRCA2 among Ashkenazi Jews. N Engl J Med. 1997;336(20):1401–1408.
