The FDA stresses that despite approving this first-of-its-kind test, the fact is that it only detects three out of 1,000 DNA abnormalities which can lead to cancer, so it shouldn't replace regular mammogram tests or trips to the doctor. For the first time, the agency authorized 23andMe's test for 3 BRCA1/BRCA2 breast cancer mutations, which are most common among Ashkenazi Jews.
According to the National Cancer Institute, the three mutations are present in ~2% of Ashkenazi Jewish women compared to 0 - 0.1% in other populations. "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".
Therefore, you are not completely out of harm's way if you test negative for the 3 mutations. The use of the test carries significant risks if individuals use the test results without consulting a physician or genetic counselor.
The FDA calls the test a "step forward in the availability of DTC genetic tests", but emphasized that there are "a lot of caveats". At MedShadow, she reports on new findings and research on the side effects of prescription drugs.
23andMe founder and CEO Anne Wojcikci acknowledged that most cancer is not hereditary and that this test does not cover many variants tied to an even higher cancer risk. Most cancers are not caused by genetic mutations, and the ones tracked by the test aren't the most common BRCA mutations.
The test should also not be used by consumers or health care providers to decide on any treatments, including anti-hormone therapies and preventive removal of breasts or ovaries. Test results come in the form of a report sent to the user. The test was reviewed through the de novo premarket review pathway. The agency also outlined special controls created to assure test's accuracy and reliability. These special controls, when met along with general controls, provide reasonable assurance of safety and effectiveness for this test.