BRCA1 and BRCA2 versus Panel Testing
Changes in the BRCA1 and BRCA2 have been known to have a link to hereditary breast cancer since the 1990s. Research in recent years has uncovered that there are several more genes that can increase the risk in a family. How much the risk for breast cancer is increased depends on which gene is found to have a change (or a mutation), and a patient’s family history.
Genetic testing for BRCA1 and BRCA2 has been available to patients since the mid-1990s, so most insurances will cover testing for these genes as long as a patient meets the established criteria. Established criteria is determined by the medical board of each separate insurance provider, but most generally follow recommendations from professional medical organizations, such as the National Comprehensive Cancer Network (NCCN). These guidelines look at a patient’s personal and family history of cancer to try to determine who is at the highest chance to benefit from the genetic testing. In other words, which patients look the most suspicious for actually having a change in BRCA1 or BRCA2 based on how their medical and family history looks?
If a patient meets their insurance’s criteria to qualify for genetic testing for BRCA1 and BRCA2, generally insurances will cover this testing with little to no out-of-pocket cost to the patient. Because genes other than BRCA1 and BRCA2 are more recent discoveries, a lot of insurances consider them investigational and will not cover testing for them (even though NCCN has some recommendations for different screening for some of these genes).
If you had negative BRCA1 and BRCA2 testing, or couldn’t get insurance to cover genetic testing at all, it could be beneficial to meet with a genetic counselor that can look at your medical and family history to determine the likelihood that genetic testing will be beneficial for you. In cases where your insurance will not cover testing, or even if you may not necessarily meet traditional criteria to get testing, and you are still motivated to do this type of testing, there are affordable options that your genetic counselor can review with you.
One important difference to note between testing just for BRCA1 and BRCA2 versus panel testing is the chance for uncertain results. When doing genetic testing of this nature, there are three possible results we can get: negative, positive, or uncertain (also called a variant). A negative result means that the lab did not find any harmful changes that increase the risk for cancer in any of the genes they looked at. A positive result means that the lab found a harmful change in a gene that increases the risk for cancer. An uncertain result, or variant, means that the lab found a change in the gene but they have not seen it enough to know whether it is harmful or not.
Because we have been studying BRCA1 and BRCA2 for many years, we are more familiar with them, and the chance to get an uncertain result is generally thought to be less than 5-10%, but this greatly depends on which lab you use. When a panel test is done that looks at many more genes that we have not been studying for as long, the chance to get an uncertain result can be as high as 1 in 3 (33%).
When the lab gets an uncertain result, they continue to try to gather information about that specific change to try to find out if it is harmful or not. Sometimes they can get that answer in weeks or months, often it can take years. The vast majority of the time, the lab ends up finding out the variant was not harmful, or does not increase the risk for cancer. If someone has a variant on their genetic testing result, we default to looking at their medical and family history to determine what kind of cancer screening we would recommend.
Testing for a familial gene mutation (Single Site Testing)
BRCA1 and BRCA2 or panel testing can be used to help try to figure out what the cause of cancer is in the family. Single site testing is done when a harmful gene change that increases the risk for cancer has already been found in a family. Once the specific change has been identified, we can start to offer testing to people in the family who have not yet had cancer to determine whether they also inherited this gene mutation (and share the increased risk for cancer), or whether they did not inherit the gene mutation (and have the same risk for cancer as the general population). Once we determine who is at an increased risk for cancer in the family, we can discuss methods of early detection or prevention to help keep everyone healthy.
For more information on genetic testing for hereditary cancer predisposition, please see How Does Genetic Testing for Cancer Work?