Your genetic counselor and/or physician will work with you to help you decide on a genetic testing option. If you don’t have access to a genetic counselor in your area, try to schedule a counseling session over the phone or online. Two potential resources are the National Society of Genetic Counselors and Informed DNA. You can check with your insurance plan to see if it covers this type of appointment.
The following factors often play a role in deciding on the most appropriate test:
If another family member(s) has tested positive for a mutation in one area of a specific gene, then usually you would be tested for the same mutation.
Your genetic counselor can order a test that looks for the very same area of abnormality that has been found in your relative(s) and is linked to the breast cancer in your family. Typically this involves looking for mutations in the BRCA1 or BRCA2 gene, but it might involve another one of the genes identified more recently. If there are family members with mutations affecting different locations in the same gene, testing would look at all of these areas.
“A mutation is essentially an ‘address’ that tells you exactly where in the gene that mutation lies,” explains Cristina Nixon, M.S., LCGC, a licensed certified genetic counselor with the Cancer Risk Assessment and Genetics Program at Main Line Health in Pennsylvania. “For example, a mutation in BRCA2 such as ‘5073dupA’: the combination of numbers and letters tells the testing lab precisely where to look. If your relatives have this mutation, this is what your genetic counselor would put on the order form.”
In some cases, a person may need to be tested for more than one mutation. If you have a family history of cancer on both sides (your mother’s and father’s) that suggests additional genetic mutations could be present, you might consider a panel test that includes more genes. Also, some insurance plans will only cover genetic testing once in your lifetime (“one and done”). If cost is an issue and you’re concerned about the possibility of other cancer-related genetic mutations, then you might want to see if your plan will cover panel testing.
If a breast cancer-related mutation hasn’t yet been identified in your family, you and your genetic counselor will decide which genetic tests make sense for you.
At minimum, for most people, BRCA1 and BRCA2 testing will be ordered. “With some labs, you can add in testing for other genes that are considered high-risk, such as PALB2, p53, and PTEN, among others,” explains Cristina Nixon. “However, you sometimes can expand it further to include moderate-risk gene mutations, and then maybe expand it even further to include those where we don't know as much about what the risks from mutations are. They’re relatively new, so the trouble with adding them in is that sometimes we don’t know what to do when there’s a mutation found in one of those genes. These are all important factors to consider.”
Whether or not you add more genetic tests to the panel can depend on other factors, such as:
- The pattern of cancers in your family, including what types and at what ages family members were diagnosed. If the pattern suggests a BRCA1 or BRCA2 mutation, you might start there. Or, if there are other types of cancer occurring frequently, it may be recommended to add tests for other gene mutations. The same is true if your family history is incomplete or unknown, whether due to missing medical records, loss of a parent, closed adoption, etc.
- Your preferences about what you do or don’t want to know about your cancer risk(s). All of the genetic mutations that increase breast cancer risk also put you at increased risk for other forms of cancer. Also, there are some genes with higher-than-average breast cancer risks, but no published guideline to recommend high-risk screening or prevention if a mutation is present because the data on breast cancer risk is unclear. If you don’t want this information, or you don’t think you would act on it, then a panel test that includes many genes may not be right for you.
- Insurance coverage. Insurance plans vary. Some won’t cover panel testing for multiple genes unless: (1) there is strong evidence you’re at risk of having a mutation in more than one gene, or (2) clear action steps can be taken to reduce risk if you test positive. Also, some insurance plans might only cover genetic testing once in your lifetime, so it’s important to consider your options carefully.
- The testing company your hospital uses and/or that is included in your insurance network. Myriad, GeneDx, Ambry, and LabCorp are just some of the many companies that offer genetic testing. Some companies offer the option of choosing which genes you want included in a panel test. Others only offer pre-set panels (certain genes have to be tested as a group). If your insurance coverage limits you to testing by a certain company, this might affect your choices.
- Past genetic test results. If you had BRCA testing in the past and results were negative for you and your relatives, but your family history of breast cancer (and possibly other cancers) is strong, you might consider panel testing to see if another genetic mutation might be the cause. (NOTE: If you had a BRCA1 or BRCA2 test before 2006 and tested negative, you might want to consider testing again since the technology has changed. Now, tests are able to detect mutations involving a larger area of each gene [e.g. large deletions, duplications, or rearrangements]. Before 2006, tests could only look for gene mutations smaller in size.)
Making these decisions is complicated. Genetic counselors are trained to help you make the best decision for your situation.