For many years, BR(reast)CA(ncer)1 and BRCA2 were thought to be the only genes in which certain mutations were responsible for this type of hereditary cancer. Researchers now know of other genes responsible for breast, ovarian and the related types of cancer and they will continue to learn more. This means, those who in the past received a negative result for BRCA gene mutations may want to consider being re-tested with a more comprehensive gene panel. In addition, those returning a negative result with a service that is not comprehensive, SUCH AS ANCESTRY DNA SERVICES, may want to revisit genetic testing.
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hereditary cancer genes
As researchers learn more, the percentage of ovarian cancer known to be hereditary is steadily growing. Although not yet a medical recommendation in most regions, many medical professionals suggest that anyone with an ovarian cancer diagnoses receive genetic testing. This is because it may change the treatment course and other family members will need the information to make decisions about their health. Recently, new chemotherapy drugs have been approved or are in clinical trial that are specifically designed for hereditary ovarian cancer.
In Canada, government-insured genetic testing is only available under certain circumstances and, even if one does qualify, it may mean long wait times. As an alternative, Color Genomics, is one of many affordable, quick-turnaround options. Online tests must be ordered by a doctor. If your own doctor is not willing, a reputable service can provide a doctor to facilitate the order.
Make sure genetic counselling is included in the cost, which ranges from $50US if your family already has an identified mutation, to $249US+ for a comprehensive gene panel. Many services also look for additional conditions, so if you do not want that information be sure to mention that when ordering.
Genetic testing is available for persons 18+ years of age and consist of a blood or saliva test. Although genetic testing is available at age 18, in most cases, screening and prevention options are not recommended until the age of 25.
Government-insured genetic testing and follow-up counselling is at no cost for those who already have an identified risky gene mutation in their family, satisfy government family cancer history criteria or have been diagnosed with a suspect cancer. If you do not qualify for government-insured genetic testing or are not comfortable with the wait times in your region, there are private clinic and online alternatives, but make sure you choose a reputable service that includes a full gene panel and genetic counselling. Wait times for genetic test results vary from a matter of weeks to several months, depending on the provider and type of service used.
The wait leading up to genetic testing and for results can be very stressful. Make sure you are supported before, during and after this process. Please contact us and we will put you in touch with someone who has been there. There are many things to think about prior to and after genetic testing. Here are some important considerations.
This type of hereditary cancer is complicated and not always well-understood, even by medical professionals. Prospective risky gene carriers should be well-educated to choose the best option for them because not all genetic tests are created equal. The type of test needed is dependent on the circumstances and on how comprehensive you wish the test to be. Do you want to be tested for all HBOC syndrome risky genes discovered to date? Has a mutation already been identified in your family? Are you of Ashkenazi Jewish decent or of one of the other ethnic groups that experiences a higher rate of risky genes?
Multi-gene panel tests
Panel tests look for mutations across several genes at the same time, giving you a good snapshot of your broader risk for various cancers and health conditions. It is important to know that the multi-gene panel test may identify other cancer risks that weren’t previously on your radar. So, if you don't want that information, that must be conveyed.
Historically, genetic testing focused on examining one gene at a time. If you had a single-gene test that didn’t find a mutation, you may want to ask your healthcare provider or genetic counsellor to order follow-up tests for a different gene (or genes). With the advent of multi-gene panels this process is becoming less frequent.
If you have a family history of a mutation in one gene, a single-site test may be the best option for you. This type of test looks for the specific mutation that’s already been identified. Because it’s only looking for one mutation, this test may be less expensive and have a quicker turnaround. If you are of Ashkenazi Jewish ancestry, a single-site test for the three common founder BRCA1/2 mutations may be especially helpful.
Getting the Right Test
Work closely with your healthcare provider or a genetic counsellor to understand which test is best, given your situation. If you’re uncomfortable with the type of test being suggested to you, keep asking questions and expressing your concerns until you feel satisfied or contact us for more information. Over 1,200 mutations have been discovered to date in each of the BRCA genes alone but some of these mutations do not increase cancer risk so ensure you have a professional genetic counsellor interpret the results.
23andMe released the first consumer-direct BRCA test kit that doesn't require a doctor to facilitate the order. It is important to know the three mutations that can be picked up by this at-home test are just a small fraction of the known gene mutations associated with hereditary breast and ovarian cancer syndrome.
If you do not fit the criteria for government-insured genetic testing, there are affordable, no-barrier options available available through a private clinic or online.
Do your homework to ensure you have chosen the genetic test right for you
Proponents of widespread testing, also known as population testing, believe current guidelines ignore the fact that the genetic predisposition to cancer can be hidden in families. This is because an inherited mutation can be passed down not only by females, but also by males who tend to present with less cancer than females. For this reason, reliance on family medical history may not be enough.
Dr. Mary-Claire King, who first discovered hereditary breast cancer, believes that too many carriers are being missed due to the restrictive criteria for insurance-paid services. This has basis in an increasing body of evidence. Dr. King’s own research reported about 50% of the study group who were diagnosed with breast cancer and were BRCA positive did not have a close family history of cancer. Dr. Steven Narod, world leader in hereditary breast cancer genetics, and his team have tested thousands of women in Ontario, most who do not have a family connection to breast or ovarian cancer. His research has shown that fewer than half of the Jewish women that have been found to carry BRCA mutations would not have qualified for government-insured genetic testing.
Dr. King serves as an unpaid scientific advisor to Color Genomics, an affordable, no-barrier, full-gene-panel service now available in Canada that includes genetic counselling. If you would like to learn more, contact us.