Hereditary cancer is a relatively new science. To date, scientists have only discovered a portion of the mutations that cause breast, ovarian and prostate cancer. In the not too distant past, genetic tests only looked for BRCA gene mutations. Today, many additional risky genes have been discovered and more are expected to be discovered. Those with a family history of cancer 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. This also goes for those returning a negative result with today's gene panels who may want to revisit genetic testing in a few years when more genes have been added. As an an example, REQL gene mutations were recently discovered to cause breast cancer, but to date do not show up on most genetic testing panels.
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. An alternative is Color Genomics, a highly reputable service which has a quick-turnaround saliva test. The test can be ordered by your own doctor online or Color will arrange for a doctor to facilitate the test. Genetic testing is included in the cost, which ranges from $50 US if your family already has an identified mutation, to $249 US for a full gene panel, which includes all known HBOC syndrome genes and looks for a variety of other conditions.
Genetic testing is available for persons 18+ years of age, even though screening and prevention options are usually not recommended until at least the age of 25, and consist of a blood or saliva test.
Government-insured genetic tests and follow-up counselling are at no cost to those who already have an identified risky gene mutation in their family, satisfy the family history criteria for their health region or have been diagnosed with a type of cancer that makes them suspect.
Wait times for genetic test results vary from a matter of weeks up to many months, depending on the provider and type of service used. Most government-insured services tend to have longer wait times than pay services.
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.
Regardless of the option you choose, it is essential that a professional genetic counselling session be included.
In March 2017, a Bill was passed that protects individual's genetic information. However, at the time of the last site update, it had still not been put into law. As such, make sure all life and disability insurance is in place prior to considering any genetic testing.
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. If you don't have anyone who can do this for you, 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 someimportant considerations.
Consumers must be well-educated to choose the best fit for them. The first thing to be aware of is that 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 risky genes that have been 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 HBOC syndrome?
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 has focused on examining one gene at a time. If your first single-gene test didn’t find a mutation, your healthcare provider or genetic counsellor may 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 results may come quicker.
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. Some of these mutations do not increase cancer risk. In all cases, it is essential a genetics professional interpret the results.
BEWARE 23andMe recently released the first consumer-direct BRCA test kit that doesn't require a doctor to facilitate the order. It’s important to note the three mutations that can be picked up by the at-home test are just a small fraction of the known BRCA mutations associated with an increased risk for cancer. Over 5,000 different mutations have been discovered to date in just BRCA1 and BRCA2 alone. So although this test may be somewhat useful for people of Ashkenazi Jewish heritage or those who are interested in these particular mutations, it won’t pick up on most BRCA genetic mutations that would increase your risk of breast cancer. Therefore, any result you get from the test—negative or positive—is only a small window into your total genetic cancer risk. Genetic experts have a message for anyone thinking of taking 23andMe's new breast cancer test
If you do not fit the family history criteria for government-insured genetic testing, there are affordable, no-barrier options available that can be ordered through a private clinic or online through your doctor
Do your homework to ensure you have chosen the genetic test that is 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.