Affordable genetic testing is now widely available in Canada. As patients take a more proactive role in the management of their own health care, many are considering genetic testing offered by companies such as 23andMe and AncestryDNA, to name but a few. As a Jewish community, we should welcome such advances in health care and approach it with guided optimism.
Most breast cancers diagnosed in women are not associated with a hereditary predisposition. However, the occurrence of recurrent, or “founder,” mutations, which significantly increases one’s risk of developing breast and ovarian cancer, is more pronounced in Jews of Ashkenazic (central or eastern European) descent.
In the Jewish community, three mutations occur with increased frequency: 187delAG and 5385insC in BRCA1 and 617delT in BRCA2. In the general population, the frequency of BRCA1/2 mutations is around one in 1,250; in Ashkenazic Jews, it’s one in 77. For people who have a mutation in BRCA1 or BRCA2, their risk of developing breast cancer is 50-75 per cent, depending on a number of other factors, and 33-54 per cent, respectively. With regards to ovarian cancer, the risk is 22-51 per cent for BRCA1 and four to 21 per cent for BRCA2. The risk of developing other forms of cancer – including colon, prostate and pancreatic cancer – also exist, but are much lower.
As a surgical oncologist and a member of the Toronto Jewish community, I have seen the devastating effects that a diagnosis of breast or ovarian cancer can have on women and their families, and the lasting scars it leaves on future generations. Finding out if one is a carrier of BRCA1/2 with a simple saliva test is a powerful piece of knowledge that generations that preceded us weren’t afforded.
There are also ways of mitigating the risks of developing some of these cancers. For example, women who are carriers would be eligible to have their annual mammogram augmented with a breast MRI. This added tool would allow for even earlier detection of breast cancer, which could be treated at an earlier stage.
Prophylactic mastectomies with reconstruction is also a very effective means of prevention and can reduce one’s risk of developing breast cancer to less than two per cent. Risk reducing bilateral salpingo-oophorectomy (Fallopian tubes and ovaries) is strongly recommended for mutation carriers who are done having children and are more than 35 years old.
READ: THE DARK SIDE OF DNA TESTING
So what are the down sides of testing? In the short term, the impact of genetic testing has demonstrated a substantial decrease in distress and anxiety among women who learn that they do not carry one of these mutations. However, women who receive a positive test result may experience increased distress and anxiety immediately following the result. Despite these short-term differences, there is no evidence to suggest that these women suffer from increased distress, anxiety or depression over the long term.
A historic barrier to genetic testing has been the fear of discrimination based on the results. Yet in 2017, the federal government passed the Genetic Non-Discrimination Act, which prohibits the use of genetic test results in areas outside of medical care, such as insurance and employment.
I advise patients with a family history of breast or ovarian cancer to get tested, especially Jewish patients (even if they aren’t Ashkenazic). Even if it was a single relative who had breast or ovarian cancer, the mutation could be passed down through males, as well as females, and may not be as obvious in a family with lots of men.
The results of such tests should be discussed with a health-care professional who’s trained in genetics and a personalized preventative care plan should be developed. Regardless of one’s gender or age, the power of this information could alter the course of their lives and the lives of their children, and that is truly a blessing.