Saliva test for gene mutation saves lives
If you or anyone in your family has been diagnosed with breast, ovarian, prostate or pancreatic cancer, I encourage you to get a simple saliva test to determine whether you’re at higher risk for these diseases.
A mutation in genes, called BRCA-1 and BRCA-2, has been linked to these four cancers. You may remember when the actress Angelina Jolie announced she’d had a mastectomy. Jolie’s mother died of ovarian cancer — a major red flag for BRCA — so she wisely got herself tested, and found she had the mutation. Taking preventative measures could very well have saved her life.
As a genetic researcher, I know how scary it can be to undergo this kind of testing. Many people don’t want to live their lives in fear; if they’re at higher risk of cancer, they’d rather not know. But if there’s breast, ovarian, prostate or pancreatic cancer in your family, you likely already live with the fear of getting these diseases.
The stakes are high. Unfortunately, if you’re BRCA positive, your lifetime risk of developing breast cancer is 80 per cent; for ovarian cancer, it’s 40 per cent — and often the disease is not found in the early stages — and for prostate cancer, the risk is 35 to 40 per cent. A BRCA diagnosis also increases the lifetime risk of pancreatic cancer from about 1.6 per cent (in the general population) to about seven per cent.
In all of these cancers, even pancreatic, there are measures you can take to help prevent the disease, or catch it as early as possible. Increasingly, a BRCA diagnosis is being used to customize cancer treatments, especially in pancreatic cancer, where certain types of chemotherapy can be effective in shrinking the tumours of BRCA-positive patients. Similarly, women with breast cancer who have a BRCA mutation would benefit more from a mastectomy (removal of the breast) than a lumpectomy (removing only the cancerous tissue). That’s because these women have a much higher chance of recurrence and of developing a new breast cancer than those who don’t carry the mutation.
And research shows that after about a year, the stress of a BRCA diagnosis goes away. Many patients even feel empowered by the experience, and by the action plan that results from it.
At Women’s College Hospital (WCH), where a lot of our current knowledge about managing BRCA was developed, we’re encouraging all Canadians to get tested for BRCA through an initiative called The Screen Project. Testing technology has become much cheaper in recent years, and we’ve convinced a U.S.-based genetics testing company to offer less expensive rates to our participants. Canadians pay $165 U.S. and receive a simple saliva collection kit by mail. If you have the BRCA mutation, a WCH genetic counsellor will meet with you to discuss an action plan. Participants who can’t afford the fee may be eligible for free testing.
In the first 200 Canadians who enrolled in the study, we found six BRCA carriers. Half of them would have qualified for the health-care system covered testing due to family history, but they preferred not to wait (there can be long waits under OHIP because of the shortage of genetic counselling, which always goes with the tests). The other three people would not have qualified for testing under the health system because there was no indication that they were at risk for the BRCA mutation. And yet they had it.
Even if you don’t have a family history of the four cancers, you might consider BRCA testing since there is still a chance to carry a mutation without a family history, especially in small size families. In the Caucasian population, it is estimated that one in 200 people carry the mutation. But among the Ashkenazi (Jews of European background), there’s a carrier for every 40 people.
To know or not to know — this is going to be an increasingly complex question as scientists develop more ways to peer into our genes and predict our medical future. In considering this question, I always ask whether the information is “actionable” right here and now. In the case of BRCA, it’s clear that we can use a positive finding to better prevent and treat four types of cancer — two of them very common, and at least two of them quite deadly. I think the benefits to knowing are substantial — and in some cases, life-saving.
Dr. Mohammad R. Akbari is an assistant professor in Dalla Lana School of Public Health and the Institute of Medical Sciences at U of T’s Faculty of Medicine. He is also a Scientist at the Women’s College Research Institute. Doctors’ Notes is a weekly column by members of the U of T Faculty of Medicine. Email .