Using genetic testing to detect ovarian cancer
A letter changed Valerie Stevenson’s life. It also most likely saved it.
In 2012, the 58-year-old Burlington resident’s cousin informed her that the BRCA2 gene mutation was in her family.
According to the Canadian Cancer Society, everybody’s born with BRCA1 and BRCA2 genes. However, specific mutations in these genes increase the risk of developing breast and ovarian cancer.
When she received the letter, Stevenson was caring for her ailing mother. Eighteen months later, she discussed it with her family doctor and then sought genetic counselling at the Juravinski Cancer Centre.
The first step was to test Stevenson’s father. He tested positive for the gene mutation.
“That really hit me because he was never really sick,” she said.
Stevenson, who works at Metroland Media and is the mother of two daughters, then underwent the same simple blood test and discovered she, too, was positive.
“That’s when we started living upside down,” she said. “It was numbing.”
The risk of developing ovarian cancer is as much as 40 per cent for BRCA1 mutation carriers and up to 20 per cent for BRCA2. For breast cancer, it’s about 60 per cent for both.
Kathleen Bell, genetic counsellor and Cancer Risk Assessment Clinic manager, said 20 to 25 per cent of all ovarian cancer cases are hereditary, while five to 10 per cent of breast cancer are.
Gaining information through genetic counselling is the first step for those with BRCA mutations in their families.
“Our job as genetic counsellors is not to force people to have genetic testing,” Bell said.
If a woman has the mutation, she has several options. The most common is removing her ovaries and Fallopian tubes. Though this might sound drastic, there are no good ovarian cancer screening options available. Screening for breast cancer can be done through MRIs or mammograms.
An alarming characteristic of ovarian cancer is its lack of early stage symptoms, Bell said.
“Most ovarian cancer is diagnosed at Stage 3 because there are no obvious symptoms,” she said. “There is a risk if you choose not to have genetic counselling. Having surgery saves lives. There’s good evidence for that.”
Oncologist Dr. Kevin Zbuk said the risk of developing ovarian cancer is reduced by more than 90 per cent with preventive surgery.
“It’s quite dramatic,” he said. “Some (patients) move ahead quickly with surgery and have all the prophylactic surgery they can. Others need more time. But, as they acclimatize to knowing they have this gene mutation, the vast majority have their ovaries removed.”
Zbuk said the children of BRCA mutation carriers have a 50-50 chance of inheriting it. However, if a son or daughter is BRCA negative, the mutation cannot be passed to that child’s child.
“A lot of times we see patients who … get just as involved in genetic testing for their children. They want to do things to help their children down the road,” he said.
After Stevenson received her BRCA mutation diagnosis, she opted to have a partial hysterectomy in October 2014.
“(The pathology reports) came back positive for cancer,” she said. “We didn’t expect that at all. That’s when things really fell apart.”
Stevenson underwent a full hysterectomy in November 2014. Doctors found more cancer, and she embarked on six rounds of chemotherapy in January 2015. In June 2017, Stevenson underwent a double mastectomy to reduce her risk of breast cancer.
No further cancer has been detected. “It’s been a very emotional journey,” Stevenson said. “It’s not just physical. It’s emotional as well. It took a long time to get back on track.”
Stevenson believes the letter was a blessing in disguise because without it, she would not have learned she had cancer until much later.
“Had Valerie not been diagnosed, it’s probably a huge percentage that she would not be living in five years,” said husband Mark, owner of MVR Contracting. “It’s been nearly three years that she’s been clear.”
For the Stevenson family, the question that lingers is: do Stevenson’s daughters have the BRCA mutation?
Victoria, 22, a recent McMaster University graduate, said she and Rachel, 24, will be tested in November.
“I feel it’s something we can handle,” Victoria said. “I feel like it’s a good idea. I’m not hesitant to know.”
Rachel, who works as a remotebased concierge, said she’s pretty optimistic because they’re informed.
“If it’s positive, we have time to have kids before we have our ovaries removed,” she said. “Even if we have the gene (that) doesn’t mean we have cancer. We’re in a better position because most people don’t even know.”
Valerie Stevenson said she was hesitant about her daughters being tested until they were emotionally ready.
“They’re ready and I’m ready. Their positive attitude makes it easier,” she said. “It’s difficult as a parent to think that they might go through this, but I never held my dad accountable at the same time.”