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Illness prevention and treatment

October 13, 2017

What’s new in genetic testing for breast cancer

Call it the Angelina Jolie effect – the result of the actor’s high-profile response to hereditary breast cancer. Here’s the latest on genetic testing.

In 2013, actor Angelina Jolie wrote an op-ed in the New York Times on her choice to get a double mastectomy. Jolie revealed that she carried a mutated gene that put her risk of breast cancer at 87%. Jolie’s mother had died a few years earlier from breast cancer, so when she tested positive for the faulty gene, she decided to have the surgery to prevent the disease from developing.

Jolie’s article went viral and sparked an ongoing conversation on genetic testing. In 2016, researchers at Harvard University found a spike in the number of women having genetic tests since Jolie wrote her article. They call it “the Angelina Jolie effect.”

Researchers first discovered how BRCA1 and BRCA2 gene mutations affect the likelihood of some cancers in the 1990s. The initially very high cost of genetic testing has decreased since then, but access to genetic screening for breast cancer can still be challenging for most Canadians, says Dr. Mohammad Akbari. He’s a scientist working at the Women’s College Research Institute in Toronto on a study called the Screen Project. The project team, affiliated with the University of Toronto, is researching the benefits for Canadians of more widely available genetic testing for breast, ovarian, pancreatic and prostate cancers.

Women at high risk for breast cancer may have genetic testing paid for by their provincial health insurance according to eligibility guidelines established by their provincial ministries of health (largely based on maternal family history). But wait times for province-paid genetic testing vary, and can be as long as 2 years. Women who don’t fall within the guidelines or who don’t want to wait may seek screening through a private clinic or other lab, but such testing is only available in some parts of the country, and the out-of-pocket cost through most private labs in Canada starts at around $600.

The Screen Project makes testing for mutated BCRA genes more accessible than it would normally be. If you’re interested in having genetic testing, you can fill out an online survey to join the study. Study participants will receive a kit to collect a saliva sample at home; they then send the sample to a lab at Veritas Genetics to be tested, and the results come back in about 2 to 4 weeks. The test costs $165 USD ($203CAD as of Sept 26, 2017) and the study is slated to run for the next 3 years.

What are BRCA1 and BRCA2 genes and how do they affect your cancer risk?

Only 5 to 10% of breast cancers are caused by inherited or genetic factors, including (but not only) faulty BRCA genes, according to the Canadian Breast Cancer Foundation. The chance of having a BRCA1/2 mutation is low for people without a personal or familial history of breast, ovarian, fallopian tube or primary peritoneal cancer.

However, women who have inherited a flawed BCRA1 or BCRA2 gene have a very high risk of developing cancer over their lifetimes. Women in the general population have about a 12% risk of developing breast cancer, according to Veritas. A BRCA mutation raises that risk to as much as 80%.  Similarly, a BRCA 1 or 2 mutation can increase a woman’s lifetime risk of ovarian cancer from 1.3% to 40%.

BRCA1/2 genes create tumor suppressor proteins that repair damaged DNA. But if either of these genes are mutated or flawed, damaged DNA may not get fixed, and cells may develop genetic alterations that result in cancer. People with BRCA 1/2 mutations are not only more likely overall to develop cancer, but also tend to develop it at a younger age and in some cases tend to have more aggressive tumours than the general population.

Who should have genetic testing?

According to Dr. Akbari, there are many reasons to consider genetic testing. Most critically, patients who have been diagnosed with breast, ovarian, pancreas and prostate cancer should be tested, because a mutated BRCA 1/2 gene will affect the treatment plan for their cancer. “If somebody carries that mutation, the best care option may be a mastectomy rather than a lumpectomy, because the chance for that patient to have a recurrence or a new primary cancer is much higher than a patient with no mutation,” says Akbari.

If you haven’t been diagnosed with cancer but you have a family history of breast, ovarian, pancreatic or prostate cancer on either your father’s or mother’s side, you should also consider being tested, says Akbari. Research shows the more relatives you have with a history of cancer and the younger they are when they’re diagnosed, the more likely you are to have a mutation. Research has also shown that people of certain ethnic groups, such as Ashkenazi Jews and Bahamians, have a higher mutation frequency rate.

In fact, all Canadians over 18, “particularly mature women,” should consider being tested, says Akbari. Breast cancer strikes women most often between the ages of 50 and 74, but carriers of BRCA mutations could be diagnosed with a cancer as early as their 30s.

What if I test positive for a mutated BRCA gene?

If you test negative for gene mutations, you will be notified by mail, but if you test positive, you will get a call from a genetic counsellor. “Through the study, participants receive genetic counselling after the test,” says Akbari. “We want to make sure they have all the information they need to make an informed decision about their treatment.”

Study participants in the Greater Toronto Area (GTA) can choose to receive genetic counselling at the Women’s College Hospital, while those living elsewhere are referred to a local cancer care centre. “People who are known carriers of a mutated BCRA1/2 gene will likely get expedited genetic counselling from their local cancer care centre,” says Akbari. However, the wait could still be a few months, he says.

As a next step in cancer prevention and treatment, carriers of the mutated gene may undergo intensive MRI screening. As a preventative measure, they may then choose to go the same route as Jolie and have  their ovaries and/or their breasts removed. Ultimately, their next steps depend on important personal considerations, including their age and whether they have already had or wish to have children, as well as their doctors’ recommendations.

Lowering your risk of breast cancer through lifestyle choices

The causes of breast cancer are various and complex, and while your heredity is beyond your control, you can make lifestyle choices to decrease your risk of getting the disease, says Akbrai.

  1. Get lots of exercise.
  2. Drink in moderation.
  3. Avoid tobacco.
  4. Watch your weight. Being overweight, especially during menopause, can increase your risk of cancer.

The Screen Project aims to make it easier for Canadians to get genetic testing for breast cancer, but it’s important to understand the limitations and consequences of this testing. Knowing you carry a mutated gene could make you anxious, sad or afraid. It also means you may have to make some hard decisions about surgery.

“Knowing you’re a carrier of a faulty BCRA gene may give you some anxiety,” says Akbari. “Our research has found, though, that after a year, people accept the reality of their situation and feel better knowing they can take preventative action.”

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