The revelation that Hollywood celebrity Angelina Jolie had a double mastectomy as a preventative measure against cancer stoked heated discussion this week, but one prominent cancer researcher says it demonstrates the need to make genetic testing available to all Canadians.

The actor and humanitarian wrote an opinion column in the New York Times on Tuesday in which she revealed that she had had a preventative double mastectomy in February.

Jolie said a genetic test revealed she had a "faulty gene," BRCA1, like her mother, who died of cancer at the age of 56.

Based on the test, doctors estimated Jolie had an 87 per cent risk of breast cancer and a 50 per cent risk of ovarian cancer, which is why she said she opted for the procedure.

Dr. Steven Narod, a senior scientist at Women’s College Hospital in Toronto, has followed the debate about the article, but says that in scrutinizing Jolie’s decision, pundits and readers are missing a broader lesson about access to genetic testing.

"I heard so many dumb opinions over the last couple of days, [but] no one asks: why aren’t we efficiently offering this to Canadians?" says Narod, who believes that people should have equal access to genetic tests.

Looking for mutations

Genetic testing is meant to identify people who have an increased risk of getting cancer by looking for mutations in genes on a chromosome. In the case of Jolie, it was a test that looked specifically for the BRCA mutation.

Anyone can get a genetic test, but it is quite expensive — private clinics in the U.S. will do it for about $3,000 to $4,000. In Canada, provincial governments will cover the cost of the test, but only if the individual meets specific criteria.

There are nuances in the criteria from province to province, but the main requirement is that you can demonstrate that two of your blood relatives have had breast or ovarian cancer.

Narod says that the current criteria are too restrictive.

"If you have to get two cases of cancer in the family to qualify for testing, you’re only going to prevent the third [cancer]. We should be preventing the first one," says Narod.

Most cases ‘sporadic’

According to the American Cancer Society, only about five to 10 per cent of all cancers are inherited. Most cancers develop as a result of lifestyle choices (such as smoking) or environmental factors.

Approximately 90 per cent of breast and ovarian cancer cases are considered "sporadic," meaning there’s no family history of cancer and it is not associated with a BRCA mutation, says Barbara Vanderhyden, a senior scientist at the Ottawa Hospital Research Institute who focuses on ovarian cancer research.

Angelina Jolie announced on May 14 that she had had a preventative double mastectomy. (Carlo Allegri/Associated Press)

As a result, the BRCA test provides a good picture of a person’s risk of developing breast or ovarian cancer, but only for a small percentage of women, says Vanderhyden.

"For women without a family history, there really isn’t any reason to go through the potential trauma of having the genetic testing if the likelihood is so low that a mutation is actually present," she says.

She adds that the criteria in her home province, Ontario, "tries to capture everyone who might be at significant risk of developing breast or ovarian cancer."

The Canadian Cancer Society says on its website that genetic testing "only provides a piece of information about a person’s health. Other genetic and environmental factors and lifestyle choices affect a person’s risk of developing cancer."

The organization goes on to say that genetic testing "is most useful when it is done in a family member with cancer who also has a family history that suggests a particular hereditary cancer syndrome."

In the New York Times piece, Jolie herself acknowledged that "only a fraction of breast cancers result from an inherited gene mutation."

Mutations in specific populations

While her story transfixed people the world over, Narod says Jolie’s case has particular relevance to Canadians because her mother, Marcheline Bertrand, was French-Canadian.

Over the course of his research into breast and ovarian cancer, Narod has identified mutations in a number of specific ethnic populations, including people of French-Canadian, Bahamian and Ashkenazi Jewish descent.

If genetic tests were made affordable and available to everybody, rather than just to those with a family history of cancer, more people would have a better idea of their risk of developing cancer, says Narod.

"There are hundreds of women in Quebec who have [the BRCA] mutation and are walking around with it. We should be doing everything in our power to identify them to give them the options" for dealing with it, Narod says.