May 14, 2013 6:33 pm

Breast cancer and genetics: Angelina Jolie’s double mastectomy

TORONTO – With her star power, Angelina Jolie turned the touchy subject of breast cancer and mastectomies into a household conversation Tuesday.

The Oscar-winning actress announced that she had a preventive double mastectomy. She had tested positive for carrying a gene mutation – called BRCA1 – that significantly increases her risk of breast cancer.

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The gene is a rarity, but if women have the harmful BRCA mutations, it can increase the odds of breast cancer by five times.

In Canada, about one in 250 women carry the BRCA1 or BRCA2 mutation that puts them at an 80 per cent risk of breast cancer, according to Dr. Kelly Metcalfe, a University of Toronto professor and cancer prevention expert.

“It’s significantly elevated compared to the average woman,” Metcalfe told Global News.

A simple blood test could be critical in flagging a heightened risk of breast cancer, experts say. It could lead to proactive action for women and their families.

“Having the knowledge is power. Once you know that you have the mutation and you know you have a certain risk, you can take steps proactively to find things quicker, at an earlier, more treatable stage. Or you can inform your family so they can take steps to protect themselves as well,” Dr. Stephanie Hines, of the Mayo Clinic’s Internal Medicine department, told reporters.

What is the BRCA mutation?

There are two types of BRCA – or breast cancer susceptibility gene. They’re called BRCA1 and BRCA2. The pair are tumour-suppressing genes, according to the National Cancer Institute. They’re meant to stabilize the cell’s DNA and prevent uncontrollable cell growth. But if they mutate, the BRCA genes can lead to breast cancer or ovarian cancer.

How many women have these mutated genes in Canada and how does this increase their risk of cancer?

One in 250 women have the BRCA1 or BRCA2 genes in Canada. The average woman has an 11 per cent risk of breast cancer, Metcalfe said.

But if a woman has one of these harmful genes, their risk increases by 80 per cent. They also face an elevated risk of ovarian cancer. The typical woman has a one per cent risk of ovarian cancer – with BRCA1, that risk jumps to 60 per cent. With BRCA2, the risk is 40 per cent.

“Both men and women can have these mutations, it’s not sex specific for women,” Metcalfe warned.

Are some groups more susceptible to having the genes?

In the general Caucasian population, one in 250 people have BRCA1 or BRCA2. But it’s more common in women of Eastern European Jewish descent. In those cases, one in 50 women have the gene. One study found 2.3 per cent of women in that group had the mutations – that’s about five times higher than in the general population, the Associated Press reported.

Other ethnic groups, including the Norwegian, Dutch and Icelandic people, have slightly higher rates of these mutations.

British Columbia health officials shed light on certain populations who have a higher chance of these gene changes here.

How can you find out if you have the BRCA1 or BRCA2 mutations?

A simple blood test at your doctor’s office can help Canadians detect if they have either mutation. It could take weeks to receive your results, as the blood work is sent to a laboratory.

About three to five per cent of women who develop breast cancer have the mutations, the Centers for Disease Control and Prevention says.

The cost of genetic testing is covered in Canada — if the specific gene mutation is already confirmed in your family.

If not a doctor can refer genetic counselling and testing — and if you meet certain criteria the test will be paid for by provincial health care. If you test positive for the gene and you chose a double mastectomy – the cost of that surgery is covered.

How many women have double mastectomies after learning they carry the genes?

In Canada, about 30 per cent of women with the BRCA1 or 2 genes go on to have double mastectomies, Metcalfe said. She’s conducted international research to see if this is similar in other countries – mastectomies appear to be more common in the United States, but much less popular in Europe.

“We’re not sure why these differences exist, it may be something cultural but it may be also related to the information given to women about cancer risk reduction options,” she said.

Does the cancer risk lessen following a double mastectomy?

Jolie said her risk of getting breast cancer decreased from 87 per cent to five per cent after undergoing a double mastectomy.

Metcalfe said that the risk can be up to five per cent, but “even that is an overestimate.” She said doctors tell women the risk goes down to one per cent.

What other options do women have?

“The decision is very difficult to make, we were hearing this in our clinics all the time,” Metcalfe said.

Right now, women can consider a double mastectomy, but they can also look into breast cancer screenings, from mammograms to MRIs, which can also pick up cancers at very early stages.

“It’s a very personal decision. For some women, they know absolutely what they’re going to do but for most women, it’s a very difficult decision to make,” Metcalfe explained. She even created an aid to help women walk through the decision-making and weigh their options.

She suggests that women look into their reconstructive options, meet with peers who have experienced different options and study photographs of post-mastectomies so they understand what their bodies could look like after.

For more  on the genetic screening test that could detect whether a person has a higher risk of developing breast cancer, watch Laurel Clark’s interview with genetic counsellor Deepti Babu:

- With files from the Associated Press

carmen.chai@globalnews.ca

© Shaw Media, 2013

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