Charity encourages genetic testing to prevent breast cancer, aid research

It's preventative health awareness month, and a Canadian charity is encouraging Ontarians with a family history of breast cancer to get their genes tested for signs they're more likely to develop the disease.

While mammograms are how patients are tested for the presence of breast cancer, genetic testing can reveal whether a person has gene mutations that put them at a higher risk of developing the disease.

These include mutations in the BRCA1 and BRCA 2 genes. People with those gene mutations have up to an 85 per cent chance of developing breast cancer in their lifetime, according to the Canadian Cancer Society.

Breast Cancer Canada CEO Kimberly Carson says women with a family history should get tested so they can take steps to prevent and prepare for breast cancer, like a preventative mastectomy or regular screenings.

"Because we know the earlier we catch it," Carson said, "the better the outcome."

Breast Cancer Canada CEO Kimberly Carson says genetic testing doesn't just help individuals with their treatment, it also helps researchers learn more about hereditary breast cancer. (Submitted by Kimberly Carson)

Genetic testing fuels research

Carson also encourages women with breast cancer to get their genes tested, as that could help researchers better understand hereditary forms of breast cancer.

"So that we have a better idea of what is being genetically passed down and what is not," she said. "You know, what is a hormone response? What is a genetic response?"

More case studies could also fuel research into "which factors are perhaps influencing those breast cancer diagnoses, and trying to treat those patients before it occurs without having to go to the extreme of a double mastectomy," Carson said.

While one in eight women will develop breast cancer in their lifetime, only about five to 10 per cent of cases are hereditary, according to Cancer Care Ontario.

One patient's experience

Melissa Day's family has a history of breast cancer. Before she was diagnosed, she learned she had a gene mutation that put her at a higher risk of getting the disease. She says that knowledge influenced her treatment. (Submitted by Melissa Day)

Melissa Day, 37, was tested for gene mutations in 2019. Her mother is a two-time breast cancer survivor, so she says she always knew there was a chance she was at a higher risk than most.

In early 2020, she discovered she and her mother had a mutation to their ATM gene, which normally repairs DNA. Day says her mother had been genetically tested about 20 years prior, when less was known about the ATM gene mutation, though nothing was flagged at that time.

In 2021, Day was diagnosed with breast cancer. She had a bilateral mastectomy and eventually learned the disease had metastasized.

She says knowing her breast cancer stems from an ATM gene mutation has influenced her treatment. Radiation treatment, for instance, poses a higher risk, she says. Day encourages anyone who can to get their genes tested.

"There's no cure for metastatic breast cancer," she said. "So it's just being on the treatment and hoping that through research, like Breast Cancer Canada does, that we continue to find out more about how the ATM gene mutation will affect future lines of treatment for me."

Not everyone eligible for testing

In Ontario, people with breast cancer, a family history of breast cancer or people who have a family member with a genetic mutation that raises their risk are eligible for genetic testing. Those found to carry those mutations are then counseled on their options and offered regular screenings.

Ontario recently decided to lower the age for regular, publicly funded breast cancer screenings from 50 to 40. That change takes effect in the fall.