It seems like it's never been easier to detect breast cancer. In the past week alone, I've received three press releases touting new technology and tests that promise to make screening either easier, better or more accessible to Canadian women.
The first is a "breakthrough" machine designed to make mammograms more comfortable, thereby encouraging women to have them more often. Then there is a "life saving" ultrasound technology being offered by a Toronto clinic as an alternative to mammograms, described in a press release as being "more thorough and accurate."
At the same time, Toronto's Women's College Hospital announced it is teaming up with a gene-testing company to make screening for BRCA1 and BRCA2 (both linked to a heightened risk of breast and ovarian cancer) available to anyone in Canada, for a fee.
On the surface, these sound like wins for both patients and doctors. New technology or access to more screening is sure to lead to improved detection rates, earlier treatment and fewer deaths.
Not so fast. Compelling evidence shows too much screening can backfire, leading to unnecessary follow-up and treatment for cancers that would likely never pose a health threat. And, in the case of some new forms of breast-screening technology, there is very little credible proof they are actually effective.
An ergonomic mammogram?
GE Healthcare announced this week it's launching Senographe Pristina, a new mammogram machine made with rounded corners and a self-compression tool that lets women adjust the pressure applied to their breasts during exams. The company says this can make mammograms easier, faster and more comfortable, which may encourage more women to get them.
A press release issued by GE references guidelines from the Canadian Association of Radiologists, which state women aged 50 to 74 should get mammograms every year or two. Not enough women are meeting this goal and this new mammogram machine could help bring rates up, the company says.
"It's actually a very unpleasant exam. It's uncomfortable," said Kathleen Schindler, mammography lead for GE Healthcare Canada.
The new machines may make for less painful exams. But the company's emphasis on pushing to increase the number of mammograms performed isn't necessarily a laudable goal. Some experts even say it's counterproductive. According to Canada's national breast-screening guidelines from the Canadian Task Force on Preventive Health Care, average-risk women aged 50 to 74 should get mammograms every two to three years – not yearly, as the radiologists' guidelines suggest.
The Canadian Association of Radiologists has faced criticism from experts such as Cornelia Baines, an expert in breast-screening efficacy at the University of Toronto, for cheerleading too-frequent mammograms, as well as for their financial ties to the makers of some breast-screening machines. (The CAR guidelines also recommend women 40 to 49 undergo yearly mammograms, which is not supported by good scientific evidence.)
"Less would be more and more would be less," Dr. Baines said in reference to the optimal frequency of breast screening.
A comprehensive Cochrane review on mammograms published in 2013 found that for every 2,000 women who get screened over a 10-year period, one will avoid dying of breast cancer. But 10 women who would not have been diagnosed had she not received a mammogram would undergo treatment unnecessarily.
Heather Bryant, vice-president of cancer control at the Canadian Partnership Against Cancer, said the focus shouldn't necessarily be on increasing the number of women who get mammograms, but ensuring that screening programs are targeting the right populations.
"It's making sure that we're targeting those that could benefit, that haven't been reached, and at the same time not exposing women to unnecessary side effects of screening if they wouldn't benefit from it," she said.
The updated machines will be rolled out across the country at a cost of between $250,000 to $275,000, depending on the configuration, to those health-care institutions that want to make the upgrade.
A screening ultrasound?
Toronto's VIP Breast Imaging is promoting its ultrasound screening technology in hopes of making more women aware of the option. According to a company press release, the clinic uses GE Healthcare's automated breast ultrasound system (ABUS) as an "alternative" screening option for women. For $399, women can have a relatively quick, painless ultrasound of their breasts to look for any anomalies, said Amanda Lamanna, director of operations at VIP Breast Imaging.
According to Ms. Lamanna, the ABUS system offers a full screen of the breast and can often detect problems that go missed by mammography. It doesn't use radiation, which means pregnant and breastfeeding women can use it. In fact, she said women of all ages could benefit from this screening method.
"Because it's radiation-free, it's really safe for everyone," she said.
But safe doesn't mean effective. Greg Doyle, chair of the Canadian Breast Cancer Screening Network, said that while ultrasounds have a place in breast screening, they shouldn't be portrayed as an effective screening tool on their own.
"We're not aware of any compelling evidence for the use of that technology for screening purposes," said Mr. Doyle, who is also co-ordinator of Newfoundland and Labrador's breast-screening program.
Anthony Miller, professor emeritus at the Dalla Lana School of Public Health at the University of Toronto, said people are inclined to believe that any test that promises better detection sounds good on the surface. But there are major problems with this approach.
"Increasingly, tests are being used to find small lesions. People feel they have to treat them and then there's the consequences of this treatment," he said. "And yet, a lot of them might never have progressed and caused problems to that woman in her lifetime. That's what we call overdiagnosis."
Population-wide genetic testing
Women's College Hospital is embarking on a new study that will allow anyone in Canada to get tested for the BRCA1 and BRCA2 genes, at a cost of $165 (U.S). Veritas Genetics, a U.S.-based gene testing company, will process the tests and anyone who gets a positive result will hear the news from a representative with the hospital's familiar breast cancer research unit.
One of the goals, said Mohammad Akbari, co-principal investigator of the study and director of the hospital's research molecular genetics laboratory, is to gather enough evidence to persuade governments to relax the eligibility criteria for this type of genetic test. Currently, only those who are seen as having a high risk, such as those with a strong family history of breast cancer, are eligible for publicly funded BRCA screening. He said thousands of Canadian women who carry BRCA mutations are unaware of the fact they face a high risk of breast and ovarian cancer and that expanding gene testing could serve as an early-warning system and push them to take preventive measures, such as a prophylactic mastectomy.
This is an an area that promises to be controversial in the coming months and years, as more gene tests for diseases hit the mainstream. On one hand, there are experts such as Dr. Akbari, who note the health system already pays for cancer-screening tests with major flaws, such as the prostate-specific antigen test. Why not pay for a relatively inexpensive gene test that will, without a doubt, tell an individual whether they are a BRCA mutation carrier?
On the other hand are skeptics like Dr. Miller, who worry this could be another step in the direction of excessive screening and overtreatment. More genetic mutations that are linked to cancer are being discovered all the time. How could the health-care system determine which ones to offer?
Breast cancer is a scary diagnosis, which could help explain why there are so many new tools and gadgets being promoted to detect or prevent it. For instance, there are still plenty of naturopaths and health clinics that offer thermography for breast-cancer screening, despite the fact it has been completely debunked as useless and has been the subject of Health Canada warnings.
Like every other disease, the principles of evidence-based medicine must be applied to breast-cancer detection. And the current evidence shows that average-risk women aged 50 to 74 can benefit from mammograms every two to three years. Consumers would be wise to question the motives of companies that want them to get screened more often, or use alternative methods, than what the current national screening guidelines recommend.
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