Follow the Evidence
Originally published in Memorial University Gazette
Jan. 23, 2019
Faculty of Nursing professor Dr. Anne Kearney was in the final minutes of supervising an exam when she decided to check her email.
Upon reading a message from a friend who sent her a link to a Globe and Mail story, she broke out into a happy dance — at the back of the classroom, where her students wouldn’t notice.
It was news she’d been waiting to hear for more than 15 years: Women don’t need rigid breast screening schedule, stated the headline.
The story reported on a long-awaited report by the Canadian Task Force on Preventive Health Care about the use of mammography as a population-based screening tool for women aged 50-74.
Population-based means that screening is recommended for all women in a targeted age group, not just for women at higher risk.
The big news contained in the report? Clinicians must now engage women in shared decision-making about whether to have mammography screening or not, which acknowledges there is “very low certainty evidence” of effectiveness.
In fact, the task force concluded there is no evidence of mortality reduction overall and good evidence of harm, including over-diagnosis (which results in unnecessary treatment), along with false positives and resulting biopsies.
“I no longer thought the breast screening program was heading in a way that was based on evidence.”
The report’s authors wrote that screening of women aged 50-74 is conditional on primary care providers discussing potential benefits and harms so that women can make an informed decision about whether the benefits outweigh the risks.
That might not sound earth-shattering, but according to Dr. Kearney, who has followed the debate and reviewed the evidence related to the risks of mammography screening for more than 20 years, it’s a significant change.
“There must have been a lively and animated conversation,” she said, noting that the report was almost a full year late. “If something is strongly recommended they would say, ‘We strongly recommend.’ But the screening recommendation is conditional, or weak, which is very important.”
Dr. Kearney described the four main risks associated with mammography screening in a recent Gazette op-ed.
Education lead for breast-screening program
Until the task force published its report in early December, population-based mammography screening had been endorsed by clinicians and stakeholders across the country since the late 1980s.
Dr. Kearney was part of a small group to establish Newfoundland and Labrador’s breast screening program, which launched in 1996. As lead for public and professional education with the program, it was her job to review the most current research on population-based screening.
It was then she began to notice the conflicting reports about effectiveness of mammography screening, the usefulness of clinical breast examination and that breast self-examination was being increasingly questioned by researchers and physicians.
“It was a very confusing time for me,” she said. “I no longer thought the breast screening program was heading in a way that was based on evidence.”
Dr. Kearney began her PhD in 1998, focusing on breast self-examination, because of the conflicting information she was finding. Her work also included a review of mammography screening effectiveness. She completed her PhD in 2004.
And over the past number of years she has presented and written extensively about breast-screening evidence in an effort to change policy.
“We have it all wrong in my opinion: We should not screen all women of a targeted age with mammography; primary care providers should examine women’s breasts; and women should examine their own breasts.”
Dr. Kearney’s mother died of breast cancer at age 53, so she’s quick to point out that she doesn’t “take this issue lightly.”
Along the way there have been small triumphs, such as winning best poster at the 2016 Applied Research in Cancer Control conference held in Toronto, where she was called “brave” for presenting her work at at a time when not all stakeholders appreciated it.
But with the task force now qualifying their recommendation about mammography screening, Dr. Kearney says she feels vindicated.
There’s still much more work to do, she says, including ensuring that women are informed of potential harms and benefits of mammography screening and changing policy to support clinical breast examination and breast self-examination.
The next task force recommendations, she hopes, will unequivocally recommend against population-based mammography screening for women of any age.
“It is a cost-intensive initiative that causes significant harm without evidence of mortality reduction.”
Marcia Porter is a communications advisor with the Faculty of Nursing. She can be reached at firstname.lastname@example.org.