The U.S. Preventive Services Task Force recently recommended lowering the age to begin breast-cancer screenings to 40 years of age from 50. Its report found that screenings every two years from age 40-49 would save 1.3 women per 1,000 screened overall and 1.8 per 1,000 Black women.
“New and more inclusive science about breast cancer in people younger than 50 has enabled us to expand our prior recommendation,” the U.S. Task Force wrote, “and [we] encourage all women to get screened in their 40s.”
Now, regulators in Ontario are recommending women opt-in for preventative screenings beginning at age 40 instead of the province’s current guideline of age 50. British Columbia is also considering this change.
I’m hopeful this new approach can help patients avoid a situation like mine. This month marks the three-year anniversary of my diagnosis with bilateral, Stage 2 breast cancer. After going through major treatments, I’m now on a 10-year regime of adjuvant therapy with my fingers crossed that the cancer won’t re-emerge in metastatic form. I know other women (who, like me, have no known genetic indicators) who were diagnosed with Stage 3 and Stage 4 cancers in their 40s, before they were eligible for screening. I can’t help but wonder if our cancer journeys could have been different with better screening guidelines.
The U.S. report is responding in part to an epidemiological shift. Rates of breast cancer are increasing in women under age 50, an age category that’s also at greater risk of mortality from breast cancer. According to the U.S. Task Force report, the number of invasive breast-cancer cases for 40- to 49-year-old women increased an average of two per cent annually between 2015 and 2019. As the five-year survival for Stage 1 breast cancer is significantly higher than cancers discovered at a later stage, early detection is key to saving lives.
“More health care isn’t always better health care.”
Not everyone in Canada is in favour of changing the screening guidelines. Guylène Thériault of the Canadian Task Force on Preventive Health Care told the Toronto Star her organization is not advising a change in Canada, citing concerns about overdiagnosis causing anxiety and leading to interventions that turn out to be unnecessary. Echoing the overdiagnosis concern, Chris Labos, a cardiologist, wrote in a recent Montreal Gazette Op-ed: “More health care isn’t always better health care. There is a complex balance driven not just by science but also by health-care economics and societal values.”
But Paula Gordon, a Vancouver breast radiologist and professor at the University of British Columbia, has taken issue with concerns about overdiagnosis and patient anxiety. She told the CBC, “If you use that as a reason to not screen, you’re going to miss early cancers you could have found and lives you could have saved.”
How common is overdiagnosis and what are the outcomes? According to a 2022 observational study of more than 900,000 patients screened for breast cancer over a 10-year period, seven to nine per cent were flagged for a biopsy that then proved negative for malignancy.
We can contextualize this number by looking at the FIT colon-cancer test that has a false positive rate of approximately five per cent, requiring further interventions such as colonoscopy. For both colon and breast-cancer screenings, the risks related to a false positive (minor procedures and anxiety – followed by elation) remain low compared with the risks of not having a preventative screening, which include advanced disease and death.
My message to the Canadian Task Force and policymakers is this: Trust women. Trust us to make decisions about our health care. The new U.S. guidance on breast-cancer screening shouldn’t be controversial or a “both sides” issue in Canada. It should serve as a model for the change we need.