Key message
Self-reported mammography rates vary from the low-60%s to the mid-70%s across provinces and territories.
Indicator definition
The percentage of women aged 50–69 who reported being up to date on breast cancer screening, defined as having had a mammogram for any reason in the previous two years. Results are presented by province/territory using data from the 2012 Canadian Community Health Survey.
Target
There is no target for overall mammography rates (mammography for any reason). The Canadian Breast Cancer Screening Network’s programmatic screening participation target (70% of average-risk women participating in breast cancer screening) has been applied to overall mammography rates in this report to provide context for an approximation of how much of the population should be undergoing mammography. The target was applied to system performance reporting as of 2015.
Measured since
The 2009 Cancer System Performance Report.
This indicator definition was revised in 2016 to report on mammograms done for any reason, rather than mammograms done only in asymptomatic women.
Why measure this?
Breast cancer screening guidelines from the Canadian Task Force on Preventive Health Care recommend that women aged 50–69 years at average risk for breast cancer be routinely screened using mammography every two to three years,1 balancing the mortality benefits that result from screening with the harms that can be associated with it (e.g., false positives, over-diagnosis).
Monitoring and reporting on mammograms performed for any reason (rather than only those done for asymptomatic reasons) provides a snapshot of the proportion of women who have had the test that identifies breast cancer within the recommended screening interval, enabling assessment of population-level breast cancer risk. Mammograms for any reason were included because women who have diagnostic mammograms are ineligible for screening in several programs but are still considered to be protected from a population-level risk perspective.
What are the key findings?
- Rates of self-reported mammography (done for any reason) for women aged 50–69 ranged from 61.0% in Prince Edward Island and Yukon to 74.0% in Quebec in 2012 (Figure 2.2).
- Of the 13 reporting provinces/territories, six (Alberta, Manitoba, Ontario, Quebec, New Brunswick and Newfoundland and Labrador) had mammography rates that exceeded the 70% participation target in 2012 (Figure 2.2). When taking into account statistical margin of error, only Saskatchewan did not reach the target.
- Rates for mammograms done for any reason were within 0.6 to 3.6 percentage points of rates for mammograms done on asymptomatic women only (data not shown; see the 2015 Cancer System Performance Report for information on screening in asymptomatic women).
Why do these findings matter?
Self-reported mammography rates were generally high across the country, though some variation did exist. Women can access mammography in multiple ways, which may contribute to some of the observed variation. Asymptomatic women can access screening mammography through organized breast cancer screening programs, which exist in all provinces and territories except Nunavut.2 All women can also access mammography opportunistically (e.g., by self-referral or through physician referral for a screening appointment at a hospital or physician’s office)3 for any reason.
The screening participation target is being compared with self-reported mammography rates for the purposes of system performance reporting, which includes all mammograms conducted for any reason (unlike the program target, which includes only programmatic screening activity). Monitoring mammography rates at the system level facilitates evaluation of practices across the country to determine what proportion of the population is protected against this screenable cancer at a given time. Monitoring helps to identify interventions that will increase the proportion of the population protected and receiving treatment when it is most effective—for instance, by targeting low-income or immigrant women.
References
- Canadian Task Force on Preventive Health Care, Tonelli M, Gorber SC, Joffres M, Dickinson J, Singh H, et al. Recommendations on screening for breast cancer in average-risk women aged 40-74 years. CMAJ. 2011 Nov 22;183(17):1991-2001.
- Cancerview.ca. Breast Cancer Screening Guidelines Across Canada: Environmental Scan. Toronto (ON): Canadian Partnership Against Cancer; 2015 Jul.
- Canadian Partnership Against Cancer. Cancer Screening in Canada: An Overview of Screening Participation for Breast, Cervical and Colorectal Cancer. Toronto (ON): Canadian Partnership Against Cancer; 2015 Jan. 30 p.
