Cancer detection rate (CDR)

Why is it important? The cancer detection rate is indicative of how effective the screening program is at finding cancers over time. The rate of cancer detection during screening is influenced by several factors including age, prevalence, the screening modality used, the screening interval and the diagnostic interval. Cancer detection rates are not to be interpreted in isolation. They provide meaningful insights when considered together with post-screen cancer detection rate, abnormal call rate and the underlying rate of breast cancer in the eligible population.

Breast cancer screening detects both ductal carcinoma in situ (DCIS) and invasive cancers. A DCIS is a non-invasive abnormality in the lining of the breast duct and has a variable probability of becoming invasive.¹

Indicator definition: The number of breast cancers detected per 1,000 screens.

Target:

• Invasive cancer detection rate:
  • Initial screen: >5 per 1,000 screens
  • Subsequent screen: >3 per 1,000 screens
• In-situ cancer detection rate:
  • No target.

Measurement timeframe:

• January 1, 2019 to December 31, 2019
• January 1, 2020 to December 31, 2020

Indicator calculation:

• Numerator: The number of screens found to have breast cancers (DCIS or invasive) within 6 months of screening.
• Denominator: The total number of screening mammograms performed in the measurement timeframe.
  • Exclusions: Breast cancer screens of individuals that were lost to follow-up within 6 months of screening.

Cancer detection rate (per 1,000 screens) of breast cancers among individuals aged 50-74, who were screened within a screening mammography program, by jurisdiction — 2019 and 2020

_{Data table and footnotes}

The cancer detection rate (combined for both DCIS and invasive cancers) across most jurisdictions remained relatively consistent, ranging from 3.6 per 1,000 screens to 6.5 per 1,000 screens in 2019 and 5.3 per 1,000 screens to 6.6 per 1,000 screens in 2020.

Cancer detection rate (per 1,000 screens) of breast cancers among individuals aged 50-74, who were screened within a screening mammography program, by jurisdiction and age group — 2019 and 2020

_{Data table and footnotes}

The cancer detection rate (combined for both DCIS and invasive cancers) was relatively consistent across jurisdictions. It increased with age in both 2019 and 2020 across most jurisdictions. The  cancer detection rate for the different age groups in 2020 ranged from:

• 50-59 years: 3.8 per 1,000 screens to 4.8 per 1,000 screens
• 60-69 years: 5.4 per 1,000 screens to 7.2 per 1,000 screens
• 70-74 years: 6.9 per 1,000 screens to 9.3 per 1,000 screens

Cancer detection rate (per 1,000 screens) of breast cancers among individuals aged 50-74, who were screened within a screening mammography program, by jurisdiction and screening sequence — 2019 and 2020

_{Data table and footnotes}

The cancer detection rate (combined for both DCIS and invasive cancers) was higher in initial screens compared to subsequent screens in both 2019 and 2020. While there was some variability in cancer detection rate across jurisdictions for initial screens, the rate for subsequent screens across most jurisdictions was relatively consistent. In 2020, the cancer detection rate for initial screens ranged from 5.7 per 1,000 to 10.8 per 1,000 and from 4.9 per 1,000 to 6.3 per 1,000 for subsequent screens. The performance of this indicator in all jurisdictions exceeded the national target of >5 per 1,000 for initial screens and >3 per 1,000 for subsequent screens.