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Cancer Incidence Methodology

Cancer Incidence
Short description of Indicator Age-standardized incidence rate: the number of new cases of cancer that would occur in a specified population if it had the same age-distribution as a given standard population, per 100,000 population during a defined time period.
Rationale for measurement Cancer incidence is an important measure of cancer burden on the population and on the healthcare system. Monitoring trends in cancer incidence and the distribution of new cases of cancer by cancer type and demographic factors, such as age and sex, assists in informing and evaluating cancer control efforts along several parts of the cancer journey, from prevention (e.g., risk factor reduction) to early detection (i.e., screening) and treatment. Monitoring incidence trends also assists in predicting future cancer burden to help plan for upcoming resource, policy and research needs.
Evidence/references for rationale This is a well-established cancer burden indicator, described and reported on by numerous provincial, national and international organizations, including:
Calculations for the indicator

Age-standardized incidence rate: [∑(age-specific incidence rate in a given age group x standard pop in that age group) ÷ total population in standard population] x 100,000

Analysis:

  • For female breast (C50.0-C50.9), colorectal (C18.0–C20.9, C26.0), lung (C34.0–C34.9), and prostate (C61.9) cancers, by sex, Ontario, 2012–2016.
    • Rates were standardized using 5-year age groups with the 2011 Canadian population as the standard population.

Observed incidence rates and trends were based on the National Cancer Institute's Surveillance, Epidemiology and End Results (NCI SEER) program standards for counting multiple primary cancers, which were adopted by the Ontario Cancer Registry for cases diagnosed in 2010 and beyond.

Standardized Rate Calculation Rates were standardized using 5-year age groups with the 2011 Canadian population as the standard population.
Unit N/A
Data sources
  • Ontario Cancer Registry, 2018 (Cancer Care Ontario)
  • Population data: Ontario Ministry of Finance. Ontario Population Projections (based on the 2011 Census released by Statistics Canada February 2015). Spring 2018 release.
Time Frame 2012-2016
Geographic Scale Provincial
Denominator description N/A
Numerator description N/A
Considerations 
  • On Oct. 29, 2014, CCO's Ontario Cancer Registry Information System (OCRIS) was formally decommissioned and replaced with the new Ontario Cancer Registry (OCR). The new registry brings the OCR in line with current Canadian and U.S. standards for tracking cancer incidence. The OCR now conforms to specific standards as set out by the National Cancer Institute's Surveillance, Epidemiology and End Results (NCI SEER) program for counting multiple primary cancer sites, which most Canadian provinces and U.S. states now use. The adoption of specific NCI SEER standards with the new OCR has resulted in an increase in the incidence number of certain types of cancer reported in Ontario. However, this change in number is due to how cancers are being counted; it does not mean that more people in Ontario are being diagnosed with cancer or dying of cancer. This change impacts cancer incidence for 2010 and beyond, as such direct comparisons with incidence for 2009 and years prior should not be made.
  • Cancers were defined using U.S. Surveillance, Epidemiology and End Results (SEER) Site Recode definitions: http://seer.cancer.gov/siterecode/icdo3_dwhoheme/index.html. Cancer definitions using SEER Site Recode may differ, especially for cancers of the colon and rectum and lung cancer, from definitions in other published analyses.
  • For breast and prostate, the full site grouping name outlined by the SEER site recode variable definitions was used. Short titles for certain cancers, however, were, used for graphing purposes. Cancer types for which short titles were displayed are as follows:
    • Lung and bronchus (ICD-O-3 code C34.0–C34.9): short title “Lung"
    • Colon and rectum (ICD-O-3 code C18.0–C18.9, C19.9, C20.9, C26.0): short title “Colorectal" 
  • The use of a standard population allows incidence rates to be compared across time periods and jurisdictions by adjusting for differences in the population age distribution over time and across geographic areas. The 2011 Canadian population standard is specified by Statistics Canada.
  • Because of changes in diagnostic practices or rules of coding and registration, interpretation of temporal trends must be done with caution.
Data availability & limitations Incidence was calculated for cancers diagnosed through 2016, the most recent year for which the Ontario Cancer Registry had received complete data at the time of analysis. ​
CSQI Year 2019