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Cancer Incidence in First Nations Peoples in Ontario Methodology

Cancer Incidence in First Nations Peoples in Ontario
Short description of Indicator

Age-standardized incidence rate: the number of new cases of cancer that would occur in First Nations peoples if it had the same age-distribution as a given standard population (1960 World Standard), per 100,000 population during a defined time period.

Trend of cancer incidence: the annual number of new cases of cancer diagnosed by year from 1991 to 2010

Rationale for measurement While population measures of cancer incidence is regularly captured among people in Ontario, there is very little information on cancer burden among First Nations in Ontario. Cancer incidence is an important measure for 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 resources and programs in the communities, 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 (by cancer type): (SUM (age-specific incidence rate in a given age group x standard population in that age group) / (total population in the standard population)) x 100,000

Analysis:

  • Breast cancer was only examined among females
  • For all cancers (ICD-O-3 topography code: C00.0-C80.9), cancer of the female breast (C50.0-C50.9), colorectal (C18.0–C20.9, C26.0), lung (C34.0–C34.9), prostate (C61.9), by sex, Ontario, 1991-2010.
    • Rates were standardized using 1960 World Standard population as the standard population. Observed incidence rates 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.
    • Trend in incidence over time was analyzed using Joinpoint regression software. Statistical significance was determined if the trend (slope of the line) was significantly different from zero.
Standardized Rate Calculation Rates were standardized using 1960 World Standard population as the standard population.
Unit ​N/A
Data sources
  • Ontario Cancer Registry, (Cancer Care Ontario)
  • Population data: Registered Persons Database (RPDB) and Indian Registration System (IRS) from Institute for Clinical Evaluative Sciences
  • The IRS was linked to the RPDB to identify First Nations people in Ontario. This linked file was then linked to OCR to identify First Nations in Ontario with a cancer diagnosis between 1991 and 2010.
Time Frame ​1991-2010
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 most cancer types , 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.
  • Because of changes in diagnostic practices or rules of coding and registration, interpretation of temporal trends must be done with caution.
Data availability & limitations
  • IRS only includes Registered First Nations; therefore, this analysis does not include non-Registered First Nations in Ontario.
CSQI Year 2019