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about cancer incidence and death data

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Need help understanding the data contained on this site?

  • For each data source, information about data collection and analytical methods, limitations, the citation and additional resources can be found on the Data Sources and Methods page.


Original source: Cancer Care Ontario (CCO)
Distributed by: Cancer Care Ontario (CCO)
Cite as: Ontario Cancer Registry, 1986-2016, Cancer Care Ontario. SEER*Stat Package Release 11 (Dec 2018), released June 2019.


Data collection methods

  • The Ontario Cancer Registry (OCR) contains information on all Ontario residents who have been newly diagnosed with cancer (‘incidence’) or who have died of cancer. The OCR is a passive registry which links data from four major data sources:
    • >Hospital discharge and ambulatory care records with cancer diagnoses,
    • Pathology reports with any mention of cancer from hospitals and private laboratories,
    • Records from Regional Cancer Centres or Princess Margaret Hospital, and
    • Ontario death certificates with cancer as the underlying cause of death.
  • In 2010, the OCR replaced the previous Ontario Cancer Registry Information System (OCRIS).
  • Cancer diagnoses are classified according to the International Classification of Diseases for Oncology, 3rd edition (ICDO-3).
  • Beginning with 2010 diagnoses, the OCR adopted the "SEER Multiple Primary and Histology Coding Rules" for counting additional primary cancers (incidence only). As a result, there is an increase in the number of new cases compared to pre-2010 incidence counts. 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. These new counting rules are not applied to cancer death data.
  • The most recent release of cancer incidence data can now include in situ cases, if desired. The sites with the most in situ cases are cervix, melanoma, bladder, breast and prostate. These data have not been included in the incidence trend analyses, the analyses by age group, or the leading sites analyses.
  • The recommended variable for analysis of cancer incidence sites in this release of data is called “Site Recode ICD-O-3/WHO 2008”. In this version, the site recode for Liver is defined as “Liver, primary”. This is different than previous releases when it was defined as “Liver, primary or secondary”. Thus, the new definition will produce fewer counts of liver cancer than in previous releases of SEER*Stat data.

Data Analysis methods

  • Analyses are conducted using the SEER*Stat Rate Session function.
  • The numerator was all individuals residing in Peel or Ontario who were newly identified in that year (incidence) or died with a specific site of cancer as the cause of death.
  • The denominator was all individuals living in Peel or Ontario (excluding those with unknown place of residence).
  • Rates were presented as age-standardized rates per 100,000 population, standardized using the 2011 Canadian population.
  • Data were suppressed where the number of cases were fewer than six (6), as per CCO's Confidentiality Agreement (denoted with "NR" for "Not releasable due to small numbers"). However, in producing charts depicting the same information, some rates that have been suppressed due to small numbers were not shown as such; instead, they appear as zero. For the correct values, the user can refer to the related table.
  • In order to present incidence trend data that extended over the period ending 2009 and the period starting 2010, a special filter needed to be applied called the “IACR Multiple Primary Flag”. Use of this filter meant that, for cases for the years 2010 and beyond, only those that met the older, more conservative International Association of Cancer Registries (IACR) multiple primary rules were selected.


  • Currently, this data source only provides information at the Census Division (CD) or Public Health Unit (PHU) level of geography.


  • Parts of this material are based on data and information compiled and provided by Cancer Care Ontario. However, the analyses, conclusions, opinions and statements expressed herein are those of the author, and not necessarily those of Cancer Care Ontario.


  1. Cancer Care Ontario.

Last updated: March 27, 2020

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