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Ontario Cancer Registry

We get our data from the Ontario Cancer Registry, which includes information about all newly-diagnosed cases of invasive neoplasia, except for basal cell and squamous cell skin cancers, in Ontario. The registry collects the data from multiple sources. Electronic records are linked at the person level and then “resolved” into incident cases of cancer using computerized medical logic.

We operate the Ontario Cancer Registry under the authority of the Cancer Act of Ontario and the Personal Health Information Protection Act (PHIPA) of Ontario.

Major data sources

  • Cancer-related hospital discharge and day surgery records from the Canadian Institute for Health Information
  • Cancer-related pathology reports, received mostly electronically from hospital and community laboratories
  • Consultation and treatment records of patients referred to one of 14 Regional Cancer Centres
  • Death certificates with cancer identified as the underlying cause of death, received from the Ontario Registrar General.

Changes to Ontario Cancer Registry

This video provides an overview of the new Ontario Cancer Registry, focusing on its history, data sources, linkage practices and case counting rules in an effort to promote the potential uses of registry data and to inform the analytic methods required for its application.

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Frequently Asked Questions & Answers

Ontario Cancer Registry Information System Decommission & the New Ontario Cancer Registry

The Ontario Cancer Registry (OCR) is the provincial database of information for all Ontario residents who have been diagnosed with cancer (“incidence”) or who have died of cancer (“mortality”). OCR data is collected from hospitals, regional cancer centres, pathology reports and death certificates and covers the entire province of Ontario.

On Oct. 29, 2014, CCO’s Ontario Cancer Registry Information System (OCRIS) was formally decommissioned and replaced with the new Ontario Cancer Registry (OCR).

This is the first and complete revision of Ontario’s cancer registry rules and technology since the early 1980s. As an evidence-based organization, CCO recognizes the importance of adopting new technology and advanced standards to ensure high quality data.

The new OCR better aligns to current medical understanding and more adequately reflects the diagnosis and treatment patterns we see today for Ontario cancer patients regarding the capture of the type and number of cancer cases. The new rules allow a more complete accounting of cancer incidence.

The OCR provides higher quality cancer data in line and consistent with cancer data reporting standards throughout Canada and the U.S. The new OCR also enables integrated reporting of registry and other data (e.g., staging, treatment, etc.).

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.

For international reporting of cancer incidence, the OCR will continue to use reporting standards as set out by the WHO’s International Agency for Research on Cancer (IARC) to align with how countries outside of North America report on cancer.

The new OCR applies specific NCI SEER standards from years 2010 and later. The historic OCRIS cases (1964-2009) have been imported into the OCR to allow for continued use for analytic purposes. If your report spans the cut-over from OCRIS to OCR cases, special care must be taken to reconcile the different data sets. For comparison purposes, data from 2010 and beyond must be converted using IARC rules to ensure equivalent comparison with data from 2009 and before.

OCRIS rules were very conservative compared to the SEER rules used in the new OCR. OCRIS rules did not recognize paired organs (e.g., left or right breast or lung) or colon and skin melanoma subsites. This resulted in only one cancer per person in breast or skin cancer, for example, regardless of how many new cancers developed in those organs.

OCRIS also did not have timing rules to allow new, subsequent primary cancers in the same organ. OCRIS would not recognize different types of cancer in the same organ – it would only count one of them.

By contrast, the new OCR counts left and right breast cancers, and does the same for all paired organs. It will also count: a new primary cancer in the same organ after specified time frames; melanomas of the arm, leg or trunk, for example, as separate primary cancers; and ductal carcinoma and then a sarcoma of the same breast as two primary cancers.

The adoption of specific NCI SEER standards with the new OCR is expected to increase 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.

You will likely start seeing the changes in data reporting immediately for data requested from 2010 onward. All CCO staff who work with the new OCR and access data on the new registry have been trained on the new system and the new guidelines.

One of the mandates of CCO is to provide reliable, high-quality data. It is important for CCO to modernize its systems and processes to ensure the quality and reliability of its data to help increase reporting and business intelligence capabilities.

The new OCR better aligns to current medical understanding and more adequately reflects the diagnosis and treatment patterns we see today for Ontario cancer patients regarding the capture of the type and number of cancer cases. The new rules allow a more complete accounting of cancer incidence.

The new OCR improves the ability for regions and communities to plan for future needs of the cancer system.

For specific information about or requests from the OCR, you can send an email to

Last modified: Tue, May 19, 2015
cancer care ontario | action cancer ontario   620 University Avenue Toronto Ontario, Canada M5G 2L7   Phone: 416.971.9800 Fax: 416.971.6888

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