Canadian Cancer Registry (CCR)

Detailed information for 2007

This is an administrative database that collects information on cancer incidence from all provincial and territorial cancer registries in Canada.

Data release - October 27, 2009

• Description
• Data sources and methodology
• Data accuracy

Description

In 1992, the person-oriented Canadian Cancer Registry (CCR) evolved from the event-oriented National Cancer Incidence Reporting System established in 1969. The CCR is an administrative database. Beginning with cases diagnosed in 1992, cancer incidence data collected by provincial and territorial cancer registries (PTCRs) have been reported to the CCR, which is maintained by Statistics Canada.

The CCR is a collaboration between the 13 Canadian PTCRs and the Health Statistics Division of Statistics Canada, where the data are maintained. Ultimate authority and responsibility for the completeness and the quality of the data reside with the provinces and territories. The data that comes into the CCR describes both the individual with the cancer, and the characteristics of the cancer.

The primary objective of the CCR is to provide a national database of information that can be used to produce standardized and comparable statistics for cancer incidence and survival data for each primary type of cancer. This information is used to assist and support health planners and decision-makers at all levels of government to: identify risk factors for cancer; plan, monitor and evaluate a broad range of cancer control programs (e.g., screening); and, conduct research in health services and economics.

The CCR is a dynamic database of all Canadian residents, alive or dead, who have been diagnosed with cancer since 1992. The CCR is a patient-based system that records the type and number (incidence) of primary cancers diagnosed for each person until death. Subsequent primary cancers occurring for patients who are already in the database are linked to their existing patient information. The advantage of this system is that longitudinal data is available for each cancer patient. The patient data is regularly linked to mortality data (death clearance) to optimize the accuracy of date, cause, and place of death fields in the CCR and to identify potential primary cancers not currently registered in the CCR. Since patients' records remain active on the CCR until confirmation of their death, survival rates for the various forms of cancer can be calculated.

In addition, the CCR regularly employs internal record linkage to identify and eliminate duplicate patient and tumour records. Conflicting information and other problems with the data uncovered by CCR processes are resolved through consultation with the reporting provinces and territories.

For more details, see "History of the Canadian Cancer Registry" in the Documentation section.

Reference period: Calendar year

Collection period: Fifteen months after the end of the reference period.

Subjects

• Diseases and health conditions
• Health
• Health care services
• Life expectancy and deaths

Data sources and methodology

Target population

The conceptual universe of the Canadian Cancer Registry database is persons whose usual place of residence is Canada or who are non-permanent residents. The residence at diagnosis is generally the place of usual residence, as stated by the patient or, as defined by the Census, "the dwelling in Canada where a person lives most of the time", regardless of where they are when diagnosed. For patients diagnosed with multiple primary tumours over time, the address may be different for each primary tumour.

The conceptual universe of the CCR is persons whose usual place of residence is Canada (residents) or foreign citizens (non-residents) who are in Canada for a continuous period of six months or more at the time of diagnosis. The residence at the time of diagnosis is generally the place of usual residence, as stated by the diagnosed person or, as defined by the Census, "the dwelling in Canada where a person lives most of the time", regardless of where they are when diagnosed. For patients diagnosed with multiple primary tumours over time, place of residence may be different for each primary tumour.

For detailed information on CCR universe or residency guidelines, please contact Health Statistics Branch Client Services (613-951-1746 or hd-ds@statcan.gc.ca).

Instrument design

This methodology does not apply.

Sampling

This survey is a census.

Data are collected for all units of the target population, therefore, no sampling is done.

Data sources

Data are extracted from administrative files.

The Canadian Cancer Registry (CCR) is comprised of administrative data. Each provincial and territorial cancer registry supplies data on cancer patients and tumours in a standard, pre-edited format, on diskette or CD-ROM. Each year, approximately 145,000 new cancer tumour records are loaded on the Canadian Cancer Registry (CCR) patient-oriented database which is housed and maintained at Statistics Canada. Subsequent changes to registrations due to errors or omissions are also transmitted to Statistics Canada, as the information becomes available. Cancer records are loaded on the CCR database and those failing edits that ensure the validity of each data field and check the compatibility of different data elements within a record, are rejected and returned to the province or territory for verification or correction. Each provincial and territorial cancer registry has the ability to add, update, and delete records. The CCR can be updated with new records or changes to previous records, as part of regular submissions from the registries to Statistics Canada. The following three software modules perform the tasks of building and maintaining the data in the CCR database: Core Edit, Internal Record Linkage, and Death Clearance. An internal record linkage and a national death clearance of cancer tumours diagnosed since 1992 are done annually.

The Canadian Council of Cancer Registries recommends that the following tumours should be reported to the CCR;

- All primary, malignant tumours (C00.0-C80.9) with behaviour codes of 3; except squamous cell skin cancer (805_-808_) and basal cell skin cancer (809_-811_) with topographies C44._;

- All in situ/intraepithelial/non-infiltrating/non-invasive carcinomas with behaviour codes of 2; except cervix in situ or cervical intraepithelial neoplasia (CIN III) with topographies C53._; except high grade dysplasia, severe dysplasia and prostatic intraepithelial neoplasia (PIN III) for prostate (C61.9);

- All borderline malignancies with behaviour codes of 1; and,

- Primary, benign tumours of the brain and central nervous system (topographies C70.0-C72.9 with behaviour codes of 0).


The list of the Canadian Cancer Registry data elements on the Patient record and the Tumour record is provided in the Canadian Cancer Registry System Guide (see the chronological index of Canadian Cancer Registry Manuals, Catalogue no.: 82-225-XIE).

Error detection

Each cancer registry supplies information to the Canadian Cancer Registry (CCR) for each new patient and each new tumour in a standard, pre-edited format, on magnetic tape or diskette. Validity edits verify that fields contain valid entries and correlation edits verify that relationships between patient and tumour records make sense. Those failing edits are rejected and returned to the provincial and territorial cancer registries for verification or correction. The CCR can be updated with new records or changes to previous records, as part of regular submissions from registries to Statistics Canada. Data are edited by computer to ensure validity of each field and to check on the compatibility of different data elements within a record. An internal record linkage and a national death clearance of cancer tumours diagnosed since 1992 are done annually by Statistics Canada. Although the CCR is an administrative data application, the CCR edits ensure a consistency of editing across all provincial and territorial cancer registries.

Imputation

Statistics Canada does not impute missing data on The Canadian Cancer Registry.

Estimation

This methodology type does not apply to this statistical program.

Quality evaluation

Statistics Canada produces Data Quality Reports that provide detailed feedback to the provincial and territorial cancer registries (PTCRs) on the quality of data submitted each year. These reports provide data quality indicators for all patient and tumour records reported in a given data year.

CCR Data Quality Reports are used by PTCRs to monitor the quality of their information in the CCR and meet standards for acceptance in international publications such as Cancer Incidence in Five Continents and Cancer Incidence in North America.

Before the availability of cancer statistics is announced in The Daily, the publication data files are reviewed and approved for official release by each PTCR.

Disclosure control

Statistics Canada is prohibited by law from releasing any data which would divulge information obtained under the Statistics Act that relates to any identifiable person, business or organization without the prior knowledge or the consent in writing of that person, business or organization. Various confidentiality rules are applied to all data that are released or published to prevent the publication or disclosure of any information deemed confidential. If necessary, data are suppressed to prevent direct or residual disclosure of identifiable data.

The Merrigan-Hortop suppression program is used to suppress low cell counts in cancer data. It suppresses table cells with a small count (from 1 to 5) and then iteratively suppresses additional cells to prevent calculation of the counts in suppressed cells from the released table data. The program suppresses a cell having the minimum value within the most promising class of equivalently-positioned cells at each iteration, but may suppress cells containing any count, including cells with a count of zero but excluding cells which are not applicable or not available. When a cell is suppressed, all measures of incidence (the number, the rate, and the confidence interval for the rate) are suppressed together.

Revisions and seasonal adjustment

This methodology does not apply to this survey.

Data accuracy

Completeness

Since each Canadian province and territory has a legislated responsibility for cancer collection and control, case ascertainment of malignant tumours is considered relatively good. Each provincial and territorial cancer registry (PTCR) identifies tumours in its population by combining information from sources such as: cancer clinic files, radiotherapy and haematology reports; records from in-patient hospital stays, out-patient clinics, and private hospitals; pathology and other laboratory/autopsy reports; radiology and screening program reports; reports from physicians in private practice; medical billing and hospital discharge administrative databases; and, reports on cancer deaths from Vital Statistics registrars. Some PTCRs experience problems in submitting data to Statistics Canada on a timely basis or updating the CCR to reflect the current content of their PTCR.

Designed studies are used by the PTCRs to assess the completeness of case ascertainment (check for under and over-registration of cases). Re-abstraction is used to evaluate accuracy and completeness of reported items.

Duplicates

To avoid duplication, the CCR accepts tumour records only when the reporting PTCR is the same as the province or territory of residence at the time of tumour diagnosis. Each PTCR is required to return records for residents of other jurisdictions to the appropriate PTCR.

Under-reporting

Under-coverage remains a stronger concern than over-coverage because of the following reasons: some PTCRs do not use, or have had periods in the past where they have not used, death certificates as a source of tumour incidence; differing definitions among the PTCRs of what constitutes a reportable or malignant tumour; difficulty in diagnosing certain tumours because of their location (or site) in the body; differences among the PTCRs in coding practices, data entry or processing procedures; and, failure to report tumours diagnosed and treated in a province, territory or country outside of the province or territory of residence.

The CCR has been updated with new records or changes to previous records. Therefore, the incidence for any given diagnosis year may change from one release to the next. In particular, data for the most recent years often represent an undercount of total cases which is due to a delay in the reporting of new cancer cases to the CCR. These cases are generally added with the reporting of the next reference year.

For the years 1992-2012 Ontario did not report in situ bladder cancers to the CCR; did not register non-melanoma skin cancers; and, had underestimated cases of Kaposi's sarcoma.

Because Quebec relies primarily on hospital data (i.e., hospitalizations or day surgeries) for cancers diagnosed until the end of 2010, the number of cases of some cancers are underestimated (source: Brisson J, Major D, Pelletier E. Evaluation of the completeness of the Fichier des tumeurs du Québec. Institut national de la santé publique du Québec; 2003).

Death Certificate Only cases

Cancer incidence may be under-reported for a few Canadian provinces due to missing information on Death Certificate Only (DCO) cases. A DCO case occurs when cancer is discovered through the cause of death information on a death certificate, as opposed to through a cancer report from the medical system. Ontario cancer incidence data have not included DCO cases since 2007. Ontario reported just over 1,000 DCO cases in 2007 (the most recent year that Ontario DCO cases are available). The last time Quebec reported DCO cases was in 2009 (just under 1,400).

Record Linkage

National internal record linkage and national linkage processes between the CCR and the Canadian Vital Statistics Death Database reduce duplicate person and tumour records, identify cases missed by provincial/territorial registries, and enhance the accuracy of vital status information.

There may be under-reporting of cancer cases in Newfoundland and Labrador due to incomplete linkage of cancer data with death data.

Quebec does not participate in national internal record linkage and national linkage between the CCR and the Canadian Vital Statistics Death Database.

Rules for reporting multiple primary cancers

For determining multiple primaries with tumours diagnosed as of January 1, 2007 onward, the CCR adopted the Multiple Primary and Histology Coding Rules from the Surveillance Epidemiology and End Results (SEER) program of the National Cancer Institute (NCI) in the United States. Not all registries were able to report according to the new requirements beginning in 2007. For the purpose of comparability between provinces and territories, the annual release of cancer incidence and survival statistics are disseminated from Statistics Canada using the IARC rules* for determining multiple primary tumours.

*World Health Organization, International Classification of Diseases for Oncology, Third Edition (ICD-O-3) and the International Agency for Research on Cancer (IARC) rules for determining multiple primary types (source: International Agency for Research on Cancer, World Health Organization, International Association of Cancer Registries, and European Network of Cancer Registries. International Rules for Multiple Primary Cancers, ICD-O Third Edition, Internal Report No.2004/02. Lyon: International Agency for Research on Cancer, 2004).

For data reported in 2010 and onwards, 32 new ICD-O-3 histology codes have been added to the CCR for reporting lymphomas and leukemias. These new codes have not been added officially to the IARC rules for multiple primary cancers, but they have been placed into the IARC histology groupings on an interim basis after consulting with IARC and committees associated with the Canadian Council of Cancer Registries.