Health Research Working Paper Series

    The feasibility of adding treatment data to the Canadian Cancer Registry using record linkage

    The feasibility of adding treatment data to the Canadian Cancer Registry using record linkage

    by Carrière GM,Note 1 Sanmartin C,Note 1 Trudeau R,Note 2 Murison P,Note 2 MacIntyre M,Note 3 Turner D,Note 4 King MJ.Note 5 Vriends K,Note 6 Woods R,Note 7 Louchini R,Note 8 Wagar B,Note 9 Lockwood GNote 10


    Our gratitude and thanks are extended to the following people: Carol Russell, former Director of the Alberta Cancer Registry, Alberta Health Services, and Kim Boyuk, former Chief, Cancer Statistics, Health Statistics Division, Statistics Canada, for their earlier regular involvement in this study; Dr. Geoff Porter, for sharing his expertise and experience regarding clinical aspects of dual diagnoses in patients with colorectal cancer; Mary Sue Devereaux, Senior English Editor, Health Analysis Division, for her assistance in editing this manuscript; Dianne Zakaria, Health Statistics Division, for her development of methods to directly link the CCR to the DAD and for her earlier assistance in reviewing coding and preliminary results.

    Executive Summary

    The Canadian Cancer Registry (CCR) represents a collaborative effort between Statistics Canada and the thirteen provincial and territorial cancer registries to create a single database to report annually on cancer incidence and survival at the national and jurisdictional level. While gains have been made to ensure high quality, standardized, and comparable data, the CCR currently lacks information on cancer treatment. The Canadian Council of Cancer Registries (CCCR) identified the need to capture treatment data at the national level as a key strategic priority for 2013/2014. Record linkage was identified as one possible approach to fill this information gap.

    The purpose of this study is to examine the feasibility of using record linkage to add cancer treatment information for selected cancers―breast, colorectal and prostate. The objectives are twofold: to assess the quality of the linkage processes and the validity of using linked data to estimate cancer treatment rates at the provincial level. The study is based on the Canadian Cancer Registry (2005 to 2008) linked to the Discharge Abstract Database (DAD) and the National Ambulatory Care Reporting System (NACRS) for four provinces (Ontario, Manitoba, Nova Scotia and Prince Edward Island). The linkage was proposed by Statistics Canada, the CCCR and the Canadian Institute for Health Information (CIHI). The linkage was approved and conducted at Statistics Canada.

    Key findings:

    • High level of eligibility for linkage among CCR tumours: Overall, 97% to 100% of breast, colorectal and prostate tumours identified from 2005 to 2008 in the four provinces were eligible for linkage;
    • Linkage rate varied by tumour type and availability of data across provinces: Approximately 95% of eligible tumours were linked to the DAD/NACRS. Linkage rates for prostate tumours varied across provinces from 75% in Manitoba to over 90% in Ontario, for which NACRS data were available.
    • Overall treatment rates varied by tumour type and availability of data across provinces: About 90% of breast and colorectal tumours were linked to at least one type of treatment. Overall treatment rates varied for prostate cancer from 75% in Ontario (DAD and NACRS) to 42% in Manitoba.
    • Feasibility of using CCR linked to hospital data to report on cancer treatment varied across treatment types: The CCR linked data produced expected surgical treatment rates, as surgery is commonly reported as either an inpatient or outpatient service in the DAD. Rates for treatments occurring in other healthcare settings, such as radiation and pharmacotherapy, were consistently low in all provinces except Ontario where the NACRS data were available and which captures treatments performed in oncology centres and clinics.
    • Limitations of using linked data to report treatment rates are largely determined by the availability of high quality, comprehensive and standardized treatment information: The CCR linked to DAD and NACRS (Ontario only) could feasibly be used to report on treatments such as surgery performed as either day or acute care hospital procedures; more comprehensive data are required to feasibly report on treatments conducted outside of acute care and day surgery settings such as radiation and pharmacotherapy.


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