Arctic Medical Research, Vol. 47: Suppl. 1, pp. 624-627, 1988 DEVELOPMENT OF A CANCER REGISTRATION SYSTEM FOR THE INUIT OF CANADA L. A. Gaudette (1) and L. A. V. Barreto (2) Health Division, Statistics Canada, Ottawa, Ontario (1) and Department of Health, Government of the N.W.T., Yellowknife· (2), Canada Abstract. A cancer registry, now under development for the Inuit in Canada, will be used to monitor national and international trends, to conduct analytic epidemiologic studies, and (potentially) to evaluate intervention studies designed to reduce public health problems associated with cancer in the Inuit. It is expected that several hundred Inuit with cancer will be identified from the one million cancers which have been reported by the provincial and territorial registries since 1969. To overcome the formidable logistical problems posed by geographic dispersion of the population, multiple sources of information, and legal requirements for data transfer, the following strategy has been devised for inclusion of cases on the registry. First, information will be restricted primarily to Inuit residing in Arctic regions (since of the 25,390 Inuit residing in Canada in 1981, just 13% lived in southern Canada, whereas 63% were in the Northwest Territories, 18% in northern Quebec and 6% in Labrador). Second, because Inuit with cancer are often treated in provinces other than the province or territory of residence, all provincial cancer registries involved have agreed to identify and report potential cases. Where necessary, legal agreements are being drawn up to permit exchange of records. Third, the data will be consolidated at Statistics Canada, using case definitions of the National Cancer Incidence Reporting System (NCIRS); duplicates will be eliminated and discrepancies will be resolved in diagnostic information obtained from several sources. Fourth, the time period will be from 1969 onwards (to conform to the years covered by the NCIRS). Finally, Inuit status will be determined by reference to the previous series of Inuit with cancer identified by Drs. Schaefer and Hildes, supplemented by various sources of information available at the provincial and territorial levels. Results of preliminary work at the provincial, territorial and national levels indicate that the proposed approach is feasible. Successful completion of this project is expected to lead to a fully consolidated registry for the Northwest Territories from 1969 onwards, as well as to improved operational procedures (particularly with regard to exchange of information) for the NCIRS in Canada. Arctic Medical Research, vol. 47: suppl. 1, pp. 624-627, 1988. Documentation of cancer in the Inuit population of participate. However, because of difficulties in deter­ Canada was first begun by Dr. Otto Schaefer and Dr. mining ethnic status for the several hundred Inuit pre­ J. A. Hildes, who identified a series of cases in the sent among the over one million records on the Na­ western and central Arctic for the years 1950-1980 tional Cancer Incidence Reporting System (NCIRS), (1,2). Statistics Canada's involvement in the study of progress in Canada was limited. Finally, a meeting, cancer in the Inuit population began after the 13th In­ convened in May 1986 in Montreal, was attended by ternational Cancer Congress held in Seattle in 1982, representatives from Denmark and Alaska, several when Dr. Calum Muir of the International Agency for Canadian researchers (including Dr. Otto Schaefer), Research on Cancer wrote to Statistics Canada. In and persons involved in collection and processing of subsequent working group meetings, at the interna­ cancer registrations at both the national and provincial tional level, a plan was developed to produce an inter­ level, to discuss means whereby a cancer registration national monograph with Denmark taking the lead system could be developed for the Inuit. role, and Alaska and hopefully Canada being able to During this meeting, a plan was developed to Circumpolar Health 87 Gaudette & Barreto: A cancer registration s_vstem 625 establish a national registry retroactively to 1969 (if vincial registries involved in the Inuit study have all agreed in possible) as well as to prospectively identify Inuit with principle to report non-resident cases they have treated, back to the province or territory of residence. cancer in Canada. Identification of Inuit Status History of Cancer Registration in Canada Cancer registries in the provmce of residence have undertaken Canada is in the fortunate position of being one of the primary responsibility for this step, in line with the following few countries, and certainly one of the largest, in strategies which emerged from the May 1986 meeting in Montreal. Quebec will use the geographic location and then which the entire population is covered by cancer cross-check names with the Inuit population register main­ registration. This is achieved through an interlocking tained in that province. In Newfoundland, geographic loca­ system of 12 provincial/territorial cancer registries tion will also be used as an initial screen, as most Inuit are which contribute information to the National Cancer located in Labrador; Inuit status will be verified_ by contacting local nurses who are very knowledgeable ef the population Incidence Reporting System (NCIRS), a centralized they serve in the small isolated communities. Finally, for the data system maintained at Statistics Canada since Northwest Territories a variety of methods is available in­ 1969 (3). cluding: lists provided by Dr. Schaefer for the period 1950- Because delivery of health care services is primarily 1980; the health care number fr0m 1970 onwards; vital a provincial responsibility in Canada, initial cancer statistics registrations; and the Inuit (Eskimo disc) number prior to 1970. registration is carried out at the provincial level. Each registry attempts to record all new cases of cancer in its Data Consolidation population using a variety of data sources, which may Statistics Canada has undertaken the responsibility for include some or all of the following: cancer clinic and establishing a cancer registry for Inuit at the national level, and consolidating the records for reporting to the interna­ general hospital records, pathology and other tional level. Case definitions established by the NCI RS will be laboratory reports, radiology reports, reports from used, including coding of disease to ICD-9 (from either physicians in private practice, and reports on cancer ICDA-8 or ICD-0 depending on the time period). While cases deaths from Vital Statistics Registrars (4). Core patient will be histologically verified where possible, other methods and diagnostic information for each new primary of diagnosis will also be accepted according to procedures used for the NCIRS. Morphology will also be included for neoplasm is then reported to NCIRS. more recent years. The success of this project hinges on developing a good METHODS: SCOPE AND STRATEGIES historical cancer registry for the Northwest Territories, which involves resolving information from a wide variety of sources. Time Frame Statistics Canada is working closely with the Northwest Ter­ Based on Dr. Schaefer's work, information is available on ritories, as well as the other provincial cancer registries, to use many Inuit with cancer back to the early 1950's (l, 2). Howev­ data already on the NCI RS and to provide technical and other er, because the NCIRS did not begin until 1969, this date has assistance where required. been chosen as the earliest feasible date from which to collect information. RESULTS TO DATE Geographic Area Northwest Territories (NWT) A major simplifying assumption has been to limit the study to Inuit residing in the northern regions, since of the 25,390 Records have been obtained from a variety of sources Inuit enumerated in Canada during the 1981 censu'.; (5), just including: residents treated for cancer from the four 13% lived in southern Canada, whereas 63% were in the western provinces, records previously reported to Northwest Territories, 18"70 in northern Quebec and 60/o in Labrador. NCIRS by Medical Services Branch, Health and Welfare Canada, morbidity records from the health Registration of Cancer Cases care plan, lists provided by Drs. Schaefer and Hildes This responsibility is generally that of the province of and vital statistics records of deaths. Data on NWT residence. However, because most residents of northern regions receive medical treatment for cancer in the southern residents treated in Quebec and Ontario will be provinces, most of their cancers are first registered in the pro­ reported once legal authorizations have been ob­ vince of treatment. In the past, not all of these cases were tained. reported back to the province or territory of residence. The situation is further complicated because responsibilities for Quebec northern health care, including cancer registration, have recently been transferred from the Medical Services Branch Inuit records from 1972 to 1982 have been forwarded to of Health and Welfare Canada to the Governments of the Statistics Canada, and work is ongoing to identify Northwest and Yukon Territories. Nevertheless, the seven pro- these for 1983 and 1984, as well as for the years 1969- Circumpolar Health 87 626 Cancer 71. Agreements to exchange cancer records with the Hildes but not found by STC or NWT. This will involve NWT anJ Ontario have been prepared and are current­ returning records to the province of treatment to check ly undergoing review prior to approval. their records. If no registration can be found, then the provincial registry would have the option of contacting Newfoundland the hospital to obtain pathology reports and initiate a Cases identified from both the Newfoundland cancer registration. registry and the NCIRS are being evaluated to deter­ Second, further passive follow-ups of cancer cases mine Inuit status, as well as completeness of registra­ with "possible" Inuit status, as well as of pathology tions in the affected areas, particularly for the earlier reports for which no registrations have been received, years. can be attempted by searching the Mortality Data Base maintained at Statistics Canada (6).