Emigration patterns of cancer cases in Alberta, Canada

Cancer registries are a unique source of data for population-based analysis of survival of cancer cases, but information on current vital status is essential. This paper describes a method to determine the last known vital status of cases and the emigration pattern of cancer cases diagnosed in Alberta. Data from the Alberta Cancer Registry (ACR) for the years 1985 1993 (83,446 cases), were linked to the Alberta Health Care Insurance Plan (AHCIP) registration file to identify cases that had left the province, and the date they emigrated. Ninety-nine percent of the ACR cases linked correctly to the AHCIP registration file. Three percent of cases had left Alberta by March 1998; For the first five years of follow-up between 0.6% and 0.8% of cases alive at the beginning of each year of follow-up left the province in the succeeding year. Seven percent of those diagnosed under 45 years of age left the province compared to less than 2% of those aged 65 and over. There was no difference in emigration patterns between the sexes. The cancer sites with good prognosis tended to have the highest proportion of emigrants.