The Alberta Cancer Registry, in common with other provincial and territorial registries does not actively follow up cancer cases. Thus the vital status of the cancer cases is only known for those cases who are deceased. Statistical Factors One possible function of a cancer registry is the analysis of the survival statistics of the population of cancer cases. The proportion of cancer cases surviving at given time depends on many factors, including the age distribution of the population, certain pathological features of the tumour, the stage at which the tumour is diagnosed, the type of treatment given, access to medical services and other demographic measures. Analysis of the relationship of survival to these factors could inform health policy in regard to the availability of screening services and access to diagnostic and therapeutic services, particularly for high-risk groups.
Information regarding certain key variables is required to undertake survival analyses.
These are an accurate diagnosis, the date of diagnosis, and the date of death if the case has died, or the last known date to be alive if the case is not known to be dead. Other demographic, pathological and stage data are necessary for a full interpretation of survival data. Because of a lack of good follow-up data on those cases not known to be dead, cancer registries in Canada do not routinely publish survival statistics for cancer cases. The survival analysis included cancer cases diagnosed between 1985 and 1993, it excluded those cases with a diagnosis of non-melanoma skin cancer, cases who had more than one primary cancer, and cases who were registered only from death information. For the major cancer sites, cause specific survival curves, which reflect mortality attributable to the specific cancer, were calculated using Kaplan Meier techniques.