Use of administrative hospital registry data and a civil registry to measure survival and other outcomes after cancer

For many decades, cancer registries have been a cornerstone in monitoring cancer occurrence in different populations. Cancer registries in the Nordic countries are characterized by a high level of completeness and excellent data quality. 1 Cancer diagnoses are often validated through several procedures, with documentation of clinical evidence for the diagnosis. Cancer registries have proven very useful in monitoring cancer incidence, contributing significantly to our understanding of its origin and development. Some registries also have been used to monitor cancer survival at the population level. 1 Since the early 1990s there has been an increasing demand to measure the performance of health care systems in treating a number of diseases, including cancer. 2 " Outcomes " refers to the results of the health care delivery process. 3 For cancer treatments, the main outcomes are: 1) clinical status, including survival; 2) functional status; and 3) consumer satisfaction. Five-year overall survival has long constituted the main clinical outcome in cancer research. 2 The aim of any system designed to monitor the performance of a health care system is to help clinicians and health care administrators detect suboptimal clinical practices and to guide clinical decisions and policy, with the overall goal of achieving measurable improvements in health care. 3 An effective monitoring system must fulfill the following requirements: 4 1. Data must be continuously updated. 2. Data must be complete and of adequate quality. 3. Data must be accessible on a regional level, and preferably also on a hospital level. 4. Data must contain relevant clinical endpoints. 5. Data must be collected continuously in clinical practice. Cancer registries often are limited in these respects. One problem is lag time in data delivery (in some cases several years). Another is that information on treatment is restricted to that available at the time of diagnosis. As well, some registries do not provide linkage to mortality data. Finally, data collected by cancer registries are not routinely returned to clinical departments, limiting the feedback received by the specific health care delivery points. Many cancer registries thus provide only an incomplete view of the clinical course of cancers. In this Supplement to Clinical Epidemiology, current survival data after cancer treatment in Denmark are reported on a regional level. The analyses were based on administrative hospital registry data linked to a civil registry, both of which are available