LAUSR

Cancer screening and care quality registries provide essential data for descriptive cancer statistics, not least in the Scandinavian countries. In Norway, Denmark and Sweden, respectively, there are between 10 to just over 30 such registries for various cancer types [1]. Advances in descriptive cancer epidemiology are dependent on further, easily accessible data from those registries. I have argued that data at the small-residential-area level should be prioritised for descriptive cancer epidemiology [2,3]. As compared with using data at a larger geographical scale, such as commonly available data at the regional level, the small-area representation provides more informative estimates on sociodemographic and spatial variations in cancerrelated outcomes [4,5]. Linkage of an identifier variable for small areas to individual-level data in cancer screening and care quality registries is feasible [2]. I am not aware of any quality registry that provides open-access data at the smallarea level. I believe that there are two main reasons for this lack of open-access data. First, registries have focussed on gathering clinical data on patients (or screened persons), generally leaving out the population perspective. Specifically, registries have not prioritised variables that provide a link to underlying population groups and therefore they miss the opportunity to consider population-wide data on sociodemographic and geographical characteristics [2]. Second, it is unrecognised that data at the small-area level can be kept anonymous. In this Letter, I make the case that anonymous data at the small-area level could be made available from registries with data on: