Ensuring quality in studies linking cancer registries and biobanks.

The Nordic countries have a long tradition of providing comparable and high quality cancer data through the national population-based cancer registries and the capability to link the diverse large-scale biobanks currently in operation. The joining of these two infrastructural resources can provide a study base for large-scale studies of etiology, treatment and early detection of cancer. Research projects based on combined data from cancer registries and biobanks provides great opportunities, but also presents major challenges. Biorepositories have become an important resource in molecular epidemiology, and the increased interest in performing etiological, clinical and gene-environment-interaction studies, involving information from biological samples linked to population-based cancer registries, warrants a joint evaluation of the quality aspects of the two resources, as well as an assessment of whether the resources can be successfully combined into a high quality study. While the quality of biospecimen handling and analysis is commonly considered in different studies, the logistics of data handling including the linkage of the biobank with the cancer registry is an overlooked aspect of a biobank-based study. It is thus the aim of this paper to describe recommendations on data handling, in particular the linkage of biobank material to cancer registry data and the quality aspects thereof, based on the experience of Nordic collaborative projects combining data from cancer registries and biobanks. We propose a standard documentation with respect to the following topics: the quality control aspects of cancer registration, the identification of cases and controls, the identification and use of data confounders, the stability of serum components, historical storage conditions, aliquoting history, the number of freeze/thaw cycles and available volumes.