Combining a name algorithm with a capture-recapture method to retrieve cases of Turkish descent from a German population-based cancer registry.

An increasing proportion of the 2 million Turkish residents in Germany is reaching the age in which cancer becomes a common health problem. However, data on cancer incidence and survival among Turkish residents are lacking due to incomplete reporting of nationality in German cancer registries. In the population-based cancer registry of the Saarland, retrieval by reported nationality yielded only 38% (95% confidence interval (CI): 31-45%) of the estimated number of Turkish cases in the registry; furthermore, nationality information was found to be inaccurate, and completeness dependent on the vital status of cases. A newly developed algorithm based on family names retrieved 85% (95% CI: 79-90%) of Turkish cases. Combining the two sources in a capture-recapture approach yielded 91% (95% CI: 86-94%) of the estimated total number of Turkish cases. Hence, the name-based algorithm provides a new and attractive tool for valid registry-based cancer research among Turks in Germany.