Linking claims and cancer registry data: is it worth the effort?

Insurance claims and cancer registries represent different sources of data, each with advantages and limitations insofar as describing severity of illness, cost, utilization, and outcome of care for cancer patients. Although registries typically are able to identify stage of disease and initial course of treatment, claims-based data include more detailed information on the cost and utilization of medical-care services. Moreover, claims data can provide critical information about the use and location of medical services prior to diagnosis of cancer. The purpose of this paper is to argue the advantages of merging claims with registry data by considering evidence and insights from the literature. We discuss the advantages and disadvantages of claims data, describe studies that compare claims and registry data, and highlight the advantages of linking both sources of data. The latter is accomplished by considering a major advantage of each source of data. Registry data contain useful measures of severity of illness (cancer stage, tumor size, and sites of metastasis), whereas claims data include a detailed history of the cost of medical service.