Six Degrees of Separation No More: Using Data Linkages to Improve the Quality of Cancer Registry and Study Data

A data linkage is a process commonly used to determine if persons in one database also reside in a second database. There are two general types of linkages; deterministic (rules-based) and probabilistic (statistical). Specialized linkage software programs such as AutoMatch and Link Plus are used to perform the linkages. For those cancer registries unable to afford a data linkage program, the CDC offers Link Plus for free on their website. The objective of this presentation is to explore the variety of reasons to link a database with cancer registry files. Additionally, the presentation will illustrate the value of data linkages in increasing the quality of cancer registry and study data in order to assist in the goal of increased cancer control. The stated objectives will be achieved by offering real-world examples of the effectiveness of linking population-based cancer registry databases with other sources. Potential examples include: investigators linking their study cohort to a cancer registry database to determine cancer diagnoses and burden among their cohort; the cancer registry itself utilizing the linkage process to update the vital status and date of last contact for patients in their database; evaluating the effectiveness of cancer screening programs; and using linkages for pharmacoepidemiology safety surveillance studies. If used properly, data linkages can be effective in increasing the quality of a cancer registry's data, allowing researchers to have a better understanding of cancer burden in their cohorts, and helping to determine if cancer screening efforts, especially among lower-income persons, are effective.