The major task of a population-based Cancer Registry (CR) is the identification of risk groups and factors. This analysis makes use of data about the social background of the population. The integration of that data is not intended for the routine processes at the CR. Therefore, this process must be performed by data warehouse experts that results in high cost. This paper proposes an approach, which allows epidemiologists and physicians at the CR to realize this ad hoc data integration on their own. We use model driven software design (MDSD) with a domain specific language (DSL), which allows the epidemiologists and physicians to describe the data to be integrated in a known language. This description or rather model is used to create an extension of the existing data pool and a web service and web application for data integration. The end user can do the integration on his/her own which results in a very cost-efficient way of ad hoc data integration.