Diseases like cancer are caused by a diversity of different factors interacting together, whose study requires a huge amount of data. Compiling this data is an expensive and time-consuming task that can be carried out in an easier, faster and more secure way with the support of Information and Communication Technologies (ICT). Nevertheless, the majority of epidemiologic studies are executed without this support of informatics or with basic tools that are developed by unqualified professionals. As a consequence, the integrity of the collected data cannot be assured, and the reliability of the studies is usually decreased. This work presents an ontology-based Information System for the development of multicenter epidemiologic studies on cancer that allows 1) collecting, storing and editing medical data from different hospitals and 2) reusing the
compiled data by means of their integration with data from other systems. This system has been
satisfactorily applied to an epidemiologic study of colorectal cancer in Galicia, Spain.