Cancer is the second leading cause of death worldwide and in focus of epidemiological research. In Germany the cancer registration law stipulates an electronic report to the population-based cancer registry (PBCR). In this context the Comprehensive Cancer Centre Münster (CCCM) required a new concept to support the obligation to register cancer diseases. We analysed Hospital Information System (HIS) data structures related to cancer documentation and PBCR documents. Our main idea was to export available data items from the HIS and to convert them into the import format of the PBCR. We analysed HIS data and developed an XML-based converter to support an electronic reporting procedure. Using available HIS data can avoid redundant data entry and supports information workflow within the CCCM. HIS data can provide a secondary use beyond clinical routine in form of reporting, quality assurance and clinical research.