Opportunities and Challenges of Routine Healthcare Data in Oncological Health Services Research in Germany.

Routine healthcare data are becoming increasingly important for oncological health services research, as they enable population-based analyses based on routinely collected data. In particular, the combined use of different routine healthcare data sources, such as data from cancer registries in accordance with § 65c of the German Social Code, Book V, and claims data from statutory health insurance funds, offer significant potential for generating reliable evidence. The aim of this article is to describe practical experience related to data application, case selection, data preparation and analysis, and challenges and potential associated with the use of these routine healthcare data sources. To illustrate these insights, a research project funded by the Innovation Fund of the Joint Federal Committee is used as an example. As part of this intervention study evaluating a new model of care, an external routine healthcare data control arm was established based on cancer registry data and linked with claims data from statutory health insurance funds. Cancer registry data include valid information on diagnoses, tumor characteristics, treatment courses, and vital status and thus enable precise case selection; however, data completeness varies across regions. Claims data allow for the longitudinal and cross-sectoral analysis of treatment courses, but are limited in terms of clinical details, diagnostic accuracy, and therapy assignment. In particular, record linkage projects involving multiple routine healthcare data sources require time-consuming coordination and approval processes. Data preparation and analysis require detailed knowledge of the respective data structures and their limitations, as well as expertise in oncology and statistical methodology. The use of cancer registry and claims data linked at the person level enables comprehensive analyses of oncological long-term outcomes, care structures, and health economic aspects. At the same time, legal frameworks, data quality, and methodological complexity remain key challenges. With the introduction of the Health Data Utilization Act and the establishment of the Research Data Centre for Health, new opportunities are emerging for the use of routine healthcare data. The development of competencies among future users is a key prerequisite for generating valid and reliable research results.