OBJECTIVES: This study analyzed the potential of big data sets for health care research. Treatment patterns and medical care of oncological patients with thrombosis and the associated prescription of anticoagulation according to German guidelines were analyzed. METHODS: A nationally representative sample of 4.1 million (5.5 %) statutory health insured (SHI) persons was drawn from a database of 70 German SHI providers. The database contains information on demographics, both inpatient and outpatient care, on medication, and costs. Thereof, the retrospective analysis (2011-2016) defined demographical key figures, comorbidities and resource use to depict actual patterns of cancer treatment. Oncological patients were identified using coded diagnoses (ICD-10-GM) and outpatient prescriptions of anticoagulation (ATC Codes). The observation period of the study population was one year. RESULTS: