Bridging Data Silos in Oncology with Modular Software for Federated Analysis on FHIR: A Multisite Implementation Study (Preprint)

Abstract

BACKGROUND Real-world data (RWD) from sources like administrative claims, electronic health records, and cancer registries offer insights into patient populations beyond the tightly regulated environment of randomized controlled trials. To leverage this and to advance cancer research, six university hospitals in Bavaria have established a joint research IT infrastructure. OBJECTIVE This article aims to outline the design, implementation, and deployment of a modular data transformation pipeline that transforms oncological RWD into HL7 (Health Level 7) FHIR (Fast Healthcare Interoperability Resources) format and then into a tabular format in preparation for a federated analysis (FA) across the six BZKF university hospitals. METHODS To harness RWD effectively, we designed a pipeline to convert the oncological basic dataset (oBDS) into HL7 FHIR format and prepare it for federated analysis. The pipeline handles diverse IT infrastructures and systems while maintaining privacy by keeping data decentralized for analysis. To assess the functionality and validity of our implementation, we defined a cohort to address two specific medical research questions. We evaluated our findings by comparing the results of the FA with reports from the Bavarian Cancer Registry and the original data from local tumor documentation systems. RESULTS We conducted a federated analysis of 17,885 cancer cases from 2021/2022. Breast cancer was the most common diagnosis at three sites, prostate cancer ranked in the top two at four sites, and malignant melanoma was notably prevalent. Gender-specific trends showed larynx and esophagus cancers were more common in males, while breast and thyroid cancers were more frequent in females. Discrepancies between the Bavarian Cancer Registry and our data, such as higher rates of malignant melanoma (5 % vs. 11 %) and lower representation of colorectal cancers (13 % vs. 7 %) likely result from differences in the time periods analyzed (2019 vs. 2021/2022) and the scope of data sources used. The Bavarian Cancer Registry reports approximately three times more cancer cases than the six university hospitals alone. CONCLUSIONS The modular pipeline successfully transformed oncological RWD across six hospitals, and the federated approach preserved privacy while enabling comprehensive analysis. Future work will add support for recent oBDS versions, automate data quality checks, and integrate additional clinical data. Our findings highlight the potential of federated health data networks and lay the groundwork for future research that can leverage high-quality RWD, aiming to contribute valuable knowledge to the field of cancer research.