IDEA4RC Data Model

The IDEA4RC data model is a clinician-aligned, oncology-focused common data model designed specifically for rare cancers, built by integrating and extending the most useful elements of OSIRIS, OMOP Oncology, and HL7 FHIR. Its purpose is to capture the full longitudinal cancer journey, diagnosis, staging, treatments, outcomes, and disease evolution, while remaining simple enough for clinical teams to understand and validate. Structurally, it is organized around patient-centric cancer episodes, which link diagnoses, metastatic patterns, staging events, surgical acts, systemic and radiotherapy treatments, and follow-up information in a coherent temporal chain. Semantically, it relies on standard vocabularies (SNOMED CT, ICD-O, TNM) via the OHDSI Athena repository to ensure interoperability across centres. The model serves a dual role: internally, it provides a consistent structure for quality checks, NLP extraction, and federated analytics; externally, it maintains explicit mappings to OMOP and FHIR so that data can be exchanged or reused without losing granularity. Overall, the IDEA4RC data model balances interoperability, real-world clinical usability, and analytic readiness in a way that existing models did not, enabling reliable rare-cancer research across heterogeneous European centres.