R. Gazzarata, et al, “Developing an HL7 FHIR Implementation Guide for Rare Cancers: The IDEA4RC Project Experience”, Studies in Health Technology and Informatics, Volume 336: Opening the Personal Gate between Technology and Health Care, M. Giacomini et al. (Eds.) (2026). DOI: 10.3233/SHTI260511
abstract
Rare cancers data sharing and secondary use are hindered by low incidence, heterogeneous pathways, and fragmented sources. The IDEA4RC project addresses these issues by creating a federated ecosystem for harmonized data exchange across European Centers of Excellence.
This paper presents the IDEA4RC HL7 FHIR Implementation Guide (IG), which operationalizes the IDEA4RC common data model—organizing 279 clinical variables across 19 entities—into computable specifications for semantic and computational interoperability. The IDEA4RC HL7 FHIR IG combines logical models, constrained resource profiles, terminology bindings, and grouped ConceptMaps that document traceable mappings from model entities (e.g., Cancer Episode) to FHIR profiles.
The data model was developed within IDEA4RC, a multi-stakeholder European consortium, and co-designed with clinical partners. While the model itself is described in a separate paper, this article reports its technical translation into a computable FHIR Implementation Guide (IG). This work was primarily led by technological partners, with clinicians contributing to concept interpretation and providing feedback during the early stages of implementation.
Compared to existing initiatives such as mCODE, our approach strengthens longitudinal and episode-based representation needed for European research contexts. The resulting IDEA4RC HL7 FHIR IG underpins robust rare cancer data sharing and paves the way for broader harmonization across oncology standards, including future convergence with the HL7 Cancer Common Model Project.
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