Introduction
In France, the government has decided, through the Act of 30 June 2025, to entrust the National Cancer Institute (INCa) with the implementation of a national cancer registry, centralising population-based data on cancer epidemiology and cancer care. The objectives are to identify and collect cancer cases nationwide, gather relevant data, and make expert-validated, linked and pseudonymised datasets available for secondary use.
 
Methods
The national cancer registry is based on a progressively implemented multisource case-reporting system:
The Cancer Cohort (CC): extraction from the French National Health Data System (SNDS) since 2010, identifying individuals whose healthcare utilisation suggests a cancer diagnosis (hospitalisation, long-term disease status, radiotherapy, anticancer drugs).
Local cancer registry data: used to complement, confirm and characterise cancers (topography, morphology, behaviour) within registry-covered areas.

Clinical care documents: including cancer screening reports, pathology reports, molecular genetics results, and multidisciplinary tumour board reports. 
Direct linkage using the national personal identification number (NIR) will be performed as soon as possible; otherwise, indirect linkage based on shared variables across data sources will be applied.
 
The resulting health data warehouse is accessible on a project basis, subject to regulatory approval. Open data and data visualisation tools are also being developed to provide indicators and aggregated datasets to public decision-makers and national agencies.
 
Results
The current health data warehouse includes Cancer Cohort data covering approximately 13 million incident and prevalent cancer cases from 2010 to 2023. Local cancer registry data from 2010 to 2021 have been integrated through indirect linkage, with matching rates of 95% for solid tumours.
Additional data sources are being progressively incorporated. INCa is currently implementing automated and standardised data flows for shared oncology medical records, a common information system for all local cancer registries, and national data collection systems for cancer screening.
Around thirty research projects have already been completed or are ongoing using the Cancer Cohort, which has been available for secondary use since 2023.
 
Conclusion
The multisource data collection and cross-validation of registry data (gold standard) with Cancer Cohort data within registry-covered areas aim to improve cancer case qualification across the entire national territory. These high-quality oncology data will serve as reference datasets in the context of establishing the national data access body in France.