Background: Real-world evidence provides valuable insights into cancer burden, presentation, and care variations. Through a large-scale federated approach, this study aims to explore patient characteristics and overall survival for eight cancers using data from 11 electronic health records and cancer registries from eight European countries, mapped to the Observational Medical Outcomes Partnership Common Data Model (OMOP-CDM).

Methods: Patients aged 18 years or older with a primary cancer diagnosis between 2000 and 2019 were included. Patients were followed from cancer diagnosis until death, database exit, or study end. Mortality data was sourced from linked national or subnational death registries for most databases. Patient characteristics, including comorbidities, and medication use, were summarised. Age-standardised overall survival (OS) at one, five, and ten years were calculated using the Kaplan-Meier method and stratified by cancer type, age group and sex.

Findings: There were 1,796,278 eligible cancer patients included with most diagnoses in individuals aged 60-79 years. Top comorbidities and medications were relatively consistent across databases, with certain variations observed by cancer type, possibly indicative of early cancer signs and risk factors. For instance, anaemia was frequent in colorectal (9% [HUS]-23% [IMASIS]; 791/8395-730/3141 individuals) and stomach cancers (10% [HUS]-34% [IMASIS]; 130/1277-225/670), while chronic obstructive pulmonary disease (18% [SIDIAP]-34% [HUVM], 5310/29,009-1039/3063) and pneumonia (5% [CPRD GOLD]-33% [UTARTU], 1904/34,990-1001/3063) were common in lung cancer patients. Breast and prostate cancers had the highest one, five and ten-year overall survival, with 5-year OS ranging from 76% [ECi]-85% [IMASIS] and 75% [HUVM]-83% [SIDIAP], respectively. Pancreatic cancer showed the lowest survival ranging from 3% [NCR]-25% [IMASIS] 5-year OS. Variations in cancer survival estimates were observed across data sources and countries.

Interpretation: Federated analysis of diverse European real-world databases, standardised to OMOP-CDM, offer a valuable benchmark for future cancer research, particularly in understanding prodromes and risk factors, often recorded in routinely collected healthcare data prior to cancer onset.

Funding: The European Health Data & Evidence Network has received funding from the Innovative Medicines Initiative 2 Joint Undertaking (JU) under grant agreement No 806968. The JU receives support from the European Union's Horizon 2020 research and innovation programme and the European Federation of Pharmaceutical Industries and Associations partners.