The EUROCARE-3 database: methodology of data collection, standardisation, quality control and statistical analysis.

The EUROCARE database contains data on 6.5 million cancer patients diagnosed from 1978 to 1994 in populations covered by 67 cancer registries in 22 European countries. The quality-checked entries specify age, sex, diagnosis date, cancer site, morphology, microscopic confirmation and vital status, as well as containing broad indicators of stage. For EUROCARE-3, which refers to diagnoses from 1990 to 1994, 3389 cases with major data problems and 142,525 second or subsequent cancers were removed, leaving more than 2 million cases for analysis. From these data, observed and relative survival for each cancer site and country were calculated at 1, 3 and 5 years from diagnosis. Overall European survival for each cancer site and for all cancers combined were calculated combining country-specific survival figures. Overall, 1.1% of cases were lost to follow-up, 4.2% were known from death certificates only and 1.2% were known at autopsy only. The percentage of microscopically confirmed cases varied with cancer site and country, and was always higher in northern European countries. Comparison of quality indicators for the EUROCARE-3 database with earlier EUROCARE databases indicates that data quality and standardisation have improved.