The usefulness and reliability of information provided by cancer registries (CRs) depends on the quality of the data collected. Therefore, in 2014, a Working Group was set up with the task of establishing a comprehensive and standardised list of data quality checks to be adopted by European CRs and European projects. The Working Group has produced a proposal for 'One common procedure for data quality checks for European cancer registries' (first release 2014, last update 2018, will be updated by the end of 2021). The proposal included agreements on case definition, variables to be collected, and their format and internal consistency rules.

In order to enable cancer registries to perform data quality checks and to test the adherence of their data to the required format of the ENCR-JRC data calls, starting from 2015 the JRC has been developing the JRC–ENCR Cancer Registries Data Quality Check Software (QCS).

The present Version 2.0 of the JRC-ENCR QCS is based on the 2021 data call protocol, and the experience gathered after validating over 30 million cases from around 150 population-based cancer registries in 35 European Countries with previous JRC-ENCR QCS versions. In addition, feedback from European cancer registries and institutions was taken into account for the improvement of the JRC-ENCR QCS.

In addition to the Quality Check Software version 2.0 released in November 2021, the new Quality Check Software Kit now includes the CVS Data Layout Converter (QCS Buddy 1.0) created in order to assist users (with Windows operating systems) in the creation of incidence files to be checked with the QCS according to the latest ENCR-JRC call for data protocol.

Version 2.0 of the JRC-ENCR Quality Check Software, which replaces version 1.8.1 distributed in 2019, includes the following features:

• checks on the data files format (for incidence, mortality, lifetables and population) and on variables names and order according to the data call protocol (see section 3.1.1 below)
• verification of variables' formats and values
• cross checks among variables (internal consistency)
• check of multiple primary tumours

In comparison to version 1.8.1, the 2021 version 2.0 release of the software includes the following changes and enhancements:

• ability to be run, in addition to the 2021 ENCR-JRC call for data protocol, also on the previous (2015) call for data protocol
• creation of a separate software, the JRC CSV Data layout converter (QCS Buddy) that will assist users in the preparation of the file to be run by the QCS
• new consistency check between topography, TNM Edition, TNM, and stage introduced
• new consistency check between topography, TNM Edition, TNM, stage and morphology introduced
• new consistency check between TNM edition and pM introduced
• new check on TNM edition value introduced
• All TNM Checks: update to 8th edition (6th and 7th editions were already included in QCS version 1.8.1)
• updated morphology families used by checks involving TNM and morphology according to the ICD-O-3.2 update
• updated morphology families used by the multiple primary tumour checks according to the ICD-O-3.2 update
• inclusion of behaviour 2 (in situ) and behaviour 1 (uncertain and unknown behaviour) urological tumours (C65-C68 ICD-O-3 codes) as well as behaviour 1 and behaviour 0 (benign tumours) central nervous systems tumours (C70-C72 and C751-C753) in the multiple primary tumour checks