Rationale for organized Colorectal cancer screening programs.

Colorectal cancer (CRC) is a major health problem and it is expected that the number of persons diagnosed with CRC and CRC-related deaths will continue to increase. However, recent years have shown reductions in CRC incidence and mortality particularly among individuals aged 50 years and older which can be attributed to screening, improvements in patients' management, closer adherence to treatment guideline recommendations and a higher utilization of curative surgery, chemotherapy and radiotherapy. The International Agency for Research on Cancer has concluded that there has been sufficient evidence that biennially screening using a stool-test or once-only endoscopy screening reduces CRC-related mortality. In Europe, between 2008 and 2018, nine countries have successfully implemented a population-based organized program and another six are in the roll-out phase. Population-based organized programs show higher screening participation rates and lower lack of compliance to follow-up testing after a positive screen test compared to opportunistic screening. Moreover, organized programs aim to provide high quality screening thereby reducing the risk of the harms of screening, including over-screening, and complications of screening, and poor follow-up of those who test positive. We describe how population-based organized CRC screening programs are preferred, since they reflect a more appropriate utilization of available resources, reduce inequities in access, and can integrate interventions addressing barriers to screening at the individual and health system levels.