[Estimated impact of the current colorectal screening program in France]

Colorectal cancer is the third most common cancer and the second most deadly in France. A Cochrane meta-analysis has confirmed the benefits of colorectal cancer screening. A nationwide colorectal screening program was set up in France in 2009 for medium-risk, asymptomatic people aged 50 to 74 years. It has been based, since 2015, on the Fecal Immunochemical Test. The participation rate for 2016-2017 was 34%, which is lower than the European objectives. The objective of this study was to evaluate the impact of the program at the current participation rate and at rates of 45% and 65%.

The epidemiological impact of the program was estimated from the results of an individual simulation model adapted from the Microsimulation Screening Analysis Colon model, calibrated and transposed to the French context. An initial analysis was conducted to estimate the individual impact of screening and a second for the entire eligible population, at various participation rates.

The test is associated with a lifetime reduction in the risk of colorectal cancer of 24% for men and 21% for women, and a reduction in the risk of death from colorectal cancer of 51% and 43% respectively. At the current level of participation, the program reduces incidence by 5% and mortality by 14% compared to no organized screening. The impact would be reduced by an additional 3% and 8% for participation rates of 45% and 65% respectively. Similarly, mortality would decrease by an additional 8% and 22%.

These results confirm that in a population at medium risk for colorectal cancer, the organised programme is an effective strategy for reducing its incidence. They also confirm that the achievement of European objectives remains a key issue for improving the effectiveness of organized screening. An evolution of immunological test delivery modalities could help to achieve these participation objectives.