[Colorectal cancer screening program : Test completion rate and follow-up results after selective mailing of the test kit, based on likelihood of participation]. / Dépistage organisé du cancer colorectal : taux de réalisation du test et résultats du suivi après un envoi postal sélectif du kit de test, basé sur la probabilité de participation.

BACKGROUND: Even though theinterest of a Colorectal-Cancer Screening Program has been amply demonstrated, in French departments the participation rate (PR) seldom reaches 45%. In the absence of mass mailing, a strategy (S-1) consisting in mailing a test kit to people having made a request was implemented in 2015. In 2017, another mailing strategy (S-2), which consisted in sending the test kit only to people likely to take the test, was programmed. This study assesses the respective impact of these two strategies as compared to the standard approach (S-0). METHODS: The study included 254,113 (S-0), 4,130 (S-1) and 10,887 (S-2) people aged 50-74, targeted during the 2016-2017 campaign in Seine-Saint-Denis (France). S-0 persons received a 2nd reminder without a test-kit, while S-1 persons received, at their request, a mailed test kit. Without having made a request, S-2 persons the mailed test kit according to probability of participation (Proba) which was estimated a priori by the ratio between the sum total of index values (frequency of previous participation, date of most recent participation, age) and a theoretical maximum. Completion rates (test/colonoscopy) were compared 18 months after the last S-2 kit was sent. RESULTS: PR was highest in S-1 (S-0: 5.8%, S-1: 74.9%, S-2: 31.3%; p < 0.0001). In S-2, PR rose as Proba increased (Proba: ]0-30%], ]30-50%], ]50-75%], ]75-100%]; PR: 21.1%, 23.3%, 36.2%, 52.8% respectively; p < 0.05). Compared to the ≥70 years age-group, the 50-54 years age-group presented a lower PR in S-1 (65.9% vs. 85.1%; p < 0.05) whereas it presented a higher PR in S-0 (4.3% vs. 7.1%; p < 0.05) and in S-2 (23.2% vs. 54.5%; p < 0.05). All in all, colonoscopy completion rates were highest in S-1 (S-0: 62.2%, S-1: 80.0%, S-2: 65.0%; p < 0.001). CONCLUSION: Test-kit mailing without spontaneous request does not lead to an optimal level of participation, thereby highlighting a need to give thought to new and improved mobilization methods. The relatively pronounced participation of younger persons, who are not favored by present-day testing specifications, underscores the interest of a specific approach addressed to active people, who are less inclined than elderly individuals to regularly consult their attending physicians.

[Estimated impact of the current colorectal screening program in France]. / Estimation de l'impact du programme actuel de dépistage organisé du cancer colorectal.

BACKGROUND: 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%. METHODS: 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. RESULTS: 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%. CONCLUSION: 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.