[Colorectal cancer screening program : Test completion rate and follow-up results after selective mailing of the test kit, based on likelihood of participation]

Abstract

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.

Keywords: Colonoscopy completion rate; Colorectal cancer screening; Dépistage du cancer colorectal; Envoi postal du kit de test; Mailing of the test kit; Taux de réalisation de la coloscopie; Taux de réalisation du test; Test completion rate.