Optimising Colorectal Cancer Screening Participation -A Randomised Controlled Trial of Invitation Procedures

The aim of this study is to demonstrate the effectiveness of three and four-staged invitation procedures compared to two-staged procedures by combining pre-notifications and reminders. The RCT will be nested into the Danish colorectal cancer screening programme in the Central Denmark Region including men and women aged 50-74 years. Participants will consecutively be randomized into four arms in a 1:1 ratio. Intervention arm 1 will receive a pre-notification approximately ten days prior to intervention, invitation and one reminder (three-staged intervention), Intervention arm 2 will receive invitation, one reminder after 45 days and a second reminder three months after invitation (three-staged invitation procedure), Intervention arm 3 will receive pre-notification, invitation, reminder after 45 days and reminder after three months (four-staged invitation procedure). Finally, the forth arm will be a control group receiving usual care which invitation and one reminder 45 days after invitation (two-staged invitation procedure). Both pre-notifications and reminders are sent using digital mail.

The main out-come will be participation within 6 months after invitation.