Risk stratification in fecal immunochemical test-based colorectal cancer screening: Public acceptance and experiences with tailored invitation intervals.

Objective: Risk stratification based on prior fecal Hemoglobin (f-Hb) concentrations offers potential to enhance the effectiveness of fecal immunochemical test (FIT)-based colorectal cancer (CRC) screening programs. Acceptance of tailored invitation intervals has not been assessed in individuals undergoing risk-stratified CRC screening. Methods: We conducted five semi-structured focus groups with participants from the Dutch risk-stratified CRC screening trial (PERFECT-FIT), to explore their experiences with tailored invitation intervals. Study participants included thirteen individuals assigned an extended (three-year) invitation interval and eleven individuals assigned a shorter (one-year) invitation interval based on their prior f-Hb concentration. Additionally, four individual interviews were conducted with individuals who had dropped out of the trial after being assigned a three-year interval. All data were collected between January and June 2023. Transcripts were thematically analyzed using ATLAS.ti. Results: Intensified screening was preferred over less intensive screening, driven by the perceived low burden of FIT-based screening and a desire to detect lesions as early as possible. Shorter intervals were therefore readily accepted. Extended intervals raised concerns about missed lesions but were largely accepted as individuals felt reassured by their low-risk classification. Individuals were less concerned about risk-stratified intervals when implemented nationwide, trusting the provider would only implement these after scientific evaluation of potential risks. Conclusions: Our findings support the acceptance of tailored invitation intervals within a population-based CRC screening program. This acceptance appears to be influenced by participants' high trust in the screening provider, emphasizing the importance of maintaining this trust. Clear communication of a changing screening approach, especially the reporting of negative FIT-results, may facilitate the transition from uniform to risk-stratified screening.