Testing behavioral economics messages to increase non-responders' participation in organized colorectal cancer-screening programs: A randomized controlled trial.

This study aimed to evaluate the impact of behavioral economic-inspired messages on participation in colorectal cancer (CRC) screening programs. We conducted a randomized-controlled trial involving 11,505 non-responders to the CRC screening programs in Florence, Rome, and Turin in 2020. Participants aged 54-70 years were randomly assigned to four conditions. Individuals in the control conditions received a standard invitation letter while the three intervention groups included an additional paragraph featuring either i. normative feedback [F] message (giving feedback that invited subjects did not participate); ii. Minority norm [MN] message (only a minority did not participate); iii. F+ MN message (combining both messages). The primary outcome was the screening participation rate 90 days after the invitation was completed. A multivariate analysis was conducted adjusting for gender, age and birthplace. Overall, screening participation rates were 5.3% in the control condition, 7.0% in the F, 8.2% in the MN, and 7.4% in the F + MN arms (p = 0.002). Invited subjects in the MN arm were more likely to participate (adjusted Odds Ratio[aOR] = 1.38; 95% Confidence Interval [95%CI,1.13-1.68]), particularly those aged 54-59 years (aOR = 1.52; 95%CI:1.16-1.98), and 60-64 (aOR = 1.57; 95%CI:1.62-; 95%CI: 1.06-2.48). Additionally, individuals aged 60-64 invited in F and F + MN arms demonstrated a higher likelihood of participation (aOR for F arm = 1.60; 95%CI: 1.06-2.41; aOR for F + MN arm = 1.99; 95%CI: 1.35-2.92). The inclusion of MN and/or F messages in the invitation letter increased participation among previous non-responders <65 years. Behavioral economics is a promising area of interest for enhancing CRC screening participation. TRIAL REGISTRATION: ISRCTN registration number: ISRCTN11841256.