Two randomized controlled trials for colorectal cancer screening invitations developed using a behavioral science approach.

The effectiveness of behaviorally informed, targeted invitations to standard invitations and to no invitation (control arm, primary analysis) were compared in the context of an organized colorectal cancer (CRC) screening program. Two multi-arm, pragmatic randomized controlled trials in men (arms: male-specific, unisex, standard invitation, or no invitation) and in women (arms: unisex, standard invitation, or no invitation), were conducted in Ontario, Canada. Eligible persons aged 50-74, due for CRC screening, were randomized. Primary and secondary outcomes were completion of the guaiac fecal occult blood test (gFOBT) and uptake of any colorectal test, respectively, within 5 months of mailing. Impact of invitation type was assessed using logistic regression. Letters were mailed to 75,810 men and women; 38,673 males and 34,453 females were included in the analyses. Men who received the male-specific letter were most likely to screen with gFOBT compared to controls (odds ratio (OR) 7·24, 95% CI: 5·77, 9·09), followed by those receiving the unisex letter (OR 6·75, 95% CI: 5·37, 8·47) and the standard letter (OR 5·99, 95% CI: 4·76, 7·53). Women who received the unisex letter were most likely to be screened with gFOBT compared to controls (OR 7·07, 95% CI: 5·83, 8·59), followed by those receiving the standard letter (OR 6·76, 95% CI: 5·56, 8·21). In both trials, the findings were similar for the secondary outcome. Mailed invitations were effective for both men and women. With greater targeting using the behaviorally informed invitations, the magnitude of benefit relative to no invitation appeared to increase. (ClinicalTrials.gov, NCT02364895).