Behavioral Interventions Improve Mailed Colorectal Cancer Screening Among Overdue Patients in a Randomized Trial

Mailed fecal immunochemical testing (FIT) can boost colorectal cancer screening (CRC) rates, but response rates remain limited. We evaluated if behavioral interventions increased response rates. This pragmatic randomized trial with a 2x2x2 factorial design included primary care patients aged 50-74 who were overdue for CRC screening. Patients were randomized 1:1 to receive a health system branded blue box or a standard envelope. Patients were concurrently randomized 1:1 to receive or not receive text reminders. Patients were also concurrently randomized 1:1 to receive a reminder letter. The primary outcome was the proportion who completed a FIT within 4 months. Among 5,244 patients included, mean age was 59.6 (SD 7.3); 35.8% were Black and 53% were White. At four months, 17.8% (95% CI, 16.3 - 19.2%) who received the box compared to 18.0% (95% CI, 16.5 - 19.5%) who received the standard envelope completed FIT, an absolute difference of -0.2% (95% CI, -2.3 - 1.9%; p=0.85). Among those who received text messaging, 21.2% (95% CI, 19.6 - 22.8%) completed FIT compared to 14.6% (95% CI, 13.2 - 15.9%) of those who did not, an absolute difference of 6.6% (95% CI: 4.6 - 8.7%; p < 0.001). Among those that received the mailed reminder, 20.3% (95% CI, 18.7 - 21.8%) completed FIT compared to 15.5% (95% CI, 14.1 - 16.9%) of those who did not, an absolute difference of 4.8% (95% CI: 2.7 - 6.9%; p < 0.001). Behaviorally-informed text messaging and mailed reminders significantly increased screening completion, but the health system branded box did not increase response rates.