Population Health Colorectal Cancer Screening Strategies in Adults Aged 45 to 49 Years

Importance Colorectal cancer screening is now recommended at age 45 years for average-risk individuals; however, optimal outreach strategies to screen younger adults are unknown. Objective To determine the most effective population health outreach strategy to promote colorectal cancer screening in adults aged 45 to 49 years. Design, Setting, and Participants Randomized clinical trial with 20 509 participants conducted in a large health system (UCLA Health). Primary care patients aged 45 to 49 years at average risk for colorectal cancer were randomized 1:1:1:1 to 1 of 4 outreach strategies. The trial ran May 2, 2022, to May 13, 2022, with follow-up through November 13, 2022. Interventions Colorectal cancer screening via 1 of 4 strategies: (1) fecal immunochemical test (FIT)–only active choice; (2) colonoscopy-only active choice; (3) dual-modality (FIT or colonoscopy) active choice; and (4) usual care default mailed FIT outreach. Main Outcome and Measures Primary outcome was participation in screening (FIT or colonoscopy) at 6 months. Secondary outcome was screening modality completed. Results Among 20 509 participants (53.9% female, 4.2% Black and 50.8% non-Hispanic White; mean [SD] age, 47.4 [1.5] years), 3816 (18.6%) underwent screening. Participation was significantly lower in each of the 3 active choice groups (FIT only, 841 of 5131 [16.4%; rate difference, −9.8%; 95% CI, −11.3% to −8.2%]; colonoscopy only, 743 of 5127 [14.5%; rate difference, −11.7%; 95% CI, −13.2% to −10.1%]; dual-modality FIT or colonoscopy, 890 of 5125 [17.4%; rate difference, −8.9%; 95% CI, −10.5% to −7.4%]) than in the usual care default mailed FIT group (1342 of 5126 [26.2%]; all P < .001). Participants offered dual-modality active choice more likely completed any screening than those offered a single active choice modality (17.4% [dual-modality FIT or colonoscopy] vs 15.4% [FIT only and colonoscopy only combined]; rate difference, −1.8%; 95% CI, −3.0% to −0.1%; P = .004]). Among 5125 participants offered a choice between 2 modalities (dual-modality active choice FIT or colonoscopy), colonoscopy was more common than FIT (616 [12.0%] vs 288 [5.6%]; rate difference, −6.4%; 95% CI, −7.5% to −5.3%; P < .001). There was notable crossover in the FIT-only groups to colonoscopy (502 of 5131 [9.8%; FIT-only active choice] and 501 of 5126 [9.8%; usual care default mailed FIT]). Crossover from colonoscopy to FIT was modest (137 of 5127 [2.7%; colonoscopy-only active choice]). Conclusions and Relevance In this randomized clinical trial, 3 different active choice interventions had lower colorectal cancer screening completion rates among individuals aged 45 to 49 years compared with usual care. Trial Registration ClinicalTrials.gov Identifier: NCT05275530