Article Title

Systems of Support to Increase Colorectal Cancer (CRC) Screening –– A Randomized Trial to Increase Long-Term Adherence to CRC Screening: Time in Compliance Over 5 Years

Publication Date



cancer, health promotion, prevention, screening, clinical trials


Background: Colorectal cancer (CRC) is the second-leading cause of cancer deaths. Morbidity and mortality could be rapidly reduced through higher uptake and adherence to CRC screening. Information on longer-term screening adherence comes from organized programs that lack a comparison group. Systems of Support to Increase Colorectal Cancer Screening and Follow-Up (SOS) is an ongoing trial testing a centralized mailed and phone-based program to increase long-term CRC screening adherence. We hypothesized that, compared to usual care, intervention-arm patients would have more time in compliance with CRC screening guidelines over 5 years.

Methods: Design: Individual randomized controlled trial. Setting: Integrated health care organization in Washington State. Usual care included patient-centered medical home and clinic-based interventions to increase CRC screening. Participants: 4,675 individuals initially aged 50–74, without CRC or first-degree relative with CRC before age 60, no inflammatory bowel disease, no life-limiting disease, and not current for CRC screening. All participants contributed data but were censored at disenrollment, death, age 76 or diagnosis of CRC. Interventions: Included a mailed pamphlet on CRC screening choices, a call-in number if colonoscopy was preferred and mailed fecal tests for those not choosing colonoscopy. Patients were randomly assigned in years 1 and 2 to receive this only, this plus brief telephone assistance, or both mailings and assistance and nurse navigation for those still unscreened. In year 3, intervention group participants still CRC screening-eligible were randomized to stopped or continued mailed interventions in years 3 and 5. Primary outcome (a priori): The percent of time covered for CRC screening testing over 5 years (2008–2014). Screening tests contributed covered time based on national guidelines for screening intervals (fecal tests annually, sigmoidoscopy 5 years, colonoscopy 10 years).

Results: On average over 5 years, intervention participants had 224 more days of covered time, or 31% more time not in need of CRC testing (rate ratio, weighted for exposure time and adjusted relative risk 1.31 (1.25, 1.37). Fecal testing was responsible for almost all additional covered time.

Conclusion: An organized mail and phone program led to increased CRC screening adherence over 5 years, mainly because of regular fecal testing uptake.