Long-term Adherence to Colorectal Cancer Screening; 5-Year Results from the Systems of Support to Increase Colorectal Cancer Screening Trial

Colorectal cancer (CRC) is the second-leading cause of cancer deaths. Mortality could be rapidly reduced through higher uptake and adherence to CRC screening. Information on long-term screening adherence comes from organized programs that lack a comparison group. Objective: Systems of Support to Increase Colorectal Cancer Screening 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 (UC) intervention-arm patients would have more time in compliance with CRC screening guidelines over 5 years. Methods: The setting was an integrated healthcare organization in Washington State. UC included patient-centered medical home with clinic-based strategies to increase screening. Participants included 4675 individuals initially aged 50–74, not current for CRC screening. Intervention arms combined were compared to UC. The primary outcome was the percent of time covered for CRC screening over 5 years of follow-up. Screening tests contributed covered time based on national guidelines for screening intervals. All participants contributed data, but were censored at disenrollment, death, age 76, or CRC diagnosis. Interventions: Patients were randomly assigned to receive UC, or one of three stepped care interventions: 1. Mailings including mailed fecal tests, a call-in number if colonoscopy or sigmoidoscopy was preferred; 2. Mailings plus brief telephone assistance; 3. Mailings and telephone assistance plus nurse navigation. In year 3, intervention group participants still CRC screening-eligible were randomized to stopped or continued mailed interventions only. Results: Compared to UC, intervention participants had 31% more time not in need of CRC testing (adjusted rate ratio, weighted for exposure time 1.31 [1.25–1.37], 47.2% vs. 62.0% covered time) over 5 years. Fecal testing was responsible for almost all additional covered time. Compared to intervention participants, UC individuals were more likely never to have completed any CRC testing over 5 years (17.4% vs. 10.3%, net difference 7.2%, P < 0.001) Conclusions: An organized mail and phone program led to increased CRC screening adherence over 5 years, mainly because of regular fecal testing uptake.