A Centralized Program with Stepped Support Increases Adherence to Colorectal Cancer Screening Over 9 Years: a Randomized Trial

Background: Screening over many years is required to optimize colorectal cancer (CRC) outcomes.

Objective: To evaluate the effect of a CRC screening intervention on adherence to CRC screening over 9 years.

Design: Randomized trial.

Setting: Integrated health care system in Washington state.

Participants: Between August 2008 and November 2009, 4653 adults in a Washington state integrated health care system aged 50-74 due for CRC screening were randomized to usual care (UC; N =1163) or UC plus study interventions (interventions: N = 3490).

Interventions: Years 1 and 2: (arm 1) UC or this plus study interventions; (arm 2) mailed fecal tests or information on scheduling colonoscopy; (arm 3) mailings plus brief telephone assistance; or (arm 4) mailings and assistance plus nurse navigation. In year 3, stepped-intensity participants (arms 2, 3, and 4 combined) still eligible for screening were randomized to either stopped or continued interventions in years 3 and 5-9.

Main measures: Time in adherence to CRC testing over 9 years (covered time, primary outcome), and percent with no CRC testing in participants assigned to any intervention compared to UC only. Poisson regression models estimated incidence rate ratios for covered time, adjusting for patient characteristics and accounting for variable follow-up time.

Key results: Compared to UC, intervention participants had 21% more covered time over 9 years (57.5% vs. 69.1%; adjusted incidence rate ratio 1.21, 95% confidence interval 1.16-1.25, P<0.001). Fecal testing accounted for almost all additional covered time among intervention patients. Compared to UC, intervention participants were also more likely to have completed at least one CRC screening test over 9 years or until censorship (88.6% vs. 80.6%, P<0.001).

Conclusions: An outreach program that included mailed fecal tests and phone follow-up led to increased adherence to CRC testing and fewer age-eligible individuals without any CRC testing over 9 years.

Trial registration: Systems of Support (SOS) to Increase Colon Cancer Screening and Follow-up (SOS), NCT00697047, clinicaltrials.gov/ct2/show/NCT00697047.