Importance: Colorectal cancer screening (CRC) is recommended by all major US medical organizations but remains underused.
Objective: To identify interventions associated with increasing CRC screening rates and their effect sizes.
Data sources: PubMed, Cumulative Index to Nursing and Allied Health Literature, the Cochrane Library, and ClinicalTrials.gov were searched from January 1, 1996, to August 31, 2017. Key search terms included colorectal cancer and screening.
Study selection: Randomized clinical trials of US-based interventions in clinical settings designed to improve CRC screening test completion in average-risk adults.
Data extraction and synthesis: At least 2 investigators independently extracted data and appraised each study's risk of bias. Where sufficient data were available, random-effects meta-analysis was used to obtain either a pooled risk ratio (RR) or risk difference (RD) for screening completion for each type of intervention.
Main outcomes and measures: The main outcome was completion of CRC screening. Examination included interventions to increase completion of (1) initial CRC screening by any recommended modality, (2) colonoscopy after an abnormal initial screening test result, and (3) continued rounds of annual fecal blood tests (FBTs).
Results: The main review included 73 randomized clinical trials comprising 366 766 patients at low or medium risk of bias. Interventions that were associated with increased CRC screening completion rates compared with usual care included FBT outreach (RR, 2.26; 95% CI, 1.81-2.81; RD, 22%; 95% CI, 17%-27%), patient navigation (RR, 2.01; 95% CI, 1.64-2.46; RD, 18%; 95% CI, 13%-23%), patient education (RR, 1.20; 95% CI, 1.06-1.36; RD, 4%; 95% CI, 1%-6%), patient reminders (RR, 1.20; 95% CI, 1.02-1.41; RD, 3%; 95% CI, 0%-5%), clinician interventions of academic detailing (RD, 10%; 95% CI, 3%-17%), and clinician reminders (RD, 13%; 95% CI, 8%-19%). Combinations of interventions (clinician interventions or navigation added to FBT outreach) were associated with greater increases than single components (RR, 1.18; 95% CI, 1.09-1.29; RD, 7%; 95% CI, 3%-11%). Repeated mailed FBTs with navigation were associated with increased annual FBT completion (RR, 2.09; 95% CI, 1.91-2.29; RD, 39%; 95% CI, 29%-49%). Patient navigation was not associated with colonoscopy completion after an initial abnormal screening test result (RR, 1.21; 95% CI, 0.92-1.60; RD, 14%; 95% CI, 0%-29%).
Conclusions and relevance: Fecal blood test outreach and patient navigation, particularly in the context of multicomponent interventions, were associated with increased CRC screening rates in US trials. Fecal blood test outreach should be incorporated into population-based screening programs. More research is needed on interventions to increase adherence to continued FBTs, follow-up of abnormal initial screening test results, and cost-effectiveness and other implementation barriers for more intensive interventions, such as navigation.