Background: National guideline groups recommend screening and discussion of screening options for persons at average risk for colorectal cancer (CRC). However, emerging evidence suggests that CRC screening is simultaneously underused, overused, and misused and that adequate patient-provider discussions about screening are infrequent.
Purpose: To summarize evidence on factors that influence CRC screening and strategies that increase the appropriate use and quality of CRC screening and CRC screening discussions.
Data sources: MEDLINE, the Cochrane Library, and the Cochrane Central Register of Controlled Trials were searched for English-language publications describing studies conducted in the United States from January 1998 through September 2009.
Study selection: Two reviewers independently selected studies that addressed the study questions and met eligibility criteria.
Data extraction: Information on study design, setting, intervention, outcomes, and quality were extracted by one reviewer and double-checked by another. Reviewers assigned a strength-of-evidence grade for intervention categories by using criteria plus a consensus process.
Data synthesis: Reviewers found evidence of simultaneous underuse, overuse, and misuse of CRC screening as well as inadequate clinical discussions about CRC screening. Several patient-level factors were independently associated with lower screening rates, including having low income or less education, being uninsured, being Hispanic or Asian, being less acculturated into the United States, or having limited access to care. Evidence that interventions that included patient reminders or one-on-one interactions (that is, between patients and nonphysician clinic staff), eliminated structural barriers (for example, simplifying access to fecal occult blood test cards), or made system-level changes (for example, using systematic screening as opposed to opportunistic screening) were effective in enhancing use of CRC screening was strong. Evidence on how best to enhance discussions about CRC screening options is limited. No studies focused on reducing overuse, and very few focused on misuse.
Limitations: Reporting and publication bias may have affected our findings. The independent effect of individual elements of multicomponent interventions was often uncertain.
Conclusion: Although CRC screening is underused overall, important problems of overuse and misuse also exist. System- and policy-level interventions that target vulnerable populations are needed to reduce underuse. Interventions aimed at reducing barriers by making the screening process easier are likely to be effective. Studies aimed at reducing overuse and misuse and at enhancing the quality and frequency of discussions about CRC screening options are needed.
Primary funding source: Agency for Healthcare Research and Quality.