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Cancer Screening: One-on-One Education for Clients – Colorectal Cancer by Colonoscopy or Flexible Sigmoidoscopy


What the CPSTF Found

About The Systematic Review

The Task Force finding is based on evidence from a Community Guide systematic review published in 2008 (Baron et al., 0 studies, search period 1966-2004) combined with more recent evidence (4 studies, search period 2004-2008). The systematic review was conducted on behalf of the Task Force by a team of specialists in systematic review methods, and in research, practice, and policy related to cancer prevention and control. This finding updates and replaces the 2008 Task Force finding on Cancer Screening: One-On-One Education - Colorectal Cancer by Colonoscopy or Flexible Sigmoidoscopy [PDF - 331 kB].


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Summary of Results

Combined evidence from the original and updated reviews included four studies.

  • Screening by colonoscopy: range from 0 to 11 percentage points increase (2 study arms)
  • Screening by flexible sigmoidoscopy: no change reported (1 study arm)
  • Screening by any test (including FOBT): range from 1 to 11 percentage point increase (2 study arms)

Summary of Economic Evidence

The updated search for evidence included nine studies about breast cancer (5 studies), cervical cancer (1 study), or colorectal cancer (3 studies) screening. Monetary values are presented in 2009 U.S dollars.

  • Of the nine included studies, eight reported results from actual interventions and one used economic modeling.
    • The cost per additional screening ranged from $39 to $5,306, with a median of $534.
    • The most expensive intervention was the most resource intensive. Lay health advisors conducted three in-person home visits, made follow-up phone calls, and sent mailings that addressed barriers to screening.


Applicability of this intervention across different settings and populations was not assessed because the Task Force did not have enough information to determine if the intervention works.

Evidence Gaps

Each Community Preventive Services Task Force (Task Force) review identifies critical evidence gaps—areas where information is lacking. Evidence gaps can exist whether or not a recommendation is made. In cases when the Task Force finds insufficient evidence to determine whether an intervention strategy works, evidence gaps encourage researchers and program evaluators to conduct more effectiveness studies. When the Task Force recommends an intervention, evidence gaps highlight missing information that would help users determine if the intervention could meet their particular needs. For example, evidence may be needed to determine where the intervention will work, with which populations, how much it will cost to implement, whether it will provide adequate return on investment, or how users should structure or deliver the intervention to ensure effectiveness. Finally, evidence may be missing for outcomes different from those on which the Task Force recommendation is based.

Identified Evidence Gaps

The following outlines evidence gaps for one-on-one education to increase breast, cervical, or colorectal cancer screening.

  • What duration, dose, and intensity of one-on-one educational interventions are needed to be effective (Baron et al., 2008)?
  • What characteristics of "tailoring" contribute to its effect? Are there effects of tailoring channels (personal interaction, anonymous interaction)?
  • Does effectiveness of one-on-one education interventions vary according to whether or not education is delivered by a medical professional?
  • What are the incremental effects of adding intervention components to other interventions?
  • What influence do newer methods of communication (e.g., the Internet, e-mail, social media, automated interactive voice response, texting) have on intervention effectiveness?
  • What is the influence of health system factors on intervention effectiveness?
  • Are interventions effective for promoting colorectal cancer screening with methods other than FOBT?
  • Are interventions to promote colorectal cancer screening equally effective when specific to one type of test as they are when addressing colorectal cancer screening more generally?


Baron RC, Rimer BK, Breslow RA, et al. Client-directed interventions to increase community demand for breast, cervical, and colorectal cancer screening: a systematic review. Am J Prev Med 2008;35(1S):S34–S55.

Study Characteristics

  • In addition to white participants, studies included Asian-American participants, and participants with low socioeconomic status.
  • Both studies were conducted in the U.S., and neither specified inclusion of rural populations.
  • Studies included participants 50 years and older.