How does colonoscopy compare with fecal occult blood testing as a screening tool for colon cancer?

EVIDENCE-BASED ANSWER

No studies have directly compared colonoscopy with fecal occult blood testing (FOBT). Multiple screening trials have demonstrated that a primary strategy of 3-card home FOBT with follow-up colonoscopy for positive results is associated with a significant reduction in mortality from colorectal cancer (strength of recommendation [SOR]: A, based on systematic reviews of randomized and nonrandomized controlled trials). A single negative office-based digital FOBT does not decrease the likelihood of advanced neoplasia (SOR: B, based on a single prospective cohort study).

There are no publications of screening trials with colonoscopy, but the odds of dying from colorectal cancer are lower for patients undergoing colonoscopy compared with patients not having a colonoscopy (SOR: B, based on extrapolation from a case-control study). Both strategies are cost-effective (SOR: A, based on a systematic review of high-quality cost-effective analyses).

CLINICAL COMMENTARY
For those at average risk, consider patient preference, likelihood of adherence to follow-up, community resources

While a clear answer does not emerge for a preferred strategy for colorectal cancer screening between FOBT and colonoscopy, colorectal cancer causes a significant burden of suffering including death. Clinicians must find a systematic way to address colorectal cancer screening with their own patient populations, and find an effective way to determine whether their patients are at average or increased risk for colorectal cancer. For those at average risk, consider patient preference, likelihood of patient adherence to follow-up screening, and community resources as you and your patient try to find common ground. When discussing three-card home FOBT with patients, make them aware that positive test results will lead to colonoscopy.
Journal of Family Practice, Nov, 2005 by Bruce D. Boggs, Mary M. Stephens, Rick Wallace