Screening for colorectal cancer in adults at average risk: a summary of the evidence for the U.S. Preventive Services Task Force.
OBJECTIVE
To assess the effectiveness of different colorectal cancer screening tests for adults at average risk.


METHODS
Recent systematic reviews; Guide to Clinical Preventive Services, 2nd edition; and focused searches of MEDLINE from 1966 through September 2001. The authors also conducted hand searches, reviewed bibliographies, and consulted context experts to ensure completeness.


METHODS
When available, the most recent high-quality systematic review was used to identify relevant articles. This review was then supplemented with a MEDLINE search for more recent articles.


METHODS
One reviewer abstracted information from the final set of studies into evidence tables, and a second reviewer checked the tables for accuracy. Discrepancies were resolved by consensus.


RESULTS
For average-risk adults older than 50 years of age, evidence from multiple well-conducted randomized trials supported the effectiveness of fecal occult blood testing in reducing colorectal cancer incidence and mortality rates compared with no screening. Data from well-conducted case-control studies supported the effectiveness of sigmoidoscopy and possibly colonoscopy in reducing colon cancer incidence and mortality rates. A nonrandomized, controlled trial examining colorectal cancer mortality rates and randomized trials examining diagnostic yield supported the use of fecal occult blood testing plus sigmoidoscopy. The effectiveness of barium enema is unclear. Data are insufficient to support a definitive determination of the most effective screening strategy.


CONCLUSIONS
Colorectal cancer screening reduces death from colorectal cancer and can decrease the incidence of disease through removal of adenomatous polyps. Several available screening options seem to be effective, but the single best screening approach cannot be determined because data are insufficient.
University of North Carolina at Chapel Hill, Department of Medicine and Cecil Sheps Center for Health Services Research, 5039 Old Clinic Building, CB #7110, Chapel Hill, NC 27599, USA.
Michael
M
Pignone
Melissa
M
Rich
Steven M
SM
Teutsch
Alfred O
AO
Berg
Kathleen N
KN
Lohr
D000367:Age Factors; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000517:prevention & control*; D004733:Enema; D019317:Evidence-Based Medicine; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000009:adverse effects / Q000191:economics / Q000592:standards; D008875:Middle Aged; D009780:Occult Blood; D010808:Physical Examination; D012007:Rectum; D012812:Sigmoidoscopy; D013997:Time Factors