Level of evidence*	Clinical implications
A	FOBT performed every two years is effective in reducing colorectal cancer mortality but less so than annual testing.
A	FOBT reduces the incidence of colorectal cancer.
B	Barium enema sensitivity is lower than previously estimated.
B	Colonoscopy is more accurate than flexible sigmoidoscopy and
	FOBT for detecting colorectal neoplasia, but the implications for screening policy are unclear.
B	DNA stool test and virtual colonoscopy show early promise for
	detection of colorectal neoplasia, but further research is required.
A	Increased fiber intake does not prevent recurrent colorectal adenomas in middle-aged adults.
A	Calcium supplements reduce the risk of recurrent colorectal adenomas.
A	NSAIDs, including COX-2 inhibitors, reduce the risk of adenomas in patients with high-risk familial syndromes.