контекст:
For people who have none of the increased risks described above, screening should start at age 50. Colonoscopy every 10 years is preferred. Alternatives include annual stool testing and/or flexible sigmoidoscopy every 5 years. If stool testing is done, 3 stools should be tested each year. Stool should not be tested during a rectal examination. Barium enema every 5 years is the least preferred option.

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