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Table 1. Effect of Screening Intervention on Reducing Mortality from Colorectal Cancera
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Fecal Occult Blood Test
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Sigmoidoscopy
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Digital Rectal Exam
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aThere are no data on the effect of other screening interventions (i.e., fecal occult blood test (FOBT)/sigmoidoscopy, barium enema, colonoscopy, computed tomographic [CT] colonography, and stool DNA mutation tests) on mortality from colorectal cancer.
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Study Design
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Randomized controlled trials |
Case-control studies, randomized controlled trials in progress |
Case-control studies |
Internal Validity
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Good |
Fair |
Fair |
Consistency
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Good |
Fair |
Good |
Magnitude of Effects
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15%–33% |
About 50% for left colon |
No effect |
External Validity
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Fair |
Poor |
Poor |
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