Table 1. Effect of Screening Intervention on Reducing Mortality from Colorectal Cancera
| Fecal Occult Blood Test | Sigmoidoscopy | Digital Rectal Exam | Colonoscopy | |
| Study Design | RCTs | Case-control studies [1], RCTs in progress | Case-control studies | Case-control studies, RCTs in progress |
| Internal Validity | Good | Fair | Fair | Poor |
| Consistency | Good | Fair | Good | Poor |
| Magnitude of Effects | 15%–33% | About 60%–70% for left colon | No effect | About 60%–70% for left colon; uncertain for right colon |
| External Validity | Fair | Fair | Poor | Fair |
| RCT = randomized controlled trial. | ||||
| aThere are no data on the effect of other screening interventions (i.e., fecal occult blood test combined with sigmoidoscopy, barium enema, colonoscopy, computed tomographic colonography, and stool DNA mutation tests) on mortality from colorectal cancer. |
References
- Thiis-Evensen E, Hoff GS, Sauar J, et al.: Population-based surveillance by colonoscopy: effect on the incidence of colorectal cancer. Telemark Polyp Study I. Scand J Gastroenterol 34 (4): 414-20, 1999. [PUBMED Abstract]
