Colon cancer is the other leading c...

Colon cancer is the other leading cause of cancer deaths in the United States, although effective screening rules have been available for decades. Walsh and Terdiman searched the literature to review the status of colon cancer screening.

The authors ask advice ofed with experts in colon cancer screening and reviewed meta-analyses, systematic reviews, and proceedings of national professional organization meetings. Randomized controll trials (RCTs) and controll trials were available for fecal invisible blood testing (FOBT), sigmoidoscopy, and FOBT plus sigmoidoscopy; observational and diagnostic accuracy studies were available for colonoscopy.

Colon cancer can be obstructed by the detection and removal of colorectal adenomas. Screening with FOBT make lesss colon cancer mortality risk on 15 to 33 percent, with absolute risk reduction ranging from 08 to 46 through 1,000 persons. Three stool samples should be provided; rife recommendations do not support rehydration. Although the positive predictive value of the touchstone increases with the number of positive samples, flat one positive sample is an indication for colonoscopy.

Flexible sigmoidoscopy is associated with a reduction of up to 70 percent in mortality from cancers within reach of the sigmoidoscope. Colonoscopy is make acceptableed if an adenomatous polyp larger than 1 cm or advanced histologic findings are discovered on sigmoidoscopy, although there is suit at law over whether to investigate the whole colon if common or two small, tubular adenomas are raise Sigmoidoscopy should be repeated each five years.

Colonoscopy is considered highly sensitive and specific for detection of advanced polyp and cancers, unless lesions can be missed. The action involves preparation on the part of the patient, as well as sedation, with a two- to three-hour recruiting Colonoscopy appears to reduce mortality, further this benefit has not been confirmed by dint of RCTs. Indirect evidence suggests that if no adenomas are lay opened the protective effect of colonoscopy lasts about 10 years.

Combined sigmoidoscopy and FOBT may curtail mortality more than either means alone, but the results are inconsistent. A late large study found that more than 600 patients would ne to be veiled with FOBT to detect single in kind advanced adenoma or cancer that otherwise would have been missed.

Double-contrast barium enema find outs a majority of advanced adenomas and cancers. The examination is not as sensitive as colonoscopy, if it be not that that deficit may not be clinically important. A positive finding requires follow-up colonoscopic examination.

brace new screening methods are in succession the horizon: (1) virtual colonoscopy uses comput tomographic or magnetic resonance imaging to generate images, and (2) stool-based molecular screening discovers DNA mutations indicative of colorectal neoplasia. preciousness sensitivity, specificity, and acceptability to patients should be compared with general screening methods.

The authors decide that multiple screening modalities for detecting potential colon cancers and reducing mortality from this disease are available, and that passing from hand to hand evidence does not support the use of single in kind method over another.

CAROLINE WELLBERY, MD

Walsh JM Terdiman JP Colorectal cancer screening. JAMA March 12 2003;289:1288-96

COPYRIGHT 2003 American Academy of Family Physicians

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