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Occult Blood Screening Reduces Risk for Colorectal Cancer

Results of randomized trials have shown that regular fecal occult blood testing (FOBT) can reduce colorectal cancer mortality by increasing the detection and removal of early cancers. But screening also offers another potential benefit: preventing colorectal malignancy through detection and removal of precancerous lesions.

Researchers explored this possibility in an update from a previously published trial of more than 40,000 men and women aged 50 to 80 (JW Jun 1 1993, p. 81, accession number 930521001, and N Engl J Med 1993; 328:1365; Erratum, N Engl J Med 1993; 329:672). Participants were assigned to receive annual FOBT screening, biennial screening, or usual care; positive FOBT was followed by colonoscopy. After 18 years of follow-up, the cumulative incidence of colorectal cancer was significantly lower in the annual and biennial screening groups (32 and 33 cases per 1000, respectively) than in the control group (39 per 1000).

Comment: FOBT remains the only screening test proven in randomized trials to decrease colorectal cancer mortality, and it appears to reduce incidence, too. Still, debate will continue about which screening test is best (JW Aug 15 2000, p. 125, accession number 000804001, and N Engl J Med 2000;343:162, 169). An editorialist points out that we should expect differing views on whether the small incremental harm of an invasive test like colonoscopy is worth the similarly small increment in benefit. Because most Americans have never been screened, rigid recommendations may not be optimal. He suggests that the best test may be whichever one the patient wants.

— R Saitz

Published in Journal Watch General Medicine December 15, 2000

Citation(s):

Mandel JS et al. The effect of fecal occult blood screening on the incidence of colorectal cancer. N Engl J Med 2000 Nov 30 343 1603-1607.

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Woolf SH. The best screening test for colorectal cancer -- A personal choice. N Engl J Med 2000 Nov 30 343 1641-1643.

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