A new guideline adds noninvasive options but with many caveats.
The American Cancer Society, the American College of Radiology, and the Multi-Society Task Force on Colorectal Cancer (comprising several gastroenterology groups) have issued a new guideline for colorectal cancer screening in average-risk adults. The guideline is based on eight published guidelines, supplemented by articles published in the past 5 years, unpublished articles and abstracts provided by expert panel members, and expert opinion.
Recommendations include providing one of the following:
Guaiac-based fecal occult blood testing (FOBT) annually
Fecal immunochemical testing annually
Flexible sigmoidoscopy every 5 years
Double-contrast barium enema every 5 years
Computed tomographic colonography every 5 years
Colonoscopy every 10 years
Stool DNA testing (interval uncertain)
The guidelines encourage testing that can detect adenomatous polyps as well as cancer (i.e., the 4 radiological and endoscopic options listed above). Stool DNA testing is recommended primarily based on data that suggest that the test is sensitive and not less specific than FOBT. Similarly, computed tomography is recommended because its sensitivity and specificity are comparable to those of traditional colonoscopy. But the guidelines also note substantial shortcomings of these two tests. Currently available DNA tests have not been evaluated in screening cohorts, costs are higher than for other stool tests, and optimal test frequency is unknown. Limitations associated with computed tomography include radiation exposure, general lack of third-party payment for screening, and operator-dependent results with quality assurance efforts as yet undeveloped.
Comment: This guideline is freely available on the American Cancer Society website and adds several new screening options. But rather than adding new screening options for those at average risk, most clinicians likely will continue to follow their current practice, largely because of limited evidence for some procedures and the shortcomings described in this report. In 2002, the U.S. Preventive Services Task Force updated its colorectal cancer screening guidelines, based on a systematic review of controlled trials that examined the effect of screening tests on health outcomes (Journal Watch Aug 13 2002). They primarily recommended FOBT, sigmoidoscopy, or colonoscopy. From a population and clinical-practice perspective, at least, no alternative tests yet offer better balances of benefits, harms, and costs.
— Richard Saitz, MD, MPH, FACP, FASAM
Published in Journal Watch General Medicine March 27, 2008
Citation(s):
Levin B et al. Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: A joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology. CA Cancer J Clin 2008 Mar 5; [E-pub ahead of print]. (http://dx.doi.org/10.3322/CA.2007.0018)