BMJ  2003;327:E196-E197 (4 October), doi:10.1136/bmjusa.03030002 (published 12 April 2003)

BMJ USA: Editorial

New colorectal cancer screening guidelines

A consensus for action

From BMJ USA 2003;Mar:126

Colorectal cancer is an important health issue in the United States. Every year it accounts for approximately 130 000 new cases and 55 000 deaths among both men and women, costs more than $6 billion, and claims approximately 165 000 life-years.¹ Guidelines published years ago suggested that screening could reduce this toll by detecting early-stage curable cancer. We had known for four decades that colorectal cancer evolved slowly from premalignant polyps, providing a long window of opportunity to detect cancer early, and possibly, to remove polyps and thereby prevent cancer altogether.¹

It was not until new technological advances in the early 1970s that screening became feasible, however. These developments included guaiac cards with a stable reagent, flexible sigmoidoscopy, and colonoscopy. This gave clinicians the total package of screening tests and a means of accurate diagnostic work-up and effective treatment with polypectomy and curative surgery. Screening was challenged for years because of concerns over screening bias, overdiagnosis, and harms. However, the largest criticism—that screening was not proven to reduce mortality from colorectal cancer—was laid to rest in the 1990s with the publication of well-designed prospective randomized trials and case-control studies. Further support now comes from early outcome data from screening colonoscopy studies. These trials have demonstrated not only mortality benefits but also that screening is cost-effective and that removal of polyps prevents cancer.^1-4

The latest guidelines on colorectal cancer screening were issued in February 2003 by the US Multisociety Task Force on Colorectal Cancer.² This American Gastroenterological Association–sponsored task force included gastroenterologists, surgeons, endoscopists, radiologists, family physicians, internists, and oncologists. The guidelines, which updated recommendations issued in 1997, add to a list of guidelines published since 1996 that have systematically examined the evidence and concluded that colorectal cancer screening is effective. Similar recommendations in favor of screening have been issued by the American Academy of Family Physicians, the American Cancer Society, the American College of Gastroenterology, the American College of Obstetricians and Gynecologists, the American College of Surgeons, the US Preventive Services Task Force, the European Cancer Screening Group, the World Health Organization, the Ontario Expert Panel, and the Australian Health Technology Advisory Committee.^{1 3 5 7}

There is now a consensus that all men and women age 50 and older should be offered screening for colorectal cancer and adenomatous polyps. Screening should be offered to younger patients if there are familial factors that increase their risk. The new guidelines examined recent evidence, which provides the basis for modified recommendations regarding specific screening tests, diagnostic work-up, and follow-up surveillance. The options for screening include annual fecal occult blood testing (FOBT), flexible sigmoidoscopy every five years (or the two combined), colonoscopy every 10 years, or barium enema every five years. Guaiac-based stool blood tests with a range of sensitivity and newer highly sensitive and specific immunochemical tests are available for clinical use.^{8 9}

A major change from prior recommendations is that of colonoscopy for the screening of persons whose close relatives developed colorectal cancer or adenomas before age 60, for diagnostic evaluation, and for surveillance after polypectomy or cancer surgery. Screening and diagnosis can be offered either with screening colonoscopy every 10 years or with a two-stage approach involving FOBT and/or flexible sigmoidoscopy followed by diagnostic colonoscopy in persons whose screening test is positive. The role of barium enema has diminished; for screening, it is now recommended every five years rather than every 10 years because of its low sensitivity.

Another major change in recommendations is that patients who have undergone polypectomy require less intensive follow-up surveillance (every five years instead of every three years) if they are at low risk for future advanced adenoma (1 cm, with villous components, high-grade dysplasia or malignant polyp).¹ These low-risk patients can be identified by characteristics at the time of polypectomy (one or two tubular adenomas <1 cm in size). When colonoscopic polypectomy was first introduced, patients were asked to return annually for follow-up surveillance. Evidence from the National Polyp Study subsequently demonstrated that a three-year interval was safe.¹⁰ Newer evidence now indicates that five years is appropriate for about two thirds of patients who have undergone polypectomy.

National adherence to these surveillance recommendations would free up resources to make colonoscopy more available for screening and diagnostic purposes. Although colonoscopy was first introduced as a diagnostic test for symptomatic patients, it has since evolved into "one-stop shopping" (diagnosis and treatment) for patients with positive screening tests, and more recently, for screening itself.¹¹ Controversy persists as to whether the incremental benefits offered by colonoscopy screening offset its potential harms.

A third major change in the new guidelines is that genetic counseling is recommended wherever genetic testing is considered. Primary care clinicians should consider the implications for their practice.

Guidelines are only a starting point. Physicians need to incorporate them into their overall approach to health maintenance, along with promoting a healthy lifestyle and screening for other diseases. Although colorectal cancer is highly prevalent and preventable, most Americans are not being screened. Many state that their doctor has not recommended screening. Colorectal cancer screening is now considered the standard of care for persons age 50 and older, and its omission is a frequent source of litigation. The new guidelines urge patients not to procrastinate while waiting for emerging technologies such as virtual colonoscopy or stool DNA mutation testing. These tools are promising but remain experimental.⁹ The message to patients should be to get screened now. Any screening test is better than none and can be life-saving.

Memorial Sloan-Kettering Cancer Center, New York City winawers{at}mskcc.org

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Competing interests: Medical Advisory Board, Exact Sciences and Enterix.

References

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3. Winawer SJ, Fletcher RH, Miller L, et al. Colorectal cancer screening: clinical guidelines and rationale. Gastroenterology 1997;112:594-642.[CrossRef][ISI][Medline]
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8. Young GP, St John JB, Winawer SJ, Rozen P. Choice of fecal occult blood tests for colorectal cancer screening: recommendations based on performance characteristics in population studies: a WHO (World Health Organization) and OMED (World Organization for Digestive Endoscopy) report. Am J Gastroenterol 2002;97:2499-2507.[ISI][Medline]
9. Levin B, Brooks D, Smith R, Stone A. Emerging technologies in screening for colorectal cancer: CT colonography, immunochemical fecal occult blood tests, and stool screening using molecular markers. CA Cancer J Clin 2003;53:44-55.[Abstract/Free Full Text]
10. Winawer SJ, Zauber AG, O'Brien MJ, et al. Randomized comparison of surveillance intervals after colonoscopic removal of newly diagnosed adenomatous polyps. N Engl J Med 1993;328:901-906.[Abstract/Free Full Text]
11. Lieberman DA, Weiss DG, Bond JH, et al. Use of colonoscopy to screen asymptomatic adults for colorectal cancer. N Engl J Med 2000;343:162-174. [Abstract/Free Full Text]

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Population screening for colorectal cancer

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