Controversy Brews Over Best Strategy for Colon Cancer Screening

Laurie Barclay, MD

June 14, 2012

In This Article

June 14, 2012 — Controversy is still brewing over optimal strategies for colorectal cancer screening, according to a letter to the editor in the New England Journal of Medicine regarding an editorial, and the editorialists' response, both published in the May 31 issue.

Worldwide, colorectal cancer is the third most common cancer, with a lifetime risk of approximately 5% in the United States. Colonoscopy and fecal immunochemical testing (FIT) are both accepted strategies for colorectal cancer screening in the average-risk population, but issues regarding these tests include sensitivity and specificity for detecting adenomas and cancers, compliance with screening, and cost.

"Further research with FIT and new blood and fecal DNA tests is being done, and more data on sensitivity for advanced adenomas, cancer, and acceptance of testing over multiple rounds will be forthcoming," James E. Allison, MD, clinical professor of medicine emeritus at the University of California San Francisco and San Francisco General Hospital in the Division of Gastroenterology, and adjunct investigator in the Kaiser Division of Research, told Medscape Medical News in an email.

"The FIT data are already very compelling and led to a recent change in the American Cancer Society's recommendation for using [this test]," Dr. Allison said. "The idea that only structural exams find advanced adenomas is being put to rest in the United States, as is evident from recent statements from the National Cancer Institute and the American College of Physicians."

As previously reported by Medscape Medical News, 2 studies published February 23 in the New England Journal of Medicine addressed some of the issues regarding colorectal cancer screening.

The first study was a retrospective analysis from the National Polyp Study (NPS) by Ann G. Zauber, PhD, and colleagues, showing that colonoscopic removal of adenomatous polyps was associated with a 53% reduction in colorectal cancer mortality during a mean follow-up of 15.8 years.

The second study was a large, randomized controlled trial by Enrique Quintero, MD, PhD, and colleagues from the COLONPREV Study, showing that real-world screening rates remain low. Among participants aged 50 to 69 years, only 24.6% accepted once-only screening with colonoscopy. About one third (34.2%) agreed to the first of 5 biennial screenings with FIT, and the investigators and editorialists anticipated that compliance with FIT would decrease over time.

Although colonoscopy and FIT were equally effective for detecting colorectal cancer, colonoscopy had significantly better diagnostic yield for adenomas, which are a strong predictor of cancer risk. Advanced adenomas were detected in 1.9% of the colonoscopy group and in 0.9% of the FIT group (odds ratio, 2.30; P < .001). Nonadvanced adenomas were detected in 4.2% of the colonoscopy group and in 0.4% of the FIT group (P < .001).

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