Polypectomy (the surgical removal of polyps by colonoscopy) of small polyps found during CT colonography is costly and unnecessary according to a study performed at the University of Wisconsin School of Medicine and Public Health in Madison, WI.
A decision analysis model was constructed to represent the clinical and economic consequences of performing three year colorectal cancer surveillance, immediate colonoscopy with polypectomy, or neither on patients who have 6-9 mm polyps found on CT colonography (CTC). The analysis model was accompanied by a hypothetical population of 100,000 60-year-old adults with 6- to 9-mm polyps detected at CTC screening.
Results showed that, “by excluding large polyps and masses, CTC screening can place a patient in a very low risk category making colonoscopy for small polyps probably not warranted,” said Perry J. Pickhardt, MD, lead author of the study. “Approximately 10,000 colonoscopy referrals would be needed for each theoretical cancer death prevented at a cost of nearly $400,000 per life-year gained. We would also expect an additional 10 perforations and probably one death related to these extra colonoscopies. There may be no net gain in terms of lives—just extra costs,” said Dr. Pickhardt.
“The clinical management of small polyps detected at colorectal cancer screening has provoked controversy between radiologists and gastroenterologists. Patients should be allowed to have the choice between immediate colonoscopy and imaging surveillance for one or two isolated small polyps detected at colorectal cancer screening,” said Dr. Pickhardt.
CT colonography is now a recommended test for colorectal cancer screening by the American Cancer Society. “If patients with small polyps are monitored, only five percent of adults undergoing CTC screening will need to undergo immediate invasive colonoscopy,” said Dr. Pickhardt.
This study appears in the November issue of the American Journal of Roentgenology.
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