Removing small colon polyps costly, unnecessary

By Will Boggs, MD

NEW YORK (Reuters Health) - The surgical removal of small colon polyps found during computed tomography imaging of the colon, or CT colonography, is costly and unnecessary, according to a new study.

"We shouldn't aggressively pursue sub-centimeter lesions, since the costs, risks, and inconvenience of the subsequent colonoscopy outweighs the clinical importance of these small polyps," Dr. Perry J. Pickhardt from University of Wisconsin School of Medicine and Public Health in Madison told Reuters Health. "Over time, the few small polyps that matter will declare themselves by showing interval growth," the researcher added.

Colonoscopy is a colorectal cancer screening test performed with a small camera and under sedation that allows doctors to detect precancerous growths in the colon and remove them on the spot.

Pickhardt and colleagues calculated the relative benefits, harms and costs of CT surveillance versus immediate colonoscopy with polyp removal in a hypothetical population of 100,000 60-year-olds with small growths measuring 6 to 9 millimeters that were found on CT colonography.

By excluding large polyps and masses, CT screening can place a patient in a very low risk category making removal of small polyps probably not warranted, Pickhardt noted in a written statement.

"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," the researcher explained. "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 Pickhardt.

How best to manage small polyps detected at colorectal cancer screening has provoked controversy between radiologists and gastroenterologists, Pickhardt noted. "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 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," Pickhardt noted.

SOURCE: American Journal of Radiology, November 2008.