CT colonography may yet challenge colonoscopy

NEW YORK (Reuters Health) - Although CT colonography (CTC) is a promising technique that has good sensitivity for detecting larger colon polyps and is less invasive than colonoscopy, it does not appear to be cost effective for average-risk colorectal cancer screening. However, used in the right circumstances, the CT technique could prove to be economically viable, according to US and Dutch researchers.

They estimated the threshold costs for which CTC would be an economical alternative to colonoscopy for colorectal cancer screening. The results "support the effectiveness of CTC for colorectal cancer screening," investigator Dr. Ann Graham Zauber told Reuters Health, "but also show that to be cost effective as well, the CTC costs could not be more than 43% of that for optical colonoscopy," for similar levels of adherence.

In the March issue of the International Journal of Cancer, Dr. Zauber of Memorial Sloan-Kettering Cancer Center, New York, and colleagues note that the costs of CTC have not been well established. To help do so, they estimated costs and life years gained in patients aged 50 to 80 years and compared these with the results of colonoscopy under various strategies.

The model employed looked at screening intervals of 5, 10, 15 and 20 years. The researchers calculated that for the CTC approach to do as well as optical colonoscopy every 10 years, it should be offered every 5 years and suspected polyps of 6 mm or more should be referred for colonoscopy.

To be cost effective in this setting, they estimate that costs should not be greater than 43% of those of colonoscopy.

However, if adherence to CTC were 25% greater than that with colonoscopy, perhaps because of the possible absence of cathartic preparation, then the threshold cost could rise to 71% of the optical technique and still be cost effective.

Because of this potential development and because CTC reading appears less time consuming, the researchers conclude that achieving such cost levels appears to be possible.

Copyright © 2009 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.