For Release:
June 14, 2000, 5 PM EDT
Contact: Michael Bernstein
(703) 648-8910 [email protected]
ACR Seriously Questions Colon Cancer Study Conclusions
The American College of Radiology (ACR) today said a study published in the June 15 New England Journal of Medicine grossly underestimates the value of double-contrast barium enema (DCBE) as a tool for preventing colon cancer.
"We question the validity of the numbers cited in the study and the manner in which the size of the polyps assessed by DCBE was calculated," said Seth N. Glick, MD, chair of the ACR Colon Cancer Committee. "DCBE has a superior sensitivity for those polyps that are larger and, therefore, a more significant threat. That sensitivity is understated in the study."
"The study only evaluated 23 'larger' lesions (greater than 1 centimeter), with almost all measuring exactly 10 millimeters in diameter. Other studies have shown that the method they used to calculate polyp size often is inaccurate and leads to estimates that are several millimeters too high," he contended.
Dr. Glick said it is probable that most, if not all, polyps listed in the largest size category were miscalculated and, therefore, included inappropriately. He maintained that, " This is supported by the fact that in the same study DCBE had a similar performance for polyps 5 mm to 10 mm. This is in contrast to the established literature, which shows that DCBE sensitivity improves markedly with increasing polyp size."
He added that "colonoscopy, as shown in the study, is superior for smaller polyps, but are we benefiting the public by removing all of these tiny polyps, using a test that is 25 times more risky and 5-6 times more expensive than DCBE, when the vast majority will not cause patients any problems? The tiny polyps are common and the larger, more dangerous ones, are relatively rare."
Dr. Glick said ACR is not criticizing colonoscopy, which can be a very effective test. "We simply are saying that it is not the only effective test. DCBE is clearly an acceptable alternative for finding larger more dangerous, polyps."
Exposing the vast majority to a more expensive, invasive test may not be justified by the differences in polyp detection rate when the ultimate goal is to efficiently and safely reduce the mortality from colorectal cancer, Dr. Glick contended.
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