Headlines
As reported by GI & Hepatology News, October 2010.
Small Adenomas: A Big Problem
The increasing detection rate of diminutive polyps is changing how endoscopists view these small lesions in the course of colon cancer screening. Studies using commercially available high-definition colonoscopes (Gastrointest. Endosc. 2010;71:1234-40; Am. J. Gastroenterol. 2010;105:1301-7) have yielded adenoma detection rates in screening populations that are much higher than in previously published studies (Am. J. Gastroenterol. 2003;98:2777- 83; N. Engl. J. Med. 2000;343:169-74).
Resection of these polyps can be associated with complications and substantial pathology cost. Therefore, the benefit from removal is small, given their low risk of malignancy.
In response to these problems, some experts have recommended a “resect and discard” policy (Clin. Gastroenterol. Hepatol., see page 9 of this issue) designed to decrease cost while maintaining the efficacy of cancer prevention with colonoscopy. While this recommendation appears to address the concern of cost, there are some issues which require further examination.
The first question is how to identify the histology of these polyps prior to discarding them. "Real time" histology would likely be performed by the endoscopist and may possibly require the aid of new technology in determining the pathology of the polyp. One study has shown that only 20 minutes are required to use narrow-band imaging to differentiate adenomas from other polyps (Gastrointest. Endosc. June 17, 2010, epub ahead of print). Thus, endoscopists may soon adopt a new role in colorectal cancer screening which will likely require some training in identifying pathology.
Another issue is how to deal with multiple polyps. Specifically, while it is recognized and accepted that small adenomas pose a small risk with regard to malignant potential as well as metachronous lesions (Gastroenterology 2007;133: 1077-85), multiple adenomatous lesions have been shown to be predictive of future adenomas (Gastroenterology 1998;115:13-8; N. Engl. J. Med. 1993;328:901-6).
Although discarding one or two small polyps will likely not change the surveillance of the patient, detection of more than two adenomas may change the interval of surveillance by several years. Thus, histologic confirmation by a pathologist may be needed for patients with multiple detected polyps. Finally, with an increasing detection rate for these small adenomas, we may want to consider raising the threshold for intense surveillance from three adenomas to a higher number. Thus, more studies are required.
Joseph C. Anderson, M.D., is Associate Professor of Medicine, University of Connecticut Health Center, Farmington. He has no relevant disclosures.