Researchers from the USA determined the accuracy of high-resolution chromoendoscopy for the determination of colonic polyp histology.
A total of 299 patients referred for routine colonoscopy or sigmoidoscopy were included in the multicenter trial. In these, 520 polyps of 10 mm in size were sprayed with indigo carmine dye.
Using a high-resolution endoscope, the endoscopist predicted the histology of each polyp based on its surface characteristics.
Hyperplastic polyps had a "pitted" surface pattern of orderly-arranged "dots" that resembled surrounding normal mucosa.
Adenomatous polyps had at least one surface "groove" or "sulcus".
Each polyp was subsequently resected for histopathologic evaluation.
|Chromoendoscopy for detecting adenomatous polyps:|
Negative predictive value: 88%
| Gastrointesinal Endoscopy |
The resected polyps were comprised by 193 adenomas (37%), 225 hyperplastic polyps (43%), and 102 "other" types (20%).
Some 40 polyps (8%) could not be classified by high-resolution chromoendoscopy with indigo carmine dye.
For the remaining polyps, the sensitivity, specificity, and negative predictive value of indigo carmine dye staining for adenomatous polyps were, respectively, 82%, 82%, and 88%.
The team found that the results were consistent among the academic centers and the primary care practice involved in the study.
Dr Glenn M. Eisen concluded on behalf of his group, "High-resolution chromoendoscopy with indigo carmine dye demonstrates morphologic detail of diminutive colorectal polyps that can reliably be used to separate adenomatous from nonadenomatous polyps."