[Role of chromoendoscopy in colorectal polyps handling]

Endoscopic polipectomy and its further histopathologic study are current gold standard in diagnosis of colorectal polyps is. It was proposed that colonoscopy with high resolution videoendoscopes with or without magnification combined with indigo carmin dye (ICD) could distinguish between adenomatous and nonadenomatous polyps according to their pit pattern. The aim of this study was to establish sensitivity and specificity of chromoendoscopy with ICD using conventional videoendoscopes and fiber-endoscopes with videocamera, to make a differential diagnosis of polyp histology and their possible role in colon cancer screening.

Step 1: Using previous trial data, the first 20 polyps < = 1 cm was retrospectively correlated with their known histology to determine the pit pattern of each histologic type; this data was used in the step 2 patients. Step 2: 46 patients with colorectal polyps were enrolled in this prospective study. Polyps were sprayed with 0.4% ICD, after that the polyps were sorted into adenomatous or non, they were all removed and submitted for histophatologic evaluation.

The chi square method was used.

19 patients were evaluated with videoendoscopes (group 1) and 27 with fiberendoscopes (group 2); in seven cases the pattern of the polyps could not be identified and the patients were excluded. Group 1: coincidence prediction/histology 94.7% (p < 0.0001), sensitivity 100% and especificity 88%. Group 2: coincidence prediction/histology 65.8% (p < 0.05), sensitivity 86% and especificity 60%.

Adenomatous and non-adenomatous polyps can be distinguished by chromoendoscopy with high sensitivity and specificity. However, because fiberendoscopy could ot be identify pit pattern in 15.2% and has a low negative predictive value we do not recommend to use it. Nevertheless, the results obtained with ideo-endoscopes involve potential usefulness in colon cancer screening and possible decrease in their risks and costs.