Chromoendoscopy with indigo carmine in flexible sigmoidoscopy screening: does it improve the detection of adenomas in the distal colon and rectum?

BACKGROUND AND AIMS The aim of our study was to determine whether chromoendoscopy with indigo carmine significantly improves the detection of adenomas in the distal colon and rectum and therefore could become routine in flexible sigmoidoscopy screening. METHODS Between 2001- 2003, two sigmoidoscopies, the first conventional, the second with chromoendoscopy, were performed in a "back-to-back" design by two experienced endoscopists in a series of 55 patients. All lesions were classified with regard to position and size before and after staining, then endoscopically removed and referred to two experienced pathologists. RESULTS 55 patients, mean age 60 +/- 9.8 (42-79) years, 34 (61.8%) men and 21 (38.2%) women were enrolled. After staining, 47 patients had 373 visible lesions, 306 (82%) < 3mm, 47 (12.6%) 3- 5 mm and 20 (5.4%) > 5 mm. Histologically, 215 (57.7%) were hyperplastic polyps, 27 (7.2%) adenomas and 131 (35.1%) other lesions. With chromoendoscopy, in 17 of the 47 patients (36.2%) 27 adenomas (15 5 mm) were detected. Chromoendoscopy significantly improved the detection of adenomas <or= 5 mm (p<0.01). Regarding the detection of adenomas larger than 5 mm, there was no significant difference between conventional sigmoidoscopy and chromoendoscopy. The chi-square test was performed for comparisons between the number of lesions detected by standard sigmoidoscopy and chromoendoscopy. CONCLUSIONS Chromoendoscopy with indigo carmine allows the detection of significantly more adenomas <or= 5 mm in the distal colon and rectum. Thus, flexible sigmoidoscopy with routine chromoendoscopy could become an option in colorectal cancer screening when colonoscopy is unavailable or not accepted by the patient.