Background: Accurate colonoscopic assessment of colorectal polyp histology could avoid resection of distal nonadenomatous polyps and reduce costs and risk. Objective: To assess the accuracy of predicting histology by using narrow-band imaging (NBI) in real time for distal colorectal polyps. Design: Prospective observational study. Setting: University hospital and ambulatory surgery center. Patients: This study involved 225 consecutive adults undergoing elective screening or surveillance colonoscopy. Intervention: We evaluated real-time histology of 235 distal (rectosigmoid) colorectal polyps from 31 patients by using high-definition colonoscopy and NBI without optical magnification. For each polyp, the endoscopist described size, Paris classification, and surface characteristics (vascular and pit pattern, color, pseudodepression). Before resection, histology was predicted, and a level of confidence (high or low) was assigned. Main Outcome Measurements: Sensitivity and negative predictive value of high-confidence endoscopic predictions of adenomatous versus hyperplastic histology for polyps ≤5 mm. Results: The accuracy of a high-confidence endoscopic prediction was 97.7%, sensitivity for adenomatous histology 93.9%, specificity 98.4%, negative predictive value 97.9%, and positive predictive value 75.6%. The performance characteristics for predicting diminutive distal polyps (≤5 mm) with high confidence were sensitivity 96.0%, specificity 99.4%, negative predictive value 99.4%, and positive predictive value 96.0%. Limitations: Single-center study with a single endoscopist. Conclusion: NBI without optical magnification is sufficiently accurate to allow distal hyperplastic polyps to be left in place without resection and small, distal adenomas to be discarded without pathologic assessment. These findings validate NBI criteria based on color, vessels, and pit characteristics for predicting real-time colorectal polyp histology.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging