(ChemotherapyAdvisor) – Conducting narrow band imaging (NBI) enables endoscopists to accurately predict histology of polyps without resection, according to a team of researchers of the Indiana University School of Medicine, Indianapolis, IN. This conclusion is based on a study entitled “Leaving distal colorectal hyperplastic polyps in place can be achieved with high accuracy by using narrow-band imaging: an observational study,” which was published in the August issue of Gastrointestinal Endoscopy.

In this study, the investigators aimed to “assess the accuracy of predicting histology by using NBI in real time for distal colorectal polyps.” To meet their aim, a prospective observational study was conducted to evaluate histology in 225 adults undergoing elective screening or surveillance colonoscopy.

The investigators used high-definition colonoscopy and NBI without optical magnification to detect colorectal polyps and adenomomas. In total, 235 distal (rectosigmoid) colorectal polyps from 31 patients were subjected to histologic examination.

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“Before resection, histology was predicted, and a level of confidence (high or low) was assigned,” the investigators wrote.

NBI turned out to be a predictive model of colorectal histology, with an accuracy of 97.7%, sensitivity for adenomatous histology of 93.9%, specificity of 98.4%, negative predictive value of 97.9%, and positive predictive value of 75.6%.

“The performance characteristics for predicting diminutive distal polyps (≤ 5mm) with high confidence were sensitivity 96.0%, specificity 99.4%, negative predictive value 99.4%, and positive predictive value 96.0%,” the investigators reported.

Based on these findings, the investigators concluded, “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.”