Accuracy for optical diagnosis of colorectal polyps in clinical practice

Optical diagnostic involves predicting polyp histopathology from its endoscopic characteristics. It is only recommended for diminutive polyps ( < or = 5 mm) and for predictions made with high confidence.

To evaluate the accuracy of optical imaging in clinical practice and to assess if optical diagnosis is useful for predicting future colonoscopy surveillance intervals without waiting for histopathological analysis.

consecutive > 18 years patients were enrolled in this prospective study. Colonoscopies were performed by five expert endoscopists who previously participated in an ex-vivo training. Colonoscopes CF-H180AL and CF-Q180AL were used together with Exera II (Olympus Medical System, Tokyo, Japan) processors. Each polyp was characterized in real time using white light and Narrow Band Imaging. Accuracy of optical diagnosis (S, E, NPV, PPV) and correlation between surveillance interval based on optical diagnosis and histopathological analysis were calculated.

311 colon polyps < 10 mm (216 diminutive) in 195 patients were analyzed. Accuracy of optical diagnostics for predictions made with high confidence: Diminutive polyps(sensitivity 0.59, specificity 0.92, NPV 0.48); polyps < 10 mm (sensitivity 0.73, specificity 0.88, NPV 0.50). An optical diagnosis based surveillance recommendation was given to 90 patients. Concordance with histopathology based recommendation was 92.2% according to the European guideline and 93.3% according to the ESGE guideline.

Optical diagnostics can be used to predict future surveillance intervals immediately after colonoscopy. However, in this study, based on clinical practice, the accuracy of optical imaging is below the recommended standards.