Mo1635 CLASSIFICATION OF NUCLEAR MORPHOLOGY OF EC FINDINGS IN COLORECTAL ENDOCYTOSCOPY

Abstract

Endocytoscopy (EC) is a next-generation endoscopy that allows diagnostic imaging at 520× magnification. In the EC classifications, lesions diagnosed as EC3a vary extensively from adenoma to carcinomas with massive submucosal invasion (SM-m), including some lesions that are unsuitable for endoscopic treatment. Therefore, to improve the accuracy of assessing the depth of invasion based on the EC classification, we investigated the presence or absence of 2 factors; high degree of nuclear enlargement (HNE) and multilayered nuclei (MNs), that are indicators of SM-m. Between May 2005 and August 2018, we retrospectively examined 866 lesions diagnosed as EC2 or EC3, according to the EC classification. We subclassified EC 3a into 2 grades (low or high grade) and defined low grade as not recognizing both HNE and MNs, and high grade as for any of the two factors. We examined the diagnostic accuracy of SM-m based on this EC3a subclassification. In addition, we compared the diagnostic ability of EC for SM-m with that of other modalities; narrow-band imaging (NBI) and pit pattern. The sensitivity, specificity, positive predictive value (PPV), negative predictive value NPV), accuracy, and positive likelihood ratio for the diagnostic accuracy of the EC3a subclassification were 89.3%, 91.2%, 80.6%, 92.3%, 90.6%, and 10.1, respectively (P < 0.001). Diagnostic performance for predicting SM-m or worse among EC, NBI and pit pattern is as follows: The sensitivity, specificity, PPV, NPV, and accuracy about EC were 95.1%, 96.5%, 94.9%, 96.7%, 96.0% respectively. On the other hand, those of NBI were 65.0%, 98.7%, 97.0%, 80.7%, 85.1%, and pit pattern were 88.8%, 96.0%, 93.7%, 92.7%, 93.1%, respectively. The sensitivity, specificity, NPV, and accuracy of EC were significantly higher than those of NBI .(P < 0.05) . Futhermore, the sensitivity, NPV, and accuracy of EC were significantly higher than those of pit pattern. (P < 0.05) From the EC findings, the presence of HNE, and MNs are important risk factors for SM-m or worse outcomes. Furthermore, the EC3a subclassification taking account of these findings could be effective for the diagnosis of SM-m or worse.