Diagnostic performance of endocytoscopy with normal pit‐like structure sign for colorectal low‐grade adenoma compared with conventional modalities

OBJECTIVES: A “resect‐and‐discard” strategy has been proposed for diminutive adenomas in the colorectum. However, this strategy is sometimes difficult to implement because of the lack of confidence in differentiating low‐grade adenoma (LGA) from advanced lesions such as high‐grade adenoma or carcinoma. To perform real‐time precise diagnosis of LGA with high confidence, we assessed whether endocytoscopy (EC) diagnosis, considering normal pit‐like structure (NP‐sign), an excellent indicator of LGA, could have additional diagnostic potential compared with conventional modalities. METHODS: All the neoplastic lesions that were observed by non‐magnifying narrow‐band imaging (NBI), magnifying NBI (M‐NBI), magnifying pit pattern, and EC prior to pathological examination between 2005 and 2018 were retrospectively investigated. The neoplastic lesions were classified into two categories: LGA and other neoplastic lesions. We assessed the differential diagnostic ability of EC with NP‐sign between LGA and other neoplastic lesions compared with that of NBI, M‐NBI, pit pattern, and conventional EC in terms of sensitivity, specificity, accuracy, and area under the receiver operating characteristic curve (AUC). RESULTS: A total of 1376 lesions from 1097 patients were eligible. The specificity (94.9%), accuracy (91.5%), and area under the receiver operating characteristic curve (0.95) of EC with NP‐sign were significantly higher than those of NBI, M‐NBI, pit pattern, and conventional EC. CONCLUSIONS: EC diagnosis with NP‐sign has significantly higher diagnostic performance for predicting colorectal LGA compared with the conventional modalities and enables stratification of neoplastic lesions for “resect‐and‐discard” with higher confidence.