Diagnostic performance of Japan NBI Expert Team (JNET) classification and CONECCT classification for large colorectal laterally spreading lesions treated by endoscopic submucosal dissection: a large western cohort study

Aims Endoscopic characterization aims to predict histology of a lesion and thus the risk of cancer. The JNET (Japan NBI Expert Team) classification is the classification proposed by guidelines to select the optimal therapeutic approach between EMR (endoscopic mucosal resection), ESD (endoscopic submucosal dissection), or surgery but has not been evaluated in large laterally spreading lesions. CONNECT classification adds macroscopic features to the JNET classification.

Methods Single-center prospective observational study. All patients referred for endoscopic resection of lesions larger than 20 mm.

Results 972 lesions removed by en-bloc ESD were included from 2017 to 2022. 110 (11,3%) of these lesions contained submucosal invasive carcinoma (SMIC). The sensitivity and specificity for predicting high-grade dysplasia (HGD) to SMIC were 46% and 75% for JNET 2B and 87% and 38% for CONECCT IIC, respectively; and for predicting superficial SMIC were 67% and 67% for JNET 2B and 94% and 27% for CONECCT IIC, respectively. No association was found between covert carcinoma (submucosal carcinoma without demarcated abnormalities during optical diagnosis, corresponding to the JNET 2A classification) and buried carcinoma (presence of SMICs, more than 0.5 mm from the surface, where only non-tumoral cells are identified (low-grade dysplasia (LGD) or HGD)).

Conclusions The JNET classification has a low diagnostic accuracy for predicting submucosal cancer risk in large laterally spreading lesions. The CONECCT classification has a high sensitivity for predicting SMIC. When a selective ESD and piecemeal-EMR strategy is used according to submucosal cancer risk, the CONECCT classification should be preferred to avoid undertreatment of SMIC.

Conflicts of interest

Authors do not have any conflict of interest to disclose.

Publication History

Article published online:
15 April 2024