Abstract
INTRODUCTION: Sessile serrated adenoma/polyp (SSA/P) is an early precursor lesion in the serrated neoplasia pathway, which results in BRAF-mutated colorectal carcinomas with high levels of microsatellite instability. Therefore, accurate diagnosis of SSA/P and its dysplastic components is endoscopically important. However, the usefulness of magnifying narrow-band imaging (NBI) endoscopy for SSA/Ps with dysplastic change has not yet been fully elucidated. The aim of this study was to verify the usefulness of magnifying NBI endoscopy for the diagnosis of SSA/P with dysplasia/carcinoma. METHODS: Among 939 endoscopically or surgically resected lesions pathologically diagnosed as SSA/P with or without dysplasia/carcinoma at Juntendo University Hospital (Tokyo, Japan) between 2011 and 2018, a total of 709 lesions had images available. These SSA/P lesions included 647 with no dysplasia (ND), 37 with low-grade dysplasia (LGD), 15 with high-grade dysplasia (HGD), and 10 with submucosal invasive carcinoma (SIC). We retrospectively evaluated magnifying NBI endoscopic findings using the Japan NBI Expert Team (JNET) system. RESULTS: The clinicopathological and endoscopic characteristics of the studied lesions are summarized in Table 1. The HGD and SIC lesions were associated with advanced age. All the lesions were more frequently located in the proximal colon. The SIC lesions were significantly larger than the ND and LGD lesions. All the lesions frequently exhibited endoscopic findings characteristic of SSA/P, such as mucus cap and Type II-Open pit pattern. As for the JNET classification of magnifying NBI endoscopy findings, all 709 lesions were type 1. Six hundred and eighteen (96%) ND lesions exhibited type 1 only, whereas 52 (84%) SSA/P with dysplasia/carcinoma lesions had a combination of type 1 and types 2A, 2B, or 3, corresponding to SSA/P and dysplasia/carcinoma, respectively (Figures 1 and 2). Furthermore, the JNET classification had high sensitivity (84%) and specificity (96%) for diagnosing SSA/P with dysplasia/carcinoma. CONCLUSION: Recently, the JNET was established and has proposed a universal NBI magnifying endoscopic classification of colorectal tumors. Our findings suggest that the use of magnifying NBI endoscopy using the JNET classification might be useful for the diagnosis of not only conventional colorectal tumors, but also SSA/P with dysplasia/carcinoma. This increased awareness may also improve the recognition of SSA/Ps with dysplasia or invasive carcinoma.
Published Version
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