NBI magnifying endoscopic classification of colorectal tumors proposed by the Japan NBI expert team (JNET)

Yutaka Saito, Takahisa Matsuda, Takeshi Nakajima, Taku Sakamoto, Masayoshi Yamada, Shoichi Saito, Hiroaki Ikematsu, Yoshiki Wada, Shiro Oka, Hiroshi Kawano, Yasushi Sano, Shinji Tanaka, Takahiro Fujii, Shin Ei Kudo, Toshio Uraoka, Nozomu Kobayashi, Hisashi Nakamura, Kinichi Hotta, Takahiro Horimatsu, Naoto SakamotoKuang I. Fu, Osamu Tsuruta, Hiroshi Kashida, Yoji Takeuchi, Hirohisa Machida, Toshihiro Kusaka, Naohisa Yoshida, Ichiro Hirata, Takeshi Terai, Hiro O. Yamano, Kazuhiro Kaneko, Yuichiro Yamaguchi, Naoto Tamai, Naoko Nakano, Nana Hayashi, Mineo Iwatate, Hideki Ishikawa, Shigeaki Yoshida

Research output: Contribution to journalReview articlepeer-review


Many clinical studies on narrow-band imaging (NBI) have reported the usefulness of NBI magnifying endoscopy for qualitative and quantitative diagnosis of colorectal lesions in Japan. However, critical discussions have raised issues such as i) the presence of multiple terms for similar findings, ii) the necessity of taking into account surface patterns, and iii) differences in NBI findings between elevated (polypoid growth, PG) and superficial lesions (non-polypoid growth, NPG). The Japan NBI Expert Team (JNET) was constituted with the aim of establishing a universal NBI magnifying endoscopic classification of colorectal tumors (JNET classification) in 2011. To establish a universal NBI magnifying endoscopic classification of colorectal tumors, the JNET, consisting of 38 NBI expert members, was formed within the "Research Group of the National Cancer Center Research and Development Fund" (Yutaka Saito Group) in 2011. First, a working group was organized consisting of young but experienced researchers from six institutions in order to establish common evaluation criteria of the JNET classification. Consequently, normal/hyperplastic lesions were classified as type 1, low-grade adenomas as type 2A, high-grade adenomas as type 2B, and deep submucosal invasive cancers as type 3, and a magnifying NBI scale that took into account the vascular and surface patterns was created for both PG and NPG tumors. A web-based interpretation study was conducted by a JNET member in order to determine the NBI findings and diagnostic criteria to be used in the universal classification system in 2013. A JNET classification system was established based on the results of univariate/multivariate analyses using a modified Delphi method at a consensus meeting on June 6, 2014. The JNET classification consists of four categories of vessel and surface patterns, i.e., Types 1, 2A, 2B, and 3. Types 1, 2A, 2B, and 3 are correlated with the histopathological findings of hyperplastic polyp/sessile serrated polyp (SSA/P), low-grade intramucosal neoplasia, high-grade intramucosal neoplasia/superficial submucosal invasive cancer, and deep submucosal invasive cancer, respectively. At present, validation studies for the JNET classification have been proposed to be conducted.

Original languageEnglish
Pages (from-to)2314-2322
Number of pages9
Issue number11
Publication statusPublished - 2016

All Science Journal Classification (ASJC) codes

  • Radiology Nuclear Medicine and imaging
  • Gastroenterology


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