NBIによる早期食道癌診断―white lightとnarrow band imagingを用いた非拡大内視鏡検査による早期食道癌診断のsensitivity

Diagnosis of Early Esophageal Squamous Cell Carcinoma with Narrow Band Imaging System─Sensitivity of Conventional Endoscopy with White Light and Narrow Band Imaging for the Detection of Early Esophageal Squamous Cell Carcinoma

要旨　白色光（WL）およびNBIによる食道扁平上皮癌（SCC）診断率の差を検討するために以下の研究を行った．早期SCC 53病変のWL, NBI画像と非腫瘍部の画像27枚をランダムに配列したWL 80枚，NBI 80枚の画像集を制作し，無情報で8名の内視鏡医に読影を依頼した．熟練者群のsensitivity平均値（範囲）はWL 88.7％（84.9～92.5），NBI 92.5％（88.7～96.2），初心者群ではWL 68.2％（50.9～79.2），NBI 64.8％（37.7～79.2）であった．熟練者群では腫瘍径10mm以下でWL 64.3％, NBI 85.7％とNBIが高値であったが，11mm以上ではWL 92.4％，NBI 93.5％と差はなかった．一方，初心者群では，腫瘍径にかかわらずWLとNBIのsensitivityに差はなかった．NBIは熟練者が小SCCを発見する際に有用であったが，初心者群での有用性は証明されず，初心者がNBIを使いこなすには十分な教育が必要と思われた．

　The aim of this study was to compare the sensitivity of White Light（WL）and Narrow Band Imaging（NBI）for the diagnosis of early esophageal Squamous Cell Carcinoma（SCC）.

　Eighty WL endoscopic pictures and eighty NBI endoscopic pictures containing 53 SCC and 27 non neoplastic areas were arranged at random. Eight endoscopists were required to circle the place where they diagnosed as SCC on the endoscopic picture without any other information.

　The average sensitivity of two expert endoscopists was 88.7% in WL, and 92.5% in NBI and that of six beginners'was 68.2% in WL, and 64.8% in NBI. The sensitivity of the expert group for the detection of tiny SCC 10mm or less was 64.3% in WL and 85.7% in NBI and that for SCC 11mm or more was 92.4% in WL and 93.5% in NBI.

　On the other hand, amongst the beginners, there was no difference between their sensitivity under WL and NBI, regardless of the tumor size.

　NBI was useful for the detection of small SCC in the expert group, but not useful in the beginners group. Beginners need to be trained enough before they can use NBI for the Esophageal SCC.