Barrett食道癌の深達度診断

Diagnosis of Invasion Depth of Superficial Barrett's Esophageal Adenocarcinoma

要旨●Barrett食道癌において，術前深達度診断は治療方針の決定における重要な因子である．Barrett食道癌の深達度診断に用いるモダリティは，通常内視鏡検査，画像強調（IEE）拡大内視鏡，超音波内視鏡検査（EUS），X線造影検査などが挙げられる．通常内視鏡検査では病変の形態や大きさ，厚みや硬さ，色調などを観察する．凹凸のほとんどない0-IIb型や0-IIa型，基部に細いくびれを有する0-I型，浅く平滑な陥凹を有する0-IIc型は粘膜内癌を示唆する所見である．拡大観察では酢酸を用いたIEEが範囲診断や存在診断，組織型診断に有用である．EUSやX線造影検査も深達度診断の助けとなるが，本邦ではSSBE由来のBarrett食道癌が多く，食道胃接合部という局在のために詳細な観察が難しい症例も多い．

　The diagnosis of the invasion depth of superficial Barrett's esophageal adenocarcinoma is important for the determination of therapeutic strategy because the invasion depth markedly correlates with lymph node metastasis. WLI（white-light imaging）, magnifying IEE（imaging with image enhanced endoscopy）, EUS（endoscopic ultrasonography）, and X-ray are used for diagnosing the invasion depth ; of these, WLI is the most important modality that is used to observe the shape, size, thickness, hardness, and color change. Fat 0-IIb and 0-IIa lesions, 0-I lesions with a narrow base, and 0-IIc lesions with a flat, smooth depression indicate mucosal cancer. Furthermore, IEE using acetic acid is useful in diagnosing the lateral extent of the lesions. Barrett's esophageal adenocarcinoma occurring from short-segment Barrett's esophagus, which constitutes the majority of Barrett's adenocarcinoma cases in Japan, is often difficult to closely examine by EUS and X-ray because of its location at the esophagogastric junction.