Barrett食道腺癌（表在癌）の拡大観察—基本と最新知見

Magnification Endoscopy for the Detection and Diagnosis of Superficial Barrett's Esophagus-related Neoplasms

要旨●本邦においてBarrett食道腺癌は依然まれであるが，GERDの罹患率上昇に伴い，今後，Barrett食道および腺癌の増加が憂慮されている．進行したBarrett食道腺癌の予後は不良であり，内視鏡検査による早期発見が重要である．本邦ではBarrett食道腺癌の大多数が内視鏡観察の難しい食道胃接合部に局在する．よって，その早期発見には通常観察のコツと拡大観察を駆使した高い内視鏡診断に習熟する必要がある．本稿では，筆者らの経験と国内外の臨床研究成果に基づいたBarrett腺癌の早期発見に肝要と思われる基本テクニックから，最近提唱された日本食道学会Barrett拡大内視鏡分類までを解説したい．

　BE（Barrett's esophagus）is a precursor of esophageal adenocarcinoma, which, although still rare in Japan, is one of the most rapidly increasing cancers in Western countries. However, the prevalence of gastroesophageal reflux disease has significantly increased over the past few decades in Japan, possibly leading to an incremental rise in BE and the associated inherent risk of adenocarcinoma.

　Given the poor prognosis of late-stage BEN（BE-related neoplasms）, it is important to detect BEN at an early stage. However, endoscopic identification of eBEN（early-stage BEN）is to date not reliable and inaccurate, making targeted biopsy only by conventional endoscopy extremely difficult. During the last decade, newly developed imaging technologies, such as narrow band imaging combined with magnification endoscopy, have enabled early identification of eBEN lesions. This article focuses on how to accurately detect and diagnose eBEN using magnification endoscopy.