食道胃接合部腺癌の範囲診断—内視鏡の立場から

Diagnosis of the Lateral Margin of Esophagogastric Cancer

要旨●近年，本邦において食道胃接合部腺癌は増加傾向にあり，内視鏡治療適応病変も多く発見されている．病変を一括切除するためには，正確な範囲診断が極めて重要である．今回食道胃接合部腺癌の範囲診断に関して，Barrett食道癌と胃噴門部癌に分け比較検討した．2012年1月〜2020年7月の期間に，当院でESDを行った食道胃接合部腺癌93例94病変を対象とした．食道胃接合部腺癌の定義は「食道癌取扱い規約 第11版」に則り，西分類を用いて食道胃接合部の上下2cm以内に癌腫の中心がある病変とした．検討項目は患者背景，病変の臨床病理学的特徴，範囲診断正診率（通常観察，NBI拡大観察），扁平上皮下進展の有無とした．結果，Barrett食道癌と胃噴門部癌の両病変において，通常観察と比較してNBI拡大観察が範囲診断に有用であった（Barrett食道癌：58% vs. 92%，胃噴門部癌：68% vs. 100%）．扁平上皮下進展は，Barrett食道癌で有意に多く，病変とSCJの位置関係が関与していることが示唆された．また，酢酸撒布後にみられる白色変化を観察することで，扁平上皮下進展は術前に診断可能であった．

　With the advancement in endoscopic equipments, superficial carcinoma of the esophagogastric junction is more frequently detected and more likely to be treated endoscopically in Japan. An accurate diagnosis of the lateral extension of the lesion is important to resect the lesion en bloc. In this study, we investigated the horizontal extension of esophagogastric cancer.

　We retrospectively reviewed cases treated with endoscopic submucosal dissection from January 2012 to July 2019. Esophagogastric cancer was defined according to the Nishi classification. Lesions that met the pathological criteria were defined as BC and those that did not meet these criteria were classified as GC. Between the BC and GC, the patient's background, clinicopathological features, the rate of lateral extent（WLI［white light imaging］and NBI［narrow band imaging］magnification）, and the presence of cancerous extension under the squamous epithelium were compared. Previous studies report that the endoscopic finding of SWS（small white signs）after acetic acid staining represents the existence of CUS in BC. Therefore, we investigated the endoscopic images of all these lesions to determine the presence of SWS.

　There were 94 cases of esophagogastric cancer, including 69 GCs and 25 BCs. In both the groups, NBI magnification（BC：92.9% vs. GC：100%）was more useful than WLI（BC：58% vs. GC：68%）for the lateral diagnosis of the lesion. Lateral extension under the squamous epithelium was significantly more common in BC. This result was considered to be largely related to the distance between the lesion and SCJ. By observing the SWS after acetic acid staining, lateral extension under the squamous epithelium could be diagnosed preoperatively.