切開・剥離法（ESD）に必要な胃癌術前診断―X線診断

Preoperative X-ray Diagnosis of Gastric Carcinoma, Which is Necessary for the Performance of Endoscopic Submucosal Dissection (ESD)

要旨　切開・剥離法（ESD）に必要な胃癌術前X線診断につき概説した．ESD施行の可否にかかわらず病変および周辺粘膜が胃小区レベルまで描出された良質なX線画像が必要であり，また病変の平面的，立体的な所見を忠実に表したX線画像が必要である．深達度診断に関しては病変の特徴を十分に把握した上で癌のsm以深浸潤によって生じた所見（因果関係に基づく所見）と，それ自体は癌の深部浸潤を表してはいないが，過去の臨床病理学的な検討をもとに統計的にsmあるいはそれ以深への癌浸潤と相関する所見（相関関係に基づく所見）に分けて診断を行う必要がある．粘膜内浸潤範囲の診断においては胃癌治療ガイドライン内の病変についてはほぼ問題ないものの，適応拡大する上では未分化型におけるIIb進展，胃型の分化型のX線所見を十分に理解したうえで診断することが必要となる．

　We gave an outline of preoperative X-ray diagnosis of gastric carcinoma, which diagnosis is necessary for the performance of endoscopic submucosal dissection (ESD). Whether the ESD method is adopted or not, fine quality X-ray images of the lesion and its peripheral mucosa, where even the gastric area is shown, are necessary. An X-ray image that accurately represents the lesion plane and the solid mass of the lesion itself is also needed.

　Needless to say consideration of the characteristics of the lesion is most important in deciding the depth of cancer invasion. It is also necessary to consider the following two factors ; 1) the findings due to submucosal or deeper layer invasion (the findings based on causal relationship) and 2) the findings correlated with submucosal or deeper layer invasion as shown by statistic analysis in previous clinicopathologic investigation (the findings based on comparison with statistical data).

　To diagnose the exent of intramucosal invasion of the carcinoma, the pertinent guidelines are usually sufficient. However, before extending the use of the ESD, careful attention is needed to assess the progress of undifferentiated and differentiated IIb type of gastric carcinoma, and of the gastric mucin phenotype after due consideration of their X-ray images.