早期胃癌の術前診断（EMR適応病変を中心に）―EUSの立場から

Endoscopic Ultrasonographic Diagnosis of the Depth of Invasion of Early Gastric Cancer for Determing the Indication for Endoscopic Mucosal Resection (EMR)

要旨　比較的小さく，潰瘍性変化を伴わず，深達度も浅いEMR適応病巣では，EUS診断能は，肉眼型，部位にかかわらず良好であったが，内視鏡と比べて明らかな差は認めなかった．また，EUS，内視鏡ともに正診したものは全病巣の91.2％と高く，内視鏡診断に対するEUS診断の上乗せ効果はさほど期待できなかった．すなわち，EUSはきれいに描出されればその診断能は客観的で説得力があるが，ことEMRの適応決定においては必須の検査とは言い難かった．

　The diagnostic ability of EUS for discerning the depth of invasion of early gastric cancer was compared with that of endoscopy in 173 patients with 182 lesions of early gastric cancer. In size, macroscopic type, microscopic type and depth of ulceration, the lesions indicated their suitability for EMR. Because of difficulty in evaluation of the depth of invasion less than 1 mm, we diagnosed the lesions such as M-SM1 (SM invasion was less than 1 mm) and SM2 (SM invasion was more than 1 mm).

　The depth of invasion was correctly diagnosed in 166 lesions (91.2％) by not only EUS but also endoscopy.

　As regards macroscopic type or site of the lesion, the accuracy rate of the diagnosis of the depth of invasion by EUS was high, but it was hardly different from that of endoscopy.

　We encountered five lesions (2.7％) of early gastric cancers which were correctly diagnosed by EUS, though inaccurately diagnosed by endoscopy. On the other hand, we encountered four lesions (2.2％) which were correctly diagnosed by endoscopy, though inaccurately diagnosed by EUS.

　In conclusion, it was hard to say that EUS examination was necessary for determining the indication for EMR.