早期胃癌のEUS深達度診断

Endoscopic Ultrasonographic Diagnosis of the Depth of Invasion of Gastric Cancer

要旨　EUSによる正常胃壁の基本層構造と早期胃癌深達度診断の基本について述べ，さらに早期胃癌のEUS診断能について検討した．過去5年間に当センターで切除された早期胃癌1,601病変のうちEUSが施行された568病変の描出不良率は11.6％（66病変）であった．また，描出不良例を除いた502病変で，EUSおよび内視鏡の深達度診断能を肉眼型，深達度別に検討した．その結果，描出不良率はL領域で高かった．描出可能な病変では，EUSは7.2％で内視鏡診断の不一致を補正するのに有用であり，oversugeryを避ける観点からは，特に内視鏡診断SM2の病変にEUSを施行するのが有用と考えられた．

　We evaluated the ability of EUS for diagnosing the depth of invasion of early gastric cancer. Among 568 lesions that we studied by EUS, 66 lesions（11.6％）were unable to reveal clear images. Furthermore, the number of the lesions that revealed poor EUS images was especially high in L region. Moreover, among 502 lesions with clear EUS images, we were able to correct the depth of invasion of early gastric cancer in 36 lesions（7.2％）, which had been misdiagnosed by conventional endoscopy.

　In conclusion, EUS is useful for lesions diagnosed as SM2 by conventional endoscopy. It contributes to the avoidance of unnecessary surgery.