陥凹型早期胃癌の深達度診断―X線診断と超音波内視鏡との対比

The Depth of Invasion in Depressed Gastric Cancer Estimated by Roentgenography and Endoscopic Ultrasonography

要旨　陥凹型早期胃癌および陥凹型早期胃癌類似進行癌に対してX線検査および超音波内視鏡検査（EUS）を行い，両者の深達度診断を検討した．66例に対して行ったX線検査の診断能はm癌73.0％，sm癌64.7％，進行癌75％，全体で71.2％であった．一方，EUSでは胃癌の超音波像をtypeⅠ・Ⅱ・Ⅲ・A・Bの5型に分類し，更にtypeⅡをtypeⅡ-1，Ⅱ-2，Ⅱ-3の3型に亜分類した．typeⅠ，typeⅡ-1，typeⅡ-2はm癌，typeⅡ-3，typeⅢはsm癌，typeA，Bは進行癌と判定し，41例に対して行ったEUSの診断能はm癌83.3％，sm癌71.4％，進行癌100％，全体で82.9％であった．また，従来X線検査により深達度がsm以下とされた例で，EUSによりsmとpm以下との鑑別ができる例がみられた．両者とも微小浸潤は診断困難であった．

　Roentgenography and endoscopic ultrasonography were compared with respect to the accuracy in estimating the depth of ivasion in depressed gastric cancer. The depth of invasion was accurately estimated by roentgenography in 73.0% for the mucosal layer, in 64.7% for the submucosal layer, and in 75.0% for the advanced stage. On the other hand, the accuracies were 83.3%, 71.4%, and 100%, respectively, by endoscopic ultrasonography.

　Ultrasonographic findings in gastric cancer were classified into seven types. According to this classification, gastric cancers showing type Ⅰ, Ⅱ-1, or Ⅱ-2 were diagnosed as mucosal cancers, those showing type Ⅱ-3 or Ⅲ as submucosal cancers, those showing type A or B as advanced cancers.

　It was difficult to differentiate submucosal invasion from deeper invasion beyond the proper muscle layer by roentgenography. Ultrasonography, however, could clearly make such differentiation in a few cases. In any case, microscopic invasion was not satisfactorily diagnosed by either method.