超音波内視鏡検査による胃分化型SM1癌の深達度診断

Endosonographic Diagnosis of the Depth of Cancerous Invasion of Differentiated Type Gastric Cancer

要旨　分化型SM胃癌84例（SM1癌25例，SM2癌59例）に対する超音波内視鏡検査による診断能をみた．正診率は全体で77.4％，SM1癌で56.0％，SM2癌で86.4％であった．UL（－）病変48例の正診率は72.9％，SM1癌で50.0％，SM2癌で80.6％であった．UL（－）病変でのEUSにおける第3層の変化を不整型，欠損型，混合型に分類したところ，SMと正診できたSM1癌はすべて不整型であった．不整型は欠損型，混合型に比較して粘膜下層内での深達距離が浅く，混合型に比較して粘膜下層内での病変の拡がりが狭かった．粘膜筋板下端より750μm浸潤していればSM病変と診断可能であった．

　We discussed the accuracy of endoscopic ultrasonography (EUS) for diagnosis of the depth of cancerous invasion of differentiated type gastric cancer, especially early gastric cancer with submucosal invasion. The accuracy of EUS is 77.4％ in submucosal cancer, 56.0％ in SM1 cancer, 86.4 in SM2 cancer. The accuracy of EUS on cancer without ulceration is 72.9％, 50.0％ in SM1 cancer, 80.6％ in SM2 cancer. Three types of cancer were subjected to EUS, the irregular type, the defected type and the combined type, but the only SM1 cancer which we could diagnose by using EUS was the irregular type. The irregular type is slighter than the other two types, and narrower than the combined type. The lesions which invaded 750μm beyond the muscularis mucosae were able to be diagnosed as submucosal invasion by EUS.