胃癌治療ガイドラインの適応外病変となる早期胃癌の診断―内視鏡診断（超音波内視鏡を含む）

Endoscopic and EUS Diagnosis of Early Gastric Cancers Outside the Indications of the Guideline for Endoscopic Mucosal Resection

要旨　分化型早期胃癌379例（M癌283例，SM癌96例）のうち，長径2cmを超え，UL（－）のM癌38例とSM癌33例の内視鏡検査（超音波内視鏡検査）に対する深達度および浸潤度診断を行った．内視鏡診断によるM癌の診断能は感度86.5％，特異度85.2％，正診率77.5％であった．M癌をM癌と正診できなかった4例のうち3例は病変の丈の高い例であった．一方，SM癌をM癌とした5例は粘膜下層内への粘膜筋板からの浸潤距離が浅く，浸潤範囲も狭い例であった．粘膜下層内への浸潤範囲が狭いと，病変の大きさが広くなるに従い，相対的に粘膜下層内での癌の割合が小さくなるため診断は不良になると考えられた．

　We studied the endoscopic diagnosis for the depth and extension of cancerous invasion in early gastric cancers whose longer diameter exceeded 2 cm without ulceration. Out of the differentiated type of early gastric cancer 379 cases (M cancer 283 cases, SM cancer 96 cases), 38 cases of M cancer and 33 cases of SM cancer were selected for review. Endoscopy sensitivity was 86.5％, specificity was 85.2％, accuracy was 77.5％. The three cases of M cancer which were not diagnosed as M cancer by endoscopy, were elevated type cancers. On the other hand, five cases of SM cancer which were misdiagnosed as M cancer had invaded into the submucosal layer only slightly. In the cases where cancerous invasion into the submucosal layer was slight, diagnosis for the depth of cancerous invasion according to the increase of the size of a lesion was found to increase in difficulty.