食道m3・sm1癌の質的・量的内視鏡診断

Present Status of Endoscopic Evaluation of m3 and sm1 Esophageal Cancer

要旨　m3癌50例（外科切除16例，粘膜切除34例）と，sm1癌22例（外科切除8例，粘膜切除14例）を検討対象とした．①リンパ節転移は，m3癌6％，sm1癌11％であった．脈管侵襲陽性率は，m3癌外科切除56％に対し粘膜切除29％，sm1癌外科切除88％に対し粘膜切除64％と，いずれも粘膜切除のほうが低率であった．②m3・sm1癌とも外科切除例は，隆起・陥凹が目立つため深達度を深く，逆に，粘膜切除例は，浅い陥凹が主体で，陥凹内の凹凸が少ないため，浅く診断する症例が多かった．③粘膜切除m3癌で，浅く診断した症例の半数はm3浸潤部が微小浸潤例であり，6mm以上の浸潤例はなかった．逆に，6mm以上の浸潤例では，m3以深の診断は全例可能であった．④m3浸潤部の形態は，陥凹内隆起（59％），辺縁隆起（3％），陥凹内のより深い陥凹（10％），微小浸潤のため形態不明（28％）であった．⑤m3浸潤範囲と脈管侵襲の関係では，浸潤部が3mm以下では脈管侵襲陰性，4.5mm以上では50％が脈管侵襲陽性であり，m3浸潤範囲の増大とともに脈管侵襲陽性率も高くなった．⑥粘膜切除m3癌にて脈管侵襲陽性10例中9例（90％）はm3以深と診断でき，粘膜切除前に脈管侵襲陽性の可能性は推測できた．

　The number of esophageal cancers reaching to the muscularis mucosae (m3) and those with slight invasion into the submucosa (sm1) has been small. Esophagectomy has been recommended, because the incidence of lymph node metastasis from them has been believed to be 10％. Patients with m3 and sm1 cancers have increased in these ten years. We reviewed seventy two cases (m3: 50 and sm1: 22) treated by surgery or endoscopic mucosal resection (EMR) at our hospital. Endoscopic evaluations before treatment, pathological diagnoses and clinical results were studied. The present status of the quality of endoscopic evaluation of m3 and sm1 esophageal cancers was discussed.

　Lymph node metastasis was noted in 6％ of all patients with m3 cancers and in 11％ of those with sm1 cancers. Esophagectomy was carried out on 24 patients and EMR on 48. In cases of patients who underwent esophagectomy, endoscopic findings suggested submucosal invasion, for they showed distinct elevation or depression. At the same time, patients who underwent EMR showed minimum elevation or depression which suggested m1 or m2 mucosal cancer. Histological study on m3 cancers revealed that the size of tumor with m3 invasion was less than 6 mm in cases which were underestimated as m1 or m2 cancers before treatment. All cases had been estimated correctly when tumor with m3 invasion were over 6 mm in size. In cases of m3 cancers, small granular elevation in a slightly depressed lesion (59％), slight elevation at the margin of the lesion (3％), and small and deeper depression in Ⅱc lesions (10％) suggested that it was the site of deeper invasion. Some patients showed no such distinct changes (28％). Microvascular permeation which suggested malignancy of m3 cancers, had a relationship with the size of tumor with m3 invasion. Malignancy was zero in cases of tumor with m3 invasion but which were less than 4.5 mm in size. However, malignancy was found in 50％ of such tumor over 4.5 mm in size.