内視鏡的食道粘膜切除後にm3・sm1と判明した癌への対応

Clinical and Pathological Study on Esophageal Cancers Reaching to the Muscularis Mucosae and Upper Third of the Submucosa

要旨　食道表在癌のうち，深達度m3・sm1症例は，リンパ節転移が10～15％に認められる．なかでも，病巣内のごく一部で粘膜筋板に接したり，sm浸潤範囲が狭い症例では，病巣の大部分を占める深達度の浅い病巣として診断され，粘膜切除の適応となりやすい．m3・sm1癌についてのアンケート調査の結果をみると，病変の大きさが大きいもの，m3またはsm浸潤範囲が広いもの，低分化型扁平上皮癌，infγの浸潤を示すものは，脈管侵襲陽性率が高い．また，脈管侵襲の程度が高くなるに従い，リンパ節転移の陽性率が上昇することがわかった．内視鏡的粘膜切除治療後にm3あるいはsm1と判明した場合は，①m3あるいはsm1浸潤部の大きさ，②脈管侵襲の有無③浸潤様式，④先進部での組織型について検討する必要がある．①脈管侵襲陽性例，②infγ症例，③低分化型扁平上皮癌の症例では，リンパ節転移の可能性を考慮して，可能な症例に対しては追加治療を行うべきである．

　Clinical management of superficial esophageal cancers which have invasion reaching to the muscularis mucosae (m3) and the upper third of the submucosa (sm1) is controversial. Incidence of lymph node metastasis from such cancers is approximately 10%, while it is 0% in those limited to the lamina propria mucosae, and 40% in submucosal cancers reaching to the middle and lower third of the submucosa. Some patients with m3 and sm1 cancers havc undergone endoscopic mucosal resection (EMR) because of clinical evaluation that cancer invasion might be limited to the lamina propria mucosae. In this paper, clinical and pathological characteristics of m3 and sm1 cancers were discussed. Twentyfive institutes contributed to this study and 356 cases (m3: 161 cases and sm1: 195 cases) were included. Clinical and pathological characteristics of cases with lymph node metastasis was discussed. The incidence of lymph node metastasis increased in accordance with the size of lesions, the depth of invasion into the muscularis mucosae and invasion into the upper third of the submucosa. Poorly differentiated squamous cell carcinomas especially those with distinct infiltrative growth into the surrounding tissues had lymph node metastases. Histological findings concerning these factors will facilitate decision making about additional treatments for m3 and sm1 cancers after endoscopic mucosal resection.