内視鏡的粘膜切除術を施行した胃sm癌―外科的追加手術施行例

Clinical Study of Invasive Gastric Cancer Patients Who Underwent Surgical Operations after Endoscopic Mucosal Resection (EMR)

要旨　腺腫および早期癌436病変に対して内視鏡的粘膜切除術(EMR)を施行し，14例(3.2％)にsm浸潤が認められ，うち7例に対して外科的追加切除が行われた．追加切除例のうちsm₁癌の1例のみに遺残が確認されたが，他の6例では遺残が認められなかった．分化型sm₁癌ではその垂直方向浸潤の程度によっては追加切除の必要がない症例があり，今後sm₁癌に対する内視鏡的切除術(ER)の適応拡大についての検討が期待される．また，術前にEMRの適応病変であるか否かをX線的・内視鏡的に十分に検討し，手技に習熟していれば，外科的追加切除となる症例は決して多くないことを強調した．

　Recently, endoscopic mucosal resection (EMR) method has made it possible to carry out radical resection for small gastric mucosal cancers in resectable cases. The indications for performing EMR instead of surgery were determined pathologically as follows; (1) Eleveted type of cancer measuring 2 cm or less in size, (2) Depressed type of cancer without ulceration measuring 1 cm or less in size, (3) Differentiated type of mucosal carcinoma. Following those indications, from 1988 the EMR method has been used for 436 lesions as a radical treatment for gastric adenomas (n=234) and well-differentiated adenocarcinomas (n=202). Of the 202 lesions, 14 lesions (6.9%) were diagnosed histopathologically as invasive (sm) cancers. Endoscopic follow-up was made in four patients but no residual lesion was demonstrated. Seven patients with sm_1～2 cancers underwent surgical operation after EMR. In six cases with positive submucosal invasion, cancer cells were not found in surgical specimens. However, remains of cancer cells were found in mucosa in only one case. In these days, submucosal invasion of carcinomas has been divided into three degrees according to the grade of invasion of EMR treatment, the invasion depth: sm₁, sm₂ and sm₃. From the standpoint of EMR treatment, invasion depth sm1 should be properly defined as a depth unassociated with lymph node metastasis. For differentiated adenocarcinoma, a range 200～400 μm from the lowest limit of the muscularis mucosae corresponded to the above mentioned sm₁. However, we cannot diagnose precisely the degree of submucosal invasion prior to EMR, so we don't think that EMR is an effective cure for clinically detectable invasive cancers.