Between December 2007 and January 2013, 18 patients underwent ESD for tumors (six adenomas with HGD and 12 differentiated-type EGCs) occurring in the remnant stomach after distal gastrectomy at the Samsung Medical Center. ESD for EGC was performed based on the Japanese Gastric Cancer Treatment Guidelines [5]. All ESDs were performed by three experienced endoscopists (B.H.M., J.H.L., and J.J.K.). We retrospectively reviewed the outcomes after ESD in 18 consecutive patients who were identified from a prospectively collected database. ESD procedures of our institution are described in detail elsewhere [6]. In brief, ESD consisted of three steps: (1) injecting fluid into the submucosal layer to separate it from the proper muscle layer, (2) circumferential cutting of the mucosa surrounding the lesion, and (3) submucosal dissection of the connective tissue under the lesion with an electrosurgical knife. During the procedure, surgical staples were removed by using coagrasper or alligator. We mainly used IT knife (KD-610L; Olympus, Tokyo, Japan) or IT knife-2 (KD-611L; Olympus) for submucosal dissection. However, in cases of submucosal fibrosis around the suture line, submucosal dissection was performed with needle knife (MTW Endoscopy, Wesel, Germany) or dual knife (KD-650L; Olympus) after sufficient submucosal injection around the fibrotic area. The study protocol was approved by the Institutional Review Board at Samsung Medical Center.

Esophagogastroduodenoscopy (EGD) with a biopsy was performed 2 months after ESD to confirm healing of the ESD-induced artificial ulcer and to exclude the presence of any residual tumor. In EGC cases, EGD with a biopsy and abdominal computed tomography (CT) were performed every 6 months thereafter for 3 years to detect local, metachronous, or extragastric recurrence. After 4 to 5 years of performing ESD for EGC, EGD with a biopsy and abdominal CT were performed annually. In cases of adenoma with HGD, EGD with a biopsy was performed annually.

En bloc resection was defined as resection of the tumor in one piece with no endoscopically residual tumor. R0 resection was defined as tumor resection with no histological evidence of cancer cells on the lateral or vertical margins. In EGC cases, resection was judged as curative when all of the following conditions were fulfilled: well-differentiated or moderately differentiated EGC or papillary EGC, en bloc resection or piecemeal resection with successful reconstruction, negative lateral resection margins, negative vertical resection margin, no lymphovascular invasion and: (1) tumor size ≤2 cm, mucosal cancer, no ulcer in tumor (EGC meeting absolute indication); (2) tumor size >2 cm, mucosal cancer, no ulcer in tumor; (3) tumor size ≤3 cm, mucosal cancer, ulcer in tumor, or (4) tumor size ≤3 cm, SM1 cancer (submucosal invasion depth <500 μm from muscularis mucosa layer). En bloc resection and R0 resection rates were assessed in both the adenoma with HGD and differentiated-type EGC cases. Curative resection rate was assessed only in EGC cases. Bleeding was defined as (1) intraoperative massive bleeding that required blood transfusion, (2) postoperative bleeding that required blood transfusion or endoscopic or surgical intervention because of hematemesis or melena, or (3) a greater than 2 g/dL decrease in the hemoglobin level after the procedure. Perforation was diagnosed when the mesenteric fat or intra-abdominal space was observed directly during the procedure (frank perforation), or if free air was found on performing plain chest radiography after the procedure without a visible gastric wall defect noted during the procedure (microperforation).

Table 1 summarizes the clinicopathologic characteristics of the enrolled patients and tumors. Median tumor size was 13 mm. Two-thirds of the lesions were located on the body, and half were located on the suture line due to the previous gastrectomy (17 Billroth I and 1 Billroth II gastrectomy) (Fig. 1). No lesions involved the anastomosis site. The median period between previous gastrectomy and ESD was 80 months (range, 14 to 207) in cases of Billroth I and was 13 months in case of Billroth II.

Table 2 summarizes the clinical outcomes of ESD for tumors occurring in the remnant stomach after distal gastrectomy. En bloc resection, R0 resection, and en bloc with R0 resection rates were 88.9%, 100%, and 88.9%, respectively. Two EGCs were resected in piecemeal fashion with one lesion located on the suture line. Among 12 enrolled patients with EGC, curative resection was achieved for 11 cases (91.7%). Eight EGCs met the absolute indication criteria, and three met expanded indication criteria. One patient had EGC with a lymphatic invasion and a submucosal invasion up to 900 μm and underwent completion total gastrectomy after ESD. Perforation occurred in one patient and was successfully managed by endoscopic closure with metallic clips and conservative management. In this patient, the lesion was not located on the suture line. Tumors located on the suture line showed longer procedure time than tumors not involving the suture line, although the difference between the two groups did not reach statistical significance (p=0.218). During the median 47.5 months of follow-up, no local, metachronous, or extragastric recurrence was seen for either EGC or adenoma with HGD lesions.