Mo1101 IS ENDOSCOPIC SUBMUCOSAL DISSECTION A FEASIBLE TREATMENT FOR ESOPHAGOGASTRIC JUNCTION CANCER?

Abstract

In Japan, endoscopic submucosal dissection (ESD) is widely performed for superficial esophagogastric junction (EGJ) cancer, including gastric cardiac adenocarcinoma (GCA) and Barrett’s esophageal adenocarcinoma (BEA). However, the absolute indication of ESD for EGJ cancer is not yet established. Therefore, accumulation of EGJ cancer cases treated using ESD is required to establish the definitive criteria. The aim of this study was to elucidate the long-term outcome of ESD and the effectiveness of our treatment strategy for EGJ cancer. A retrospective, single-center study of 141 patients (mean age, 73.2 ± 10.2 years; male/female, 113/28; GCA/BEA, 123/18) who underwent ESD for EGJ cancer from January 2004 to October 2014 was conducted. EGJ cancer was defined as Siewert type II adenocarcinoma, and included GCA and BEA. At our hospital, curative resection was performed when the depth of invasion was <T1b-SM2 (T1b-SM2: an invasion depth of the submucosal [SM] layer >500 μm in GCA or >200 μm in BEA), and both lymphovascular involvement (LVI) and poor differentiation at the invasion front (INFc) were negative. Surgery was performed in the patients with non-curative resection as much as possible. Medical records were used to obtain follow-up patient data. The overall survival (OS) and disease-specific survival rates were evaluated. Furthermore, the clinical course of the patients with non-curative resection was closely analyzed. The en bloc resection rate was 93.6% (132/141). The ESD complication rate was 8.5% (5/141), without fatality. The invasion depth was T1b-SM2 in 19 cases (GCA, 16; BEA, 3). The tumor differentiation was poor in 1 case, pap in 3, moderate in 11, and well in the remaining 126. The median follow-up period (range) was 73 (4-161) months. The 5-year OS and disease-specific survival rates were 88.3% and 99.0%, respectively. Twenty patients underwent non-curative resection (GCA/BEA, 15/5; T1b-SM2, 19; LVI or INFc positive, 6). Of these, 13 patients underwent surgery and only 2 showed a remnant tumor in the resected specimen. With additional surgery, disease control was favorable with no later metastases. Only 2 patients died of EGJ cancer (GCA, 1; BEA, 1). Both had an invasion depth of T1b-SM2 and did not undergo additional surgery. LVI was positive in only 1 of these cases. Metastases were only found in these 2 cases. The long-term outcome of ESD for EGJ cancer was favorable. ESD is a feasible treatment for EGJ cancers with an invasion depth <T1b-SM2. With additional surgery, disease control was favorable even in the patients with non-curative resection. Our treatment strategy based on T1b-SM2, LVI, and INFc seems effective and valid.