Su1820 The Distribution of Gastric Diseases Based Upon National Cancer Endoscopic Screening Program in Korea for 7 Years

Abstract

[Background and Aim] Since the technical advance and the development of new devices, endoscopic submucosal dissection (ESD) is widely utilized for the treatment of superficial esophageal squamous cell neoplasms (ESCNs). In the treatment of ESCNs without nodal metastasis, ESD achieves the similar clinical outcomes to those of esophagectomy and chemoradioherapy and is much less invasive than them. The intensive studies of histopathological analysis of surgically resected ESCNs have proven that the cases of non-invasive carcinoma (EP, carcinoma in situ) and intra-mucosal invasive carcinoma limited to the lamina propria mucosae (LPM) had an extremely low risks of lymph node and distant metastasis. Based on these findings, the Japanese guideline for the treatment of esophageal cancer states that both EP and LPM cases are suitable for ESD. On the other hand, the lymph node metastasis rate of ESCNs invading to the muscularis mucosae (MM) including both with and without lymphovascular invasion has been reported as 7-10 %. Thus, ESD treatment had not been positively recommended for MM cases. However, it is assumed that MM cases without lymphovascular invasion have no lymph node metastasis. Thus, there exists the possibility that MM cases without lymphovascular invasion can be suitable for ESD. In this study, therefore, we evaluated expanded ESD indication to the MM cases without lymphovascular invasion, by analyzing surgically resected specimens histopathologically and investigating the clinical outcomes both after surgery and ESD of MM cases without lymphovascular invasion. [Methods] MM cases without lymphovascular invasion surgically treated between January 2001 and December 2010 (11 cases) and those treated with ESD between January 2006 and August 2012 (30 cases) at Akita University Hospital were enrolled in this study. [Results] In the detailed histopathological analysis of the surgically resected specimens of 11 MM cases without lymphovascular invasion, no lymph node metastasis was detected. No recurrence or metastasis developed in any of these 11 cases until today. In the analysis of the ESD-treated, 30 MM cases were proven to have no lymphovascular invasion by the histopathological examination of the specimens endoscopically resectd en bloc. Then, no additional therapy such as chemoradiotherapy was performed for these cases. However, all of the 30 cases are still alive without recurrence or metastasis during the followup period (4-81 months, average 33.8 months). [Conclusion] Our current study elucidated that MM cases without lymphovascular invasion has no risk of lymph node metastasis, and clinical outcomes of the ESD-treated MM cases without lymphovascular invasion are extremely satisfactory. These data suggest that ESD indication for superficial ESCNs treatment can be expanded to the MM cases without lymphovascular invasion.