275 Outcome Over 5 Years of Minimally Invasive Treatment of Early Gastric Cancer Beyond Endoscopic Submucosal Dissection Ga Won Song*, Suk Pyo Shin, Weon-Jin Ko, Jun Hwan Yoo, Duk Hwan Kim, Kim Wonhee, Kwang Hyun Ko, Joo Young Cho, Ki Baik Hahm, Sung-Pyo Hong, Pil Won Park, Jun-Hyung Cho Digestive Disease Center, Soonchunhyang University Hospital, Seoul, Korea (the Republic of); Digestive Disease Center, CHA Bundang Medical Center, CHA University, Seongnam-si, Korea (the Republic of) Background/Aims: The aim of this study was to evaluate the long term outcomes of combined endoscopic submucosal dissection (ESD) with laparoscopic lymph node dissection (LLND) and endoscopic full-thickness resection (EFTGR) with laparoscopic regional lymph node dissection (hybrid natural orifice transluminal endoscopic surgery, hybrid NOTES) for early gastric cancer (EGC). Methods: This is a retrospective analysis at a single tertiary referral center. A total of 23 patients with EGC underwent combined ESD with LLND and hybrid NOTES for early gastric cancer beyond endoscopic submucosal dissection between February 2007 and August 2009. Then the patients received periodic endoscopic follow-up and metastatic surveys over 5 years. The main outcome measures were curability (curative or non-curative), recurrent rate, and survival rates. Results: The curative resection rate of all cases was 95.7% (ESD with LLND 90.0% vs. hybrid NOTES 100%, respectively). Incomplete resection was shown in 1 (tumor-positive vertical margin). Histologically, 11 cases were mucosal cancers, and 12 were submucosal cancers. And there were 12 undifferentiated cancers. The median tumor size was 3.4 cm (range, 1.25.7cm) in long diameter. The lymphovascular invasion was found in 3 cases with 1 lymph node metastasis. 5 patients underwent additional gastrectomy because of tumor-positive margins or treatment-related complications. During over 5 year follow-up periods, none showed local recurrence or lymph node metastasis. The 5 year overall survival rates and disease free survival of the patients was100% in both. Conclusion: Combined ESD with LLND and hybrid NOTES showed favorable long term clinical outcomes. They could be utilized as a bridge between ESD and gastrectomy in selected patients with a risk of lymph node metastasis. 276 Incidence and Risk Factors of Metachronous Gastric Cancer After Endoscopic Resection and Successful Helicobacter pylori Eradication: Results From a Large-Scale, Multicenter Cohort Study in Japan Genki Mori*, Takeshi Nakajima, Ichiro Oda, Kiyoshi Asada, Taichi Shimazu, Nobutake Yamamichi, Takao Maekita, Chizu Yokoi, Mitsuhiro Fujishiro, Takuji Gotoda, Masao Ichinose, Toshikazu Ushijima Endoscopy Division, National Cancer Center Hospital, Tokyo, Japan; Division of Epigenomics, National Cancer Center Research Institute, Tokyo, Japan; Epidemiology and Prevention Group, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan; Department of Gastroenterology, University of Tokyo, Tokyo, Japan; Second Department of Internal Medicine, Wakayama Medical University, Wakayama, Japan; Department of Gastroenterology and Hepatology, National Center for Global Health and Medice, Tokyo, Japan; Department of Gastroenterology and Hepatology, Tokyo Medical University, Tokyo, Japan Introduction: A previous multicenter prospective randomized study from Japan showed that Helicobacter pylori (HP) eradication reduced the development of metachronous gastric cancer (MGC) after endoscopic resection (ER) for early gastric cancer (GC) from 40.5 to 14.1 cases per 1000 person-years. MGC is, however, still detected in a certain rate even after successful HP eradication, few studies have evaluated the incidence and risk factors of MGC. Aims: To clarify the incidence and risk factors of MGC in the cases after ER for early GC with successful HP eradication. Methods: Participants comprised 594 patients (485 men, 109 women; median age, 66 years; range, 36-79 years) who underwent ER for early GC and successful HP eradication in one of three institutions (National Cancer Center Hospital, The University of Tokyo Hospital and Wakayama Medical University Hospital) between 1999 and 2010. Annual endoscopic surveillance was performed after ER. HP infection was diagnosed using the C urea breath test, serology and culture of biopsy samples. Positive results in at least one of these three tests were considered as evidence of HP infection. The status of baseline gastric mucosal atrophy at the time of successful HP eradication was assessed endoscopically according to the Kimura-Takemoto classification. MGC was defined as a GC newly detected at least 1 year after successful HP www.giejournal.org Vol eradication. Results: Median follow-up period after successful HP eradication was 4.5 years (range, 1.0-11.4 years). During the follow-up period, 93 MGCs were detected in 79 patients. Kaplan-Meier analysis showed a linear increase in the cumulative incidence of MGC; the incidence of MGC was 29.9 cases per 1000 person-years (Fig. 1). Multivariate analysis by using Cox proportional hazard modeling revealed that male sex, open-type gastric mucosal atrophy, and multiple GCs before HP eradication were independent risk factors for MGC (Table 1). Conclusion: Careful and continuous surveillance endoscopy for MGC is required even after successful HP eradication, particularly in male patients, those with extensive gastric mucosal atrophy, and multiple GCs before HP eradication. Multivariate analysis for the risk of MGC ume 81, No. 5S : 2015 GASTROINTE Number STINAL E Hazard Ratio