Long-Term Outcome Of Endoscopic Resection In Patients With Superficial Esophageal Squamous Cell Carcinoma Invading The Muscularis Mucosae Or Superficial Submucosa

multiple SEC 154; previous RT 53. Sixty cases met the criteria of difficult ESD. The procedure time was longer than 120 minutes in 43 (6.3%) cases. Perforations and pneumomediastinum occurred in 8 (1.4%) and 8 (1.4%) cases, respectively. Piecemeal resection occurred in 3 (0.4%) cases. Vertical margin was positive or cannot be assessed in 14 (2.1%) cases. Multivariate logistic regression analysis revealed that left wall in esophagus (OR 2.15 [95% CI 1.17-3.91], pZ0.014), circumference of the lesion 1/2 (OR 5.06 [95% CI 2.40–11.34], p<0.001), were two independent factors related to difficult procedure. Conclusion: Predictive factors for technical difficulty in esophageal ESD were left wall and circumference more than half of the esophagus. These results may contribute to a better selection of suitable lesions according to each endoscopist’s skill. Tu1216 Long-TermOutcome of Endoscopic Resection in Patients With Superficial Esophageal Squamous Cell Carcinoma Invading the Muscularis Mucosae or Superficial Submucosa Nakatani Yukihiro*, Seiichiro Abe, Ichiro Oda, Satoru Nonaka, Haruhisa Suzuki, Shigetaka Yoshinaga, Saowonee Ngamruengphong, Ken Kato, Yoshinori Ito, Yuji tachimori, Yutaka Saito Endoscopy Division, National Cancer Center Hospital, Tokyo, Japan; Division of Gastroenterology & Hepatology, Johns Hopkins Medicine, Boltimore, MD; Radiation Oncology Division, National Cancer Center Hospital, Tokyo, Japan; Gastrointestinal Medical Oncology Division, National Cancer Center Hospital, Tokyo, Japan; Esophageal Surgery Division, National Cancer Center Hospital, Tokyo, Japan Background: According to the 2012 guidelines by the Japan Esophageal Society, endoscopic resection (ER) is relatively indicated for superficial esophageal squamous cell cancer (SESCC) invading to muscularis mucosae (MM) or superficial submucosa 200mm (SM1) given the potential risk of nodal metastasis. However, little is known about the long-term outcomes in those patients with longer than 5year follow-up periods. Thus, this study aimed to clarify long-term outcomes of ER in patients with SESCC with MM or SM1 in depth. Methods: A total of 1030 patients with SESCC underwent ER with negative deep margin between 2000 and 2012. Of these, this retrospective study included 129 patients who met the following criteria: 1) solitary index SESCC histologically invaded into MM or SM1; 2) no advanced malignancy in other organs. Treatment strategy after ER was determined on a multidisciplinary evaluation by endoscopists, surgeons and gastrointestinal oncologists. In this study, additional surgery or prophylactic chemoradiotherapy (CRT) is considered in patients with LVI or SM invasion. Prophylactic CRT is generally given to radiation therapy of 41.4-45 Gy elective nodal irradiation dose combined with 5FU and CDDP. Those patients were generally followed up with esophagogastroduodenoscopy and computed tomography surveillance on an annual or biannual basis to identify metachronous esophageal squamous cell carcinoma (SCC), lymph node and distant metastasis. Results: Patient characteristics were as follows: median age 66 years, male/female: 107/22, depth of invasion (MM/SM1): 107/22, LVI (+/-): 18/111, 70 and 59 patients underwent endoscopic mucosal resection (EMR) and endoscopic submucosal resection (ESD), respectively. En bloc resection rate was 70.5%. None developed local recurrence after ER during median follow-up period of 66 (range 0159) months. Among 91 with MM invasion without LVI, 71 were observed without any additional treatment and 20 underwent prophylactic CRT. Of these 91, only 1 recurred nodal and distant metastasis who received prophylactic CRT after piecemeal EMR. Among 16 with MM invasion with LVI, of 7 who were observed, 1 developed nodal metastasis. Of 9 who underwent prophylactic CRT, 2 developed nodal metastasis. 6 out of 22 with SM1 invasion were observed and 16 underwent prophylactic CRT. None developed recurrence. The 5-year overall survival rates of patients with MM with and without LVI and SM1 cancer were 96.3%, 83.1% and 96.3%, respectively. The 5-year disease specific survival rates were 100%, 90.0% and 100%, respectively. A total of 41 metachronous esophageal SCC were found in 30 patients during the follow up period, the 3-year and 5-year cumulative incidence of metahcrounous esophageal SCC were 17.2% and 24.0%, respectively. Conclusions: ER has curative potential for SESCC that invades MM without lymphovascular involvement. Long term outcome of patients after ER Number Relapse, median 5-year 5-year 5-year cause www.gie journal.org n (%) follow