POEM patients, although the difference was not statistically significant (26.4% vs 18.1%, pZ0.13). The following adverse events occurred at similar rate between the POEM and PD groups: Pneumothorax (4% versus 2.5%, pZ0.06), chest pain (0.53% versus 0.4%. pZ0.07), and significant clinical bleeding (2% versus 1.2%, pZ0.19). Inadvertent mucosotomy occurred in 5% of POEM patients, while perforation occurred in 1.4% of PD patients. Conclusion: POEM is more efficacious than PD in the treatment of patients with achalasia during short-term and long-term follow-up. Abnormal esophageal acid exposure occurs more frequently after POEM although GERD symptoms do not differ between the two groups. Figure 1. Clinical Success of POEM and PD over 3 months, 12 months, 2 years and 5 years. 472 A RANDOMIZED CONTROLLED TRIAL COMPARING PERORAL ENDOSCOPIC MYOTOMY (POEM) VERSUS LAPAROSCOPIC HELLER MYOTOMY WITH FUNDOPLICATION IN THE TREATMENT OF ACHALASIA Eduardo T. Moura* 1 , Galileu F. Farias 1 , Lara M. Coutinho 1 , Aureo Delgado 1 , Diogo T. de Moura 1,2 , Ary Nasi 1 , Natália S. Queiroz 1 , Shri K. Jayanthi 3 , Rubens A. Sallum 1 , Ivan Cecconello 1 , Paulo Sakai 1 , Eduardo G. de Moura 1 1 Gastroenterology, University of Sao Paulo Medical School, São Paulo, Brazil; 2 Gastroenterology, Brigham and Women’s Hospital - Harvard Medical School, Boston, MA; 3 Radiology, University of Sao Paulo Medical School, São Paulo, Brazil Introduction: Achalasia is a benign esophageal motor disorder characterized by insufficient lower esophageal sphincter (LES) relaxation and absence of esopha- geal peristalsis. The treatment may be endoscopic, pharmacological or surgical. Currently, the laparoscopic Heller myotomy (LHM) is the gold standard treatment but the peroral endoscopic myotomy (POEM) has gained popularity because of its safety and efficacy profile. A recent systematic review and meta-analysis showed POEM to be as effective and safe as LHM for achalasia. We conducted a randomized clinical trial to assess the efficacy and safety of POEM versus LHM in patients with achalasia. Methods: This is a randomized clinical trial including patients with manometric findings consistent with achalasia and no obstructive cause without prior therapy were randomly assigned to either LHM or POEM from a single tertiary center. Demographic data, procedure info, clinical success, Eckardt score, height of barium-contrast column, LES pressure, reflux esophagitis, adverse events, operative time and length of hospital stay were collected. Clinical success was considered as an Eckardt score  3 at 1 year. Student T’s test, Chi-square and Logistic regression analyses were conducted. Results: Forty patients were enrolled (26 M, mean age 44.5  13.7) from March 2016 to January 2017. We performed POEM in 20 patients and LHM in other 20. There was no statistical difference between groups regarding clinical success (95% in the POEM group vs 100% in the LHM group, pZ 1.00). Both groups presented significant reduction in Eckardt scores compared to baseline (0.50 vs 8.00 in the POEM group, p< 0.001 ; 0.00 vs 8.00 in the LHM group, p< 0.001), height of barium-contrast column 5 minutes after barium ingestion (7.97 vs 15.69 in the POEM group, p< 0.001; 8.66 vs 14.92 in the LHM group, p< 0.001) and LES pressure (11.38 vs 24.45 in the POEM group, p< 0.001; 9.73 vs 23.91 in the LHM group, p< 0.001) at 1 year follow-up. Adverse events (AE) rates were similar for both groups: empyema requiring thoracic drainage (1 in LHM group); mucosal defects requiring endoscopic clipping (3 in POEM group). There was no statistical difference between groups regarding Eckardt score (pZ 0.242), height of barium-contrast column (pZ 0.276), LES pressure (pZ 0.347) and AEs rate (pZ 0.605). Patients undergoing POEM were more likely to develop erosive esophagitis (64.6% vs 11.1%, pZ 0.002). Operative time was significantly lower for POEM (95.7 min vs 218.7 min, p< 0.001). There were no differences between POEM and LHM in length of hospital stay (3.40 days vs 3.95 days, pZ 0.483). Results are summarized in table 1. Conclusion: POEM is as effective and safe as LHM for the treatment of achalasia with a shorter operative time. However, POEM is related with a higher esophagitis rate. 473 ENDOSCOPIC FULL-THICKNESS RESECTION IN COLORECTAL CANCER Armin Küllmer* 1 , Julius Mueller 1 , Karel Caca 2 , Patrick Aepli 3 , Dani Dakkak 4 , Brigitte Schumacher 4 , Anne Glitsch 5 , Claus Schäfer 6 , Ingo Wallstabe 7 , Christopher Hofmann 8 , Andreas Erhardt 9 , Benjamin Meier 2 , Dominik Bettinger 1 , Robert Thimme 1 , Arthur Schmidt 1 1 Department of Medicine II, Medical Center, University of Freiburg, Faculty of Medicine, University of Freiburg, Germany, Freiburg, BW, Germany; 2 Department of Gastroenterology and Oncology, Klinikum Ludwigsburg, Ludwigsburg, Germany, Ludwigsburg, BW, Germany; 3 Gastroenterology and Hepatology Unit, Luzerner Kantonsspital, Lucerne, Switzerland, Luzern, Luzern, Switzerland; 4 Department of Gastroenterology, Elisabeth-Krankenhaus Essen, Germany, Essen, Nordrhein-Westfalen, Germany; 5 Department of Medicine, Division of Interdisciplinary Endoscopy, University Greifswald, Germany, Greifswald, Mecklenburg-Vorpommern, Germany; 6 Medical Clinic II, Klinikum Neumarkt, Neumarkt, Germany, Neumarkt, Bayern, Germany; 7 Department for Gastroenterology, Hepatology, Diabetology und Endocrinology, Klinikum St. Georg gGmbH, Leipzig, Germany, Leipzig, Sachsen, Germany; 8 Department of Gastroenterology, Katholisches Klinikum Mainz, Germany, Mainz, Rheinland-Pfalz, Germany; 9 Department for Gastroenterology, Hepatology und Diabetology, Petrus-Krankenhaus, Wuppertal, Germany, Wuppertal, Nordrhein-Westfalen, Germany Background & Aims: Current international guidelines recommend endoscopic resec- tion for T1 colorectal cancer (CRC) with histological low-risk features and oncologic resection for those at high-risk of lymphatic metastasis. Exact risk stratification is therefore crucial to avoid under- as well as over-treatment. Endoscopic full-thickness resection (EFTR) has shown to be effective for treatment of non-lifting benign lesions. In this multicenter, retrospective study we aimed to evaluate efficacy, safety and clinical value of EFTR for early colorectal cancer. Methods: Records of 1234 patients undergoing EFTR for various indications at 96 centers were screened for eligibility. 156 patients with histological evidence of adenocarcinoma were identified. This cohort comprised 64 cases undergoing EFTR after incomplete resection of a malignant polyp (Group 1) and 92 non-lifting lesions (Group 2). Endpoints of the study were: technical success, R0-resection, adverse events and successful discrimination of high- versus low risk tumors. Results: Technical success was achieved in 144/156 (92.3%), mean procedural time was 42 minutes. R0 resection was achieved in 112/156 (71,8%). Subgroup analysis showed a R0 resection rate of 87.5% in Group 1 and 60,9% in Group 2 (p<0.001). Severe procedure-related adverse events were recorded in 3,9%. Discrimination between high- vs. low-risk tumor was successful in 155/156 cases (99.3 %). 84,1% of Group 1 were identified as low-risk lesions, whereas 16,3% in group 2 had low-risk features. In total 53 patients (34%) underwent oncologic resection due to high risk features whereas 98 patients (62%) were followed endoscopically. Conclusions: EFTR in early colorectal cancer is technically feasible and safe. It allows exact histological risk stratification and avoid surgery for low-risk lesions. Prospective studies are required to further define indications for EFTR in malignant colorectal lesions and to evaluate long-term outcome. AB84 GASTROINTESTINAL ENDOSCOPY Volume 89, No. 6S : 2019 www.giejournal.org Abstracts