Mo1718 THE POCKET-CREATION METHOD FACILITATES ENDOSCOPIC SUBMUCOSAL DISSECTION OF COLON TUMORS

Colonic ESD is considered more challenging than rectal ESD because of poor maneuverability of the endoscope due to physiological flexion, peristalsis and respiratory movements. Some patients ultimately need surgical resection due to endoscopic technical difficulties even though the lesions are not deeply invasive. We previously reported that the pocket-creation method (PCM) facilitates ESD of colorectal laterally spreading tumor, non-granular type, frequently associated with submucosal fibrosis. The PCM facilitates a tangential approach to the muscularis and fixes the tip of the endoscope in the submucosal pocket to synchronize with respiratory movements, allowing a safe and efficient dissection. The aim of this study is to assess the usefulness of the PCM for colonic ESD compared with conventional methods (CM) regardless of lesion shape. A total of 887 colorectal lesions were resected by ESD between April 2010 and January 2017 at Jichi Medical University Hospital. Of 887 lesions, 271 rectal lesions, 72 lesions smaller than 20mm in diameter and one non-neoplastic lesion were excluded. This is a retrospective chart review of the remaining 543 colon lesions in 512 patients. We divided them into a PCM group (n=280) and a CM group (n=263). The primary outcome measurement was en bloc resection rate. Secondary outcome measures included (1) R0 resection (en bloc resection with histopathologically negative resection margin); (2) adverse events; (3) dissection time (min); (4) dissection speed (mm2/min). As shown in the Table, the PCM achieved significantly higher en bloc resection rates (P=0.0006) and pathological R0 resection rates (P=0.02) than CM. Lesion locations and diameters were similar. Dissection time was shorter than CM but not significantly (P=0.33). Dissection speed was significantly faster with PCM than CM (P=0.00007). The incidence of adverse events was similar (perforation and late delayed bleeding, 1.8% vs. 3.8% (P=0.15), 2.1% vs. 1.1% (P=0.36)) ESD using PCM increases the rate of en bloc resection and R0 resection and allows rapid dissection for the treatment of colon tumors.Tabled 1Clinical characteristics of treatment resultsPCMn=280CMn=263P valueLocation: Cecum/ Ascending/ Transverse/ Descending/ Sigmoid55/ 82/78/15/ 5054/ 81/65/ 10/ 530.78En bloc resection rate280/ 280 (100%)253/ 263 (96%)0.0006Lesion size mm, median (range)32 (20-97)32 (20-125)0.73Dissection time, median (range) (min)58.5 (16-316)63.0 (7-425)0.33Dissection speed, median (range) (mm2/min)21 (5-75)18 (3-89)0.00007Pathological Lesion Depth: Intramucosal/ pT1a/ pT1b or deeper/ Unevaluated247/ 18/14/1228/ 24/ 11/ 00.45Pathological R0 resection rate255/ 280 (91%)224/ 261 (86%)0.02Perforation5 (1.8%)10 (3.8%)0.15Delayed bleeding6 (2.1%)3 (1.1%)0.36 Open table in a new tab