Su1562 Comparison of Clinical Outcomes Between the Endoscopic Submucosal Dissection and the Transanal Endoscopic Microsurgery for Early Rectal Cancers

Endoscopic submucosal dissection has a therapeutic advantage for certain colonic lesion and enables endoscopists to achieve a higher en-bloc resection rate, resulting in enhanced curability and more accurate histopathological assessment. The aim of this study is to compare endoscopic submucosal dissection(ESD) with transanal endoscopic microsurgery(TEM) for early rectal cancers in terms of the clinical outcomes and the safeties. Between 2007 and 2010, 91 patients with early rectal cancer were treated with ESD(n=25) or TEM(n=66) in Samsung Medical Center. Their medical records were retrospectively reviewed and their clinical outcomes and safeties were compared. In baseline comparison, there were no significant differences in demographic features and tumor characteristics regarding pre- and post-treatment histology. But macroscopic appearances of tumors were different between both groups. 16(64%) cases were laterally spreading tumors in ESD group and 47(71.2%) cases were polypoid lesion in TEM group(p=0.000). Treatment outcomes regarding en-bloc resection rate(92% vs 98%, p=0.183), R0 resection rate(96% vs 97%, p=1.000) and local recurrence rate(0% vs 3% p=1.000) were comparable between both groups. In perspective of procedure related variables, TEM needed general anesthesia in most of cases(88%), but every ESD procedure was performed under conscious sedation. Routine uses of antibiotics were required in TEM group due to full thickness layer excision but selected cases had required antibiotics in ESD group.( 100% vs 36%, p=0.000) ESD showed shorter total procedure time or operation time(median 67min(25-150) vs 90min(40-310), p=0.019) and shorter in-hospital days(median 3days(2-8) vs 5days(3-17), p=0.000). Both groups did not showed significant differences in bleeding(0% vs 0%) or perforaton/post-op leakage(4% vs 1.5%, p=0.476) rates. In the perforated case in the ESD group, the lesion was confined to the rectal wall and was not extended into the free peritoneal space, and was treated conservatively without surgery but the post-op leakage case in the TEM group underwent open abdominal surgery. For early rectal cancers, en-bloc and R0 resection rates of ESD were comparable with TEM. Both modalities are safe and appropriate treatment options for early rectal cancers, however, ESD has advantages in terms of its minimal invasiveness, shorter hospital stay, no requirement of general anesthesia and no necessity of routine antibiotic use.TableTreatment outcomesTreatment outcomesESD (n=25)TEM (n=66)P-valueEn-bloc resection rate23 (92.0%)64 (98.5%)0.186R0 resection rate24 (96.0%)64 (97.0%)1.000Local recurrence0 (0%)2 (3.0%)1.000p-value by χ2 test or Fisher's exact test Open table in a new tab TableComplication ratesComplicationsESD (n=25)TEM (n=66)P-valueBleeding0 (0%)0 (0%)-Perforation/post-op leakage1 (4%)1 (1.5%)0.476Anal disorder0 (0%)1 (1.5%)1.000p-value by Fisher's exact test Open table in a new tab