Mo1689 LONG-TERM CLINICAL OUTCOMES OF PATIENTS WITH INDETERMINATE OR POSITIVE LATERAL MARGIN AFTER COMPLETE ENDOSCOPIC RESECTION AND RELATED FACTORS WITH RECURRENCE IN LARGE, SESSILE OR FLAT COLORECTAL POLYPS

Although incomplete resection in recognized as an important contributor to recurrence, recurrence rate in lesions with indeterminate or positive lateral margin on histology is unclear. We evaluated the long-term clinical outcomes of patients with indeterminate or positive lateral margin after complete endoscopic resection and related factors with recurrence in large, sessile or flat colorectal polyps. We retrospectively collected the data for 156 lesions (135 patients, males 102 (65.4%), mean age 64.9 years) with large size (≥10 mm), sessile or flat shape, indeterminate or positive lateral margin in histology and more than 24 months of follow-up intervals between Jan 2009 and Sep 2017. We retrospectively analyzed recurrence rate, time to recurrence, histology at recurrence and risk factors related with recurrence in these lesions. Of 156 neoplastic polyps, 97 lesions (62.2%) were indeterminate and 59 lesions (37.8%) were positive in lateral margin, respectively. During follow-up periods (24-86 months, mean 44.2), recurrence rate was 7.1% (11/156) and mean time to recurrence was 39.2 months (19.7-58.7). Histology at recurrence were low-grade adenomas (n=8), high-grade adenoma (n=1) and advanced cancers (n=2). Recurrence rate of cuff-off techniques were 3.15% (4/127) in en bloc, 9.09% (1/11) 2 piecemeal resection and 33.33% (6/18) in ≥3 piecemeal resection. All patients with recurrence except two patients with advanced cancer were treated by endoscopic resection. Two patients with advanced cancer in recurrence had morphologies of ≥deep submucosal cancer in initial endoscopic findings although low-grade adenoma in re-evaluation of initial histology. In analysis for risk factors related with recurrence, only ≥3 pieces of resection were significantly related with recurrence in both univariate analysis and multivariate analysis (OR 16.924 (95% CI 1.185-241.806), p=0.037) Following patients with indeterminate or positive lateral margin after complete endoscopic resection in large, sessile or flat colorectal polyp, recurrence rate was relatively low and time to recurrence was long than 12 months. Therefore, surveillance interval for these patients can be extended for more than 12 months. However, short-term and regular follow-up is mandatory in case of ≥3 piecemeal resections or suspected submucosal cancer in morphology because of risk of recurrence or interval cancer.Tabled 1Baseline Characteristics of PatientsParameterParameterAge (year)*64.97±8.67Resection method (%)Size (mm)*18.288±9.75Conventional EMR105 (67.3)F/U time (month)*44.21±16.77Hybrid EMR30 (19.2)Sex (%)ESD21 (13.5)Male102 (65.4)Cut-off technique (%)Female54 (34.6)En bloc127 (81.4)Margin status (%)2 Piecemeal11 (7.1)Indeterminate97 (62.2)≥3 Piecemeal18 (11.5)Positive59 (37.8)Initial histology (%)Location (%)LGD86 (55.1)Right88 (56.4)HGD21 (13.5)Left36 (23.1)SSA/P19 (12.2)Rectum32 (20.5)CIS30 (19.2)Polyp shape (%)Recurrence (%)Is64 (41)Yes11 (7.1)IIa92 (59)No145 (92.9)Complication (%)Yes14 (9)No142 (91)Data are expressed as mean±standard deviation Open table in a new tab Tabled 1Risk factors related with recurrence in univariate & multivariate analysisVariablesUnivariate analysisMultivariate analysisORp value95% C.IORp value95% C.IAge (years)1.0250.5080.753-1.1030.9680.5310.873-1.073SexFemale2.4250.1600.704-8.3482.9560.1790.608-14.369Size (mm)1.0520.0311.005-1.1020.9680.5170.877-1.068LocaztionRight (Ref.)0.3290.257Left0.3900.3920.513-7.4260.7020.7890.053-9.328Rectum1.9520.3260.513-7.4265.9360.1420.552-63.809ShapeIs0.8100.7450.227-2.8890.7110.7290.103-4.914Resection methodConventional EMR (Ref.)0.9160.846Hybrid EMR1.3470.6750.334-5.4290.5490.5630.072-4.199ESD0.0000.9980.000-0.0000.0000.9980.000-0.000Cut-off techniqueEn bloc (Ref.)0.0010.1112 Piecemeal3.0750.3350.313-30.1872.8740.4880.146-56.622≥3 piecemeal15.3750.0003.802-62.17016.9240.0371.185-241.806Complication4.5680.0421.058-19.7175.0900.1790.475-54.527Initial histologyLGD (Ref.)0.9370.553HGD0.5640.6020.066-4.8540.4250.4960.036-5.005SSA/P0.6270.6710.073-5.4201.3690.8150.098-19.141CIS0.8060.7950.158-4.1120.1540.1820.010-2.407Margin statusPositive3.1300.0790.875-11.1951.3060.8170.136-12.529F/U time (month)0.9800.2610.947-1.0151.0290.2400.981-1.080 Open table in a new tab