848 - A Population Level Analysis of Adhesive Small Bowel Obstruction after Abdominal Surgery: Significant and Sustained Advantage of a Laparoscopic Approach

BACKGROUND:It is presumed that the non-oncological index cholecystectomy (IC) leading to discovery of incidental gallbladder cancer (IGBC) does not significantly impact survival.This study compares the outcome of non-IGBC vs IGBC to identify patients that may have a negative impact from failure of performing upfront radical cholecystectomy, METHODS: Clinical and pathologic features of non-IGBC and IGBC patients treated with curative intent at two centers (USA and Chile) during 1999-2016 were compared.Patients with T1 and T4 tumors and preoperative jaundice were excluded.T2 IGBC and non-IGBC were stratified by the presence of hepatic side tumor at IC which has been shown to be a predictor of worse survival (AJCC 8 th). Predictors of disease-specific survival (DSS) were analyzed.RESULTS: The study included 196 patients: 151 (77%) with IGBC and 45 (23%) with non-IGBC.Major liver resection, operative mortality, major complication, N+ status and R1 resection were comparable.DSS rate in IGBC vs non-IGBC was 60% vs 50% at 3 years (p= 0.064).Further, 118 (78%) IGBC patients and 18 (48%) non-IGBC patients had T2 disease.Eleven (10%) T2b IGBC and 7 (41.2%)T2b non-IGBC patients had tumor at the hepatic side.T2 and T3 IGBC vs non-IGBC had similar survival (T2: DSS rate at 3 years 63% vs 81%, p=0.730;T3: DSS rate at 3 years 29% vs 46%, p=0120).However, T2b IGBC patients had lower DSS rates than T2b non-IGBC (DSS rate at 3 years, 31% vs 85%; p=0.019).Further, T2b IGBC patients DSS was inferior when the time interval between IC and OER is >60 days.(DSS rate at 3 years, 16% vs 85%; p=0.004).In multivariate analysis of T2 patients, predictive factors for poor DSS are hepatic side tumor in IGBC patients (hazard ratio (HR), 3.2; 95% CI, 1.1-9.4;p=0.032) and N1 status (HR, 2.3; 95% CI, 1.2-4.5;p= 0.011).CONCLUSIONS: Patients with T2b IGBC benefit from single operation even when patients are rendered disease free during a follow up oncologic extended resection.Efforts should be made to identify T2 IGBC preoperatively to refer these patients to centers with expertise in oncologic resection for GB cancer.