Oral (pre-recorded)
OB02 Biliary: Gallbladder Cancer 
Selection of Presentations from Abstract Submissions
OB02-01 Prognostic Significance of Tumor Location in T2 Gallbladder Cancer: A Korea Tumor Registry System-BiliaryPancreas (KOTUS-BP) Database Analysis
Seungeun Lee, Korea, Republic of

S. Lee, Y.-S. Choi
Surgery, Chung-Ang University College of Medicine, Korea, Republic of

Objective: The aims of this study were to investigate the clinical features and clinical outcomes of T2 gallbladder cancer (GBC) according to tumor location and determine the prognostic significance of tumor location and an appropriate surgical strategy for T2 GBC.
Methods: Using Korea tumor registry system- biliarypancreas (KOTUS-BP) database, between 2000 and 2014, a total 707 patients with T2 GBC who underwent curative resection were enrolled.
Results: 309 patients were T2a, and 398 patients were T2b. The incidence of lymph node metastasis in T2b tumor group was 37.5% and significantly higher than that of T2a tumor group (29.5%). After a median follow-up period of 43 (range 3-189) months, the 5-year disease-specific survival (76% vs. 69%, p=0.019) and disease-free survival of the T2a group were better than those of the T2b group (69% vs. 57%, p=0.002). However, there was no significant difference in survival between Stage IIa (T2aN0) and Stage IIb (T2bN0) (83% vs.74%, p=0.149). There were no significant survival differences between T2a and T2b groups according to whether hepatic resection was performed or not. Multivariate analysis revealed that lymph node metastasis was the only significant poor prognostic factor
(hazard ratio 2.966, 95% confidence interval 1.960-4.489, p < 0.001).
Conclusion: In T2 GBC, simple cholecystectomy and lymph node dissection for staging work-up could be recommended irrespective of tumor location. Postoperative adjuvant therapy should be considered, because lymph node metastasis was a significant poor prognostic factor, systemic recurrence was more common, and recurrence occurred more frequently among patients with lymph node metastasis.
OB02-02 Staging Laparoscopy in Gallbladder Cancer Is Infrequently Used Despite High Rates of Peroperatively Diagnosed Disseminated Disease
Elise de Savornin Lohman, Netherlands

E. de Savornin Lohman1, H. Kuipers2, J. Erdmann3, B. Groot Koerkamp4, D. Braat5, J. Hagendoorn6, F. Daams7, M. de Boer2, P. de Reuver1, National Gallbladder Cancer Collaborative
1Surgery, Radboudumc, Netherlands, 2Surgery, UMCG, Netherlands, 3Surgery, Amsterdam UMC, AMC, Netherlands, 4Surgery, Erasmus MC, Netherlands, 5Surgery, LUMC, Netherlands, 6Surgery, UMC Utrecht, Netherlands, 7Surgery, Amsterdam UMC, VUmc, Netherlands

Introduction: Staging laparoscopy (SL) is recommended before attempting resection in patients with gallbladder cancer (GBC). The aim of this study was to assess the yield of SL in terms of reducing unnecessary surgical exploration and to delineate factors associated with disseminated disease (DD).
Material and methods: Data were collected from all GBC patients undergoing SL and/or surgical exploration in eight Dutch academic hospitals from 2000-2019. Outcomes after laparotomy with or without SL were assessed and factors predictive for DD were identified.
Results: A total of 210 patients was included; SL was performed in 43 (20%). SL was more frequently performed in patients with tumor invasion in the liver on pre-operative imaging (53% vs 30%, p=0.014). DD was detected by SL in 8/43 patients (19%). Of the 35 patients with SL that underwent surgical exploration, 25(72%) were resected and in 10 patients (28%) DD was diagnosed during laparotomy. Accuracy of SL for detecting DD was 44%(8/18). Of 167 patients without SL, resection was performed in 125(75%) and in 44(25%) DD was found. DD was most frequently detected at the hepatic hilum (16/44, 36%) and the peritoneum (10/44, 23%). In total, 62 (30%) patients had DD. Liver invasion on imaging was associated with high rates of DD (50/76, 66%) and predictive for DD in multivariate analysis (OR 12.5,P=0.021).
Conclusion: SL in GBC is infrequently used despite a 30% chance of occult metastatic disease. In patients with liver invasion on imaging risk of DD is 66% and SL be recommended.
CharacteristicSL (N=43)No SL (N=167)P-value
Age (mean/range)64 (45-86)66 (33-81)0.391
ASA >29 (21%)41 (25%)0.690
Cholecystitis0 (0%)10 (6%)0.220
Primary Sclerosing Cholangitis3 (7%)6 (4%)0.394
Gallbladder polyp3 (7%)8 (5%)0.700
N1 disease (imaging)8 (35%)28 (36%)0.906
Liver invasion (imaging)21 (53%)45 (30%)0.014
Pre-operative jaundice18 (42%)54 (32%)0.160
Pre-operative biliairy drainage21 (49%)56 (34%)0.063
[Baseline characteristics of patients with and without SL.]

[Patient flow and surgical outcomes.]
OB02-03 Clinical Implication of PD-L1 Expression in Gallbladder Cancer
Yutaka Sato, Japan

Y. Sato, S. Kuboki, H. Yoshitomi, K. Furukawa, T. Takayashiki, S. Takano, D. Suzuki, N. Sakai, M. Ohtsuka
Department of General Surgery, Chiba University, Graduate School of Medicine, Japan

Introduction: Programmed death ligand-1 (PD-L1) expression has been established as a prognostic factor for various solid tumors, but is not well understood in gallbladder cancer (GBC). This study was designed to evaluate PD-L1 expression in GBC and investigate its association with clinicopathological factors, tumor-infiltrating immune cells and survival outcomes.
Methods: The expression of PD-L1 was detected by immunohistochemistry from 94 GBC patients who underwent R0/R1 resection at our institution between 2003 and 2016. Tumor-infiltrating CD8+ T cells or CD163+ positive macrophages were assessed at invasive front of tumor, tumor stroma and intraepithelial, respectively. To evaluate the cytotoxic activity of CD8+ T cell, the expression of Perforin and Granzyme B was also assessed using immunohistochemistry.
Results: The expression of PD-L1, Perforin and Granzyme B was identified in 38 patients (40.4%), 29 patients (30.9%) and 20 patients (21.3%), respectively. High PD-L1 expression was associated with male gender, high preoperative CA19-9 level, lymphatic invasion, venous invasion, lymph node metastasis and liver metastasis. High PD-L1 expression was related to poorer OS (p=0.0046) and DFS (p=0.0011). In addition, CD163+ macrophage infiltration of tumor was positively correlated with PD-L1 expression. Moreover, high CD8+ TIL group at invasive front of tumor had better OS (p=0.011) compared to low CD8+ TIL group. However, high PD-L1 was also related to poor prognosis in this subgroup.
Conclusions: PD-L1 expression is a useful biomarker for advanced GBC. The subgroup of high PD-L1 with high CD8+ TIL at invasive front of tumor would be potential therapeutic target for PD-1/PD-L1 checkpoint inhibitors.
OB02-04 Impact of Pre-operative Positron Emission Tomography - Computed Tomography for Management of Gallbladder Cancer
Anshuman Pandey, India

A. Pandey1,2, D. Kumar1
1Surgical Gastroenterology, RMLIMS, Lucknow, India, 2Surgical Gastroenterology, KGMU, Lucknow, India

Background: Prognosis of gallbladder carcinoma is poor; surgery with R0 resection remains the only chance for long-term survival for these patients.Extensive evaluation is mandatory to accurately define the tumor stage,regional lymph nodes and distant metastases to identify those patients who may benefit from surgery.The purpose of this study was to assess the diagnostic value of PET-CT in relation to a conventional imaging modality,CECT for patients with gallbladder cancer.
Methods: This study was prospective observational study conducted at tertiary care institute.Seventy patients with suspected gallbladder cancer who underwent both PET-CT and MDCT for initial staging were included in our study.Results of these two imaging modalities for evaluating primary tumors, regional lymph nodes and distant metastases were compared with the final diagnoses based on histopathological examination.
Results: PET-CT demonstrated no significant advantage over MDCT for the diagnosis of a primary tumor.PET-CT showed a significantly higher accuracy (90.8vs.80.0%,P=0.04) than MDCT for diagnosis of regional lymph node metastasis. PET-CT showed significantly higher sensitivity (92.3vs.61.5%,P=0.04) than MDCT in the diagnosis of distant metastasis.Addition of PET-CT changed management in 10 patients(14.3%).In seven patients,radical resection was avoided due to presence of distant lymph nodal disease or distant metastases diagnosed on PET-CT.In three patients with suspicious CT finding,PET was negative for malignancy.
Conclusions: In patients with potentially recectable gallbladder carcinoma on primary imaging, PET-CT may be helpful in detecting distant nodal metastasis and unsuspected metastatic disease that may preclude patients from surgical resection.Addition of preoperative PET-CT in staging of gallbladder carcinoma, also result in change of management in significant number of patient.
OB02-06 Is There a Role for Selective Histological Examination of Gallbladders Following Cholecystectomy for Benign Gallbladder Disease? Results of S-GALLOP Study
Ibrahim Enemosah, United Kingdom

I. Enemosah1, J. Denson1, S. Aroori1, K. Dutt2
1University Hospital Plymouth NHS Trust, United Kingdom, 2General Surgery, University Hospital Plymouth NHS Trust, United Kingdom

Introduction: Considering the shortage of number of Pathologists working in the National Health Service (NHS), and the low incidence of incidentally detected gallbladder cancers (IGBC) in the UK, selective gall bladder histology could potentially save money and time. This study evaluates the histopathologic assessment of patients that underwent elective cholecystectomies for benign gallbladder disease over 10-year period.
Methods: This is a retrospective study of 8043 patients who underwent elective cholecystectomies at University Hospital Plymouth NHS trust (UHPNT) between January 2009 to December 2018. Clinical details and histopathologic data were evaluated to identify patients with IGBC, including a cost analysis.
Results: There were 32 cases [1 in 250 (0.4%), 23 females] IGBC during the study period. Seventeen (53.1%) patients had abnormal gall bladder wall thickening on gross morphology. In the UK, approximately 70,000 cholecystectomies are performed annually for benign disease. Extrapolating our institution rate to the rest of the UK, a total of 280 cholecystectomy specimens would have had IGBC. Which means, 69,720 gall bladder specimens potentially would not require histopathologic processing. The cost of processing a gallbladder specimen is £74.94, and NHS could potentially save £5.224 million per year. Based on this, the hepatobiliary and pathology units in UHPNT are researching the development of a prospective protocol for selective gall bladder histology.
Conclusion: The outcome shows that to identify one case of IGBC about 250 specimens would have to be analysed by the histopathology team. The potential time and cost savings of a prospective protocol would be future breakthrough.
OB02-07 Neoadjuvant Chemotherapy in Locally Advanced Unresectable Carcinoma Gall Bladder (ENACT Trial): A Novel Beginning in a Tertiary Centre in North India
Saurabh Galodha, India

S. Galodha1,2, P. Mahajan2, A. Panwar2, V.K. Sharma2, D.K. Verma2
1G I Surgery & Liver Transplantation, All India Institute of Medical Sciences, India, 2Surgery, Indira Gandhi Medical College, India

Introduction: Locally advanced Gall Bladder Cancer (LAGBC) is usually unresectable and presents with dismal prognosis. The role of neoadjuvant chemotherapy (NACT) in LAGBC is still not fully established. In our study we look for effect of NACT in LAGBC in terms of response and survival.
Methods: All patients of Carcinoma GB (CaGB) admitted in department of Surgery over one year period were included. Patients with LAGBC given 4 cycles of Gemcitabine and Cisplatin based NACT after histopathological confirmation. Response was assessed using RECIST criteria and patients with complete/partial response were subjected to surgery. Perioperative morbidity and mortality was noted. Patients with successful surgery received further adjuvant chemotherapy. Patients' survival was noted in follow up.
Results: 45 patients of CaGB were analysed. 8 patients (17.7%) received NACT after histopathological confirmation. None of the patients had serious adverse events during NACT. 6 patients (75%) showed partial/complete response. During surgery, 1 patient had metastatic disease, 3 patients underwent extended cholecystectomy (EC), 1 underwent EC with hepaticojejunostomy and 1 required multivisceral resection. Major morbidity (Clavien Dindo 3 or more) was seen in only 1 patient in terms of bile leak. There was no mortality. On median follow up of 15 months, 4 patients were alive while one had recurrence and later died due to cardiac arrest.
Conclusions: Neoadjuvant chemotherapy provides hope to patients of LAGBC and should be used in patients with good functional status. Larger multicenter studies should be done to establish a defined role of NACT in this dreaded disease.