Is positive histologic surgical margin associated with overall survival in patients with resectable gallbladder cancer?

Background: Achieving microscopically negative (R0) surgical margins in gallbladder cancer often requires a partial hepatectomy with associated risk of morbidity and potential to delay adjuvant therapy. Prior studies on the importance of margin status in resectable gall bladder cancer include small numbers of patients with positive (R1) resection margins and are underpowered. Methods: We queried the National Cancer Database to identify patients undergoing resection of gallbladder adenocarcinoma between 2004 and 2015. Patients presenting with metastatic disease, those who received neoadjuvant therapy, and those with fewer than 3 lymph nodes assessed were excluded. 1:1 propensity score matching was used to develop cohorts undergoing either R0 or R1 resection, matched for demographic, pathologic, and facility characteristics. Kaplan–Meier analysis was used to assess the association between margin status and overall survival. Results: A total of 1,439 patients met inclusion criteria; 1,285 underwent R0 and 154 underwent R1 resection. On Kaplan–Meier analysis of propensity-matched cohorts, patients undergoing R0 resection had a median overall survival that was 18 months longer than those undergoing R1 resection (34.6 ± 2.0 months vs 16.3 ± 1.7 months, P