Does Intraoperative Frozen Section and Revision of Margins Lead to Improved Survival in Patients Undergoing Resection of Perihilar Cholangiocarcinoma? A Systematic Review and Meta-analysis

Background: Perihilar cholangiocarcinoma (PHC) is a rare malignancy that arises at the biliary confluence. Achieving a margin-negative resection (R0) is challenging given the anatomic location of tumors and remains the most important prognostic indicator of long-term survival. The objective of this study is to review the impact of intraoperative revision of positive biliary margins in PHC on oncologic outcomes. Patients and Methods: Electronic databases were searched from inception to October 2021. Studies comparing three types of patients undergoing resection of PHC with intraoperative frozen section of the proximal and/or distal bile ducts were identified: those who were margin-negative (R0), those with an initially positive margin who had revised negative margins (R1R0), and those with a persistently positive margin with or without revision of a positive margin (R1). The primary outcome was overall survival (OS). Secondary outcomes included risk of postoperative complication. Results: A total of 449 studies were screened. Ten retrospective observational studies reporting on 1955 patients were included. Patients undergoing successful revision of a positive proximal and/or distal bile duct margin (R1R0) had similar OS to those with a primary margin-negative resection (R0) [hazard ratio (HR) 0.93, 95% confidence interval (CI) 0.72–1.19, p = 0.56, I² = 84%], and significantly better OS than patients with a positive final bile duct margin (R1) (HR 0.52, 95% CI 0.34–0.79, p = 0.002, I² = 0%). There was no increase in the risk of postoperative complications associated with additional resection, although postoperative morbidity was inconsistently reported. Conclusions: This review supports routine intraoperative biliary margin evaluation during resection of PHC with revision if technically feasible.