Role of Intraoperative Frozen Section Assessment of Proximal Bile Duct Margins and the Impact of Additional Re-Resection in Perihilar Cholangiocarcinomas.

Intraoperative frozen section (FS) analysis to assess the bile duct margin status is commonly used to assess the completeness of resection during surgery for perihilar cholangiocarcinoma (pCCA) resection. However, the impact of additional re-section on the long-term outcome after obtaining an initial positive margin remains unclear. Patients diagnosed as pCCA on preoperative imaging and subjected to curative intent surgery from May 2013 to June 2021 with a minimum follow-up of 2 years were included. Intraoperative FS analysis of the proximal bile duct margin was performed in all patients. A positive margin was defined by the presence of invasive cancer. Out of the 62 patients with a preoperative diagnosis of pCCA on imaging, 35 patients were included for final analyses after excluding patients with inoperable disease (on staging laparoscopy or local exploration) and other/benign pathology on the final histopathology report. Out of the 35 patients, patients with postoperative 90-day mortality were excluded from the final survival analysis. FS analysis revealed an initial positive margin in 10 (28.5%) patients. Among 10 patients who underwent re-resection to achieve negative proximal margins, only 5 patients achieved a negative margin (secondary R0). An initial positive margin was associated with poor long-term outcomes. Median disease-free survival (DFS) and overall survival (OS) were 16 and 19.6 months for patients with an initial positive margin, but 36 and 58.2 months for patients with an initial negative margin, respectively ( p  = 0.012). The median DFS and OS were significantly lower for those with secondary R0 as compared to primary R0 (16 vs. 36 months for DFS, p  = 0.117 and 19.6 vs. 58.2 months for OS, p  = 0.027, respectively). An intraoperative FS positive proximal hepatic duct margin dictates poor long-term outcomes for patients with resectable pCCA. Additional resection has a questionable benefit on survival, when a secondary negative margin is achieved.