Liver Margin Status in pCCA : Ann Surg | May 2026

Introduction

Achieving margin-negative resection remains one of the major determinants of long-term outcomes in perihilar cholangiocarcinoma (pCCA). While proximal and distal ductal margins are routinely evaluated, the liver margin (LM) represents the largest and least standardized resection margin in pCCA surgery. This multicenter study investigated the prevalence, spatial distribution and prognostic significance of LM positivity using serial whole-mount digital large-section (WDLS) pathology.

Problem Statement

Among 227 patients undergoing major hepatectomy for pCCA, WDLS-based assessment identified LM R1 resection in 38.6% of cases, substantially higher than conventional small-section analysis alone. Standard pathology underestimated positive LM involvement, detecting only approximately 6% of R1 cases. Importantly, patients classified as true R0 by WDLS demonstrated superior overall survival and recurrence-free survival compared with conventionally assessed controls. Spatial mapping revealed that 95% of carcinoma involvement occurred within 20 mm of the proximal ductal margin (P-DM), and a P-DM distance <5 mm independently predicted LM positivity.

Summary

This study establishes liver margin positivity as a major contributor to occult R1 resection in pCCA and demonstrates that conventional sampling substantially underestimates residual microscopic disease. WDLS significantly improved diagnostic accuracy and refined pathological risk stratification. The authors propose a practical LM assessment strategy focused on systematic examination within a 20 mm radius surrounding the proximal ductal margin, particularly in patients with a P-DM distance <5 mm. These findings may redefine pathological evaluation standards in pCCA and improve surgical quality assessment, prognostication and postoperative management.