Radial and Longitudinal Margins in Surgery of Perihilar Cholangiocarcinoma: When R1 Definition Is Associated with Different Prognosis

Abstract

Background: The purpose of study is to evaluate the impact of positive margins on long-term outcome of patients affected by perihilar cholangiocarcinoma (PHC) depending on the pattern of neoplastic infiltration (radial versus longitudinal) and to analyze predictive factors for survival specifically in the population of R1. Methods: Data regarding histopathological data were prospectively collected in patients submitted to surgery for PHC between 2004 and 2019 at San Raffaele Hospital, Milano. The outcome of patients with R1 (88 out of 264, 33.3% of the whole series) and R0 margins was compared. Within R1 group, the long term outcome was compared between patients with radial only infiltration (n=31), longitudinal only infiltration (n=30) and radial+longitudinal infiltration (n=27). Results: 3 years and 5 years long term survival was significantly different between the R0 (55% and 42% respectively) and the R1 group (42% and 18% respectively) with p<0.05. Within R1 group, patients with radial only and radial + longitudinal infiltration had a worse long term outcome compared with patients with longitudinal only infiltration(median DFS was 18 and 23 months respectively, p<0.05, while median OS was 33 and 39 months respectively, p<0.05). Together with R1 margin status, factors associated with long term outcome at multivariate analysis were nodal status, side of hepatectomy, grading and radial margin infiltration. Conclusion: Infiltration of radial resection margins in PHC is associated with a worse prognosis among patients with R1 margins and should be specifically taken into consideration to determine the indication for adjuvant treatments.