Lymph Node Ratio, Perineural Invasion and R1 Resection as Independent Prognostic Factors in Pancreatic Adenocarcinoma: A Retrospective Cohort Study.

INTRODUCTION: The prognosis of pancreatic ductal adenocarcinoma has been associated with several factors. The aim of the present study was to correlate tumor-related factors and pathological findings with disease-free survival (DFS) and overall survival (OS) in patients undergoing pancreaticoduodenectomy. MATERIAL AND METHODS: From a prospectively maintained database, we reviewed 89 pancreatic ductal adenocarcinomas in patients who underwent pancreaticoduodenectomy from 2010 to 2014. The impact of histopathologic or tumor-related data, including a lymph node ratio greater than 15% (LNR15), on survival was analyzed. RESULTS: Univariate analysis of DFS and OS showed that vascular resection, pT, pN, LNR15, microvascular, lymphatic, and perineural invasion, and R1 resection influenced survival. Only LNR15, perineural invasion and R1 resection were independent predictors for both DFS (HR 6.39, p = 0.011; HR 8.53, p = 0.003; HR 9.68, p = 0.002, respectively) and OS (HR 4.21, p = 0.039; HR 5.41, p = 0.020; HR 4.41, p = 0.036, respectively). CONCLUSIONS: This study demonstrates that LNR15, perineural invasion and R1 resection are independently associated with DFS and OS.