R Status is a Relevant Prognostic Factor for Recurrence and Survival After Pancreatic Head Resection for Ductal Adenocarcinoma

Background: The prognostic role of resection margins in pancreatic ductal adenocarcinoma (PDAC) is debated. This study aimed to investigate the impact that global and individual resection margin status after pancreatic head resection for PDAC has on disease-free survival (DFS) and disease-specific survival (DSS). Methods: Surgical specimens of pancreaticoduodenectomy/total pancreatectomy performed for PDAC were examined with a standardized protocol. Surgical margin status (biliary, pancreatic neck, duodenal, anterior and posterior pancreatic, superior mesenteric vein groove and superior mesenteric artery margins) was classified as the presence of malignant cells (1) directly at the inked surface (R1 direct), (2) within less than 1 mm (R1 ≤ 1 mm), or (3) with a distance greater than 1 mm (R0). Patients with a positive neck margin at the final histology were excluded from the study. Results: Of the 362 patients included in the study, 179 patients (49.4 %) had an R0 resection, 123 patients (34 %) had an R1 ≤ 1 mm resection, and 60 patients (16.6 %) had an R1 direct resection. The independent predictors of DFS were R1 direct resection (hazard ratio [HR], 1.49), R1 ≤ 1 mm resection (HR, 1.38), involvement of one margin (HR, 1.36), and involvement of two margins or more (HR, 1.55). When surgical margins were analyzed separately, only R1 ≤ 1 mm superior mesenteric vein margin (HR, 1.58) and R1 direct posterior margin (HR, 1.69) were independently associated with DFS. Conclusions: Positive R status is an independent predictor of DFS (R1 direct and R1 ≤ 1 mm definitions) and of DSS (R1 direct). The presence of multiple positive margins is a risk factor for cancer recurrence and poor survival. Different surgical margins could have different prognostic roles.