Proposing an Imaging-based Morphological Assessment of Pancreatic Ductal Adenocarcinoma as a Predictor of R1 Resection

Abstract

Introduction: Pancreatic ductal adenocarcinoma (PDAC) can be clinically under-staged on preoperative cross-sectional imaging which may affect intraoperative resectability. The purpose of this study is to define imaging-based morphologic criteria for PDAC in tumors deemed resectable at presentation and assess their correlation with R1 resection. Methods: A retrospective chart review of 54 consecutive pancreatoduodenectomies performed for PDAC between 2016- 2018 was performed. Sectional computed Tomography (CT) images were reviewed by two senior radiologists who labeled tumors as “mass-forming” or “infiltrative” morphology. These classifications were then correlated with resection margin status. Significance was defined as a p value <0.1. Results: Of the 54 patients included in the study, 28 and 26 were classified as mass forming and infiltrative based on radiological review, respectively. There was no significant difference in pathological T and N staging (p=0.63 and p=0.62, respectively). Infiltrative tumors demonstrated smaller sizes on preoperative images (average: 3.3 versus 4 cm, p=0.02). Although no difference was appreciated between both morphologies regarding portal vein and superior mesenteric artery margins (p=0.64 and p=0.81, respectively), infiltrative tumors were found to be associated with more positive bile duct and pancreatic margins (p=0.06 and p=0.07, respectively). Conclusion: We propose a new imaging-based definition of PDAC into “mass-forming” and “infiltrative” morphologies. Understanding the higher rate of R1 resection in infiltrative tumors would improve selection process of patients with PDAC to neoadjuvant therapy prior to definitive resection.Tabled 1Radiological featureMass-formingInfiltrativeBorderPresence of a well-defined interfaceAbsence of a well-defined interfaceMassVisible and clearly identifiableInferred in the absence of a clear mass and presence of pancreatic and/or common bile ductal dilationp Open table in a new tab