Main pancreatic duct to parenchymal thickness ratio and degree of atrophy are associated with overall survival in primarily resected pancreatic cancer

Abstract

Background: Ductal adenocarcinoma of the pancreatic head induces morphological changes of the gland structure, with potential parenchymal degeneration and main pancreatic duct (MPD) dilation. Aim of this study was to evaluate whether these radiologic findings are associated with oncologic outcomes. Material & Methods: From an institutional prospectively maintained database, patients who underwent upfront pancreatoduodenectomy and had a preoperative CT-scan imaging available were assessed. Included patients were divided into short- (3-12 months following surgery) and long-term (≥36 months) survivors. Thickness of the pancreatic gland, parenchymal atrophy, size of the MPD, and distance of the tumor from the ampulla were assessed at the preoperative CT-scan. Results: One-hundred-eighteen patients were included, 68 (57.6%) in the short- and 50 (42.4%) in the long-term survival group. Patients in the short-term survival group had significantly higher Ca19-9 levels (p=0.027), larger tumors (32.6±12.1mm vs. 26.5±11.6mm, p=0.008), poorer differentiation (p=0.003), higher positive R-status rate (p=0.008), and reduced receipt of adjuvant chemotherapy (p=0.020). A significant difference in parenchymal atrophy between groups was also detected (p=0.032). Moreover, the MPD-to-pancreatic thickness ratio normalized for the distance from the ampulla was significantly lower in the short-term group (3.6±6.2 vs. 8.2±12.0mm, p=0.016). At survival analysis, the MPD-to-pancreatic thickness ratio and the degree of parenchymal atrophy were associated with OS (p=0.01 and p=0.020, respectively; log-rank test). At a multivariate Cox-proportional hazards regression model, only the MPD-to-pancreatic thickness ratio, dichotomized at the best predictive value, was independently associated with OS (HR=0.48; p=0.015), together with positive R-status (HR=1.78; p=0.040), and receipt of adjuvant treatment (HR=0.48; p=0.015). Conclusions: A high MPD-to-pancreatic thickness ratio normalized for the distance from the ampulla predicts improved long-term survival in patients undergoing upfront resection for cancer of the pancreatic head. Whether these radiologic features are related to different biological tumor behavior remains elusive and should be addressed in further studies.