Preoperative radiotherapy improves overall survival of pT4 pancreatic ductal adenocarcinoma patients after surgical resection.

Abstract

The aim of delivering radiotherapy for pancreatic ductal adenocarcinoma patients was to sterilize vessel margin, increase R0 resection rate and delay local progression. Whether preoperative radiotherapy could prolong overall survival of surgical candidates remained unknown. Pancreatic ductal adenocarcinoma patients receiving radical resection from surveillance, epidemiology and end result database were enrolled. Propensity score matching was conducted to balance difference in baseline characteristics, and survival analyses were performed to compare overall survival between preoperative radiotherapy and upfront resection groups. Cox proportional hazard regression model and subgroup analyses were utilized to identify prognostic factors. A total of 11665 and 597 pancreatic ductal adenocarcinoma patients receiving upfront resection and preoperative radiotherapy followed by resection from 2004 to 2016 were identified, respectively, while baseline characteristics were distinct between groups. After propensity score matching, preoperative radiotherapy was not associated with better overall survival (upfront resection vs preoperative radiotherapy, 26 vs 27months). Subgroup analyses showed that preoperative radiotherapy was a protective factor in pT4 (hazard ratio=0.64, 95% confidence interval: 0.47-0.88) but a negative predictor in pT1 (hazard ratio=1.79, 95% confidence interval: 1.08-2.97) patient populations. Survival analyses showed that preoperative radiotherapy improved overall survival of patients with pT4 stage (upfront resection vs preoperative radiotherapy, 19 vs 25months) and involvement of celiac axis, superior mesenteric artery and aorta (upfront resection vs preoperative radiotherapy, 20 vs 27months), while preoperative radiotherapy was associated with worse overall survival in patients with pT1 tumor (upfront resection vs preoperative radiotherapy, 39 vs 24months). Preoperative radiotherapy could improve survival of resected pancreatic ductal adenocarcinoma patients with pT4 stage or with celiac axis, superior mesenteric artery and aorta invasion.