Estimating Recurrence after Upfront Surgery in Patients with Resectable Pancreatic Ductal Adenocarcinoma by Using Pancreatic CT: Development and Validation of a Risk Score

Background: No preoperative model is available for predicting postsurgical prognosis of patients with resectable pancreatic ducral adenocarcinoma (PDAC). Purpose: To develop and validate a preoperative risk scoring system using clinical and CT variables to predict recurrence-free survival (RFS) after upfront surgery in patients with resectable PDAC. Materials and Methods: In this retrospective study, consecutive patients with resectable PDAC underwent upfront surgery from January 2014 to December 2015 (development set) and from January 2016 to January 2017 (test set). In the development set, multivariable Cox proportional hazard modeling with bootstrapping was used to select clinical and CT variables associated with RFS and to construct a risk scoring system. The discrimination capability of the risk score was assessed by using the Harrell C-index and compared with that of pathologic American Joint Committee on Cancer tumor stage. The risk score was validated in the test set. Results: A total of 395 patients were evaluated, including 262 patients (mean age +/- standard deviation, 64 years +/- 10; 155 men)in the development set and 133 (mean age, 64 years +/- 9; 79 men) in the test set. Five independent variables predicted risk of recurrenceor death: tumor size (hazard ratio [HR], 1.23; 95% confidence interval [CI]: 1.05, 1.44; P =.009), hypodense tumor in the portal venous phase (HR, 1.66; 95% CI: 1.01, 2.73; P =.04), tumor necrosis (HR, 2.04; 95% CI: 1.38, 3.03; P<.001), peripancreatic tumor infiltration (HR, 1.50; 95% CI: 1.07, 2.11; P =.02), and suspicious metastatic lymph nodes (HR, 1.94; 95% CI: 1.38, 2.72; P<.001). In the test set, the risk score showed good discrimination capability (C-index of 0.68; 95% CI: 0.63, 0.74) and outperformed the pathologic tumor stage (C-index of 0.60; 95% CI: 0.55, 0.66; P =.03). Patients were categorized into favorable, intermediate, and poor prognosis groups with 1-year RFS of 0.87, 0.58, and 0.26, respectively. Conclusion: The presented preoperative risk score can predict recurrence-free survival after upfront surgery in patients with resectable pancreatic ductal adenocarcinoma. (C) RSNA, 2020