Preoperative Score to Stratify Recurrence Risk After Curative Resection of Resectable Pancreatic Ductal Adenocarcinoma: A Retrospective Cohort Study

Abstract Background: Oncological survival after operation of resectable pancreatic ductal adenocarcinoma (R-PDAC) is variable depending on various factors. Preoperative risk stratification could guide decision-making in multidisciplinary treatment concepts. We develop and validate a prognostic score for disease-free survival (DFS) in R-PDAC to solve this issue.Methods: 421 R-PDAC patients between January 2012 and December 2015 were enrolled. Performance of the final model was evaluated with respect to discrimination, calibration and clinical usefulness. A prognostic score based on the final model was developed, and external validated in 290 patients.Results: On multivariable analysis, age, tumor size, carbohydrate antigen (CA)19-9, CA125, lymphocyte-monocyte ratio, and systemic-immune-inflammation index were independently associated with DFS. Final model had acceptable calibration, discrimination and internal validity. The prognostic score could delineate low- and high-risk groups with median DFS of 19.6 and 10.1 months (P<0.0001). Tumors in high-risk group exhibited more aggressive pathobiological behaviors. Additionally, at 1-year follow-up, the restricted mean survival time was longer with adjuvant chemotherapy than those without in low-risk patients. However, no significant difference was detected in high-risk patients.Discussion: The prognostic score could accurately predict DFS preoperatively in R-PDAC patients and provide reference for risk-adapted strategies formulation for R-PDAC management in the future.