Prediction of Isolated Local Recurrence After Resection of Pancreatic Ductal Adenocarcinoma: A Nationwide Study

Abstract

Abstract Background Distinguishing postoperative fibrosis from isolated local recurrence (ILR) after resection of pancreatic ductal adenocarcinoma (PDAC) is challenging. A prognostic model that helps to identify patients at risk of ILR can assist clinicians when evaluating patients’ postoperative imaging. This nationwide study aimed to develop a clinically applicable prognostic model for ILR after PDAC resection. Patients and Methods An observational cohort study was performed, including all patients who underwent PDAC resection in the Netherlands (2014–2019; NCT04605237). On the basis of recurrence location (ILR, systemic, or both), multivariable cause-specific Cox-proportional hazard analysis was conducted to identify predictors for ILR and presented as hazard ratios (HRs) with 95% confidence intervals (CIs). A predictive model was developed using Akaike’s Information Criterion, and bootstrapped discrimination and calibration indices were assessed. Results Among 1194/1693 patients (71%) with recurrence, 252 patients (21%) developed ILR. Independent predictors for ILR were resectability status (borderline versus resectable, HR 1.42; 95% CI 1.03–1.96; P = 0.03, and locally advanced versus resectable, HR 1.11; 95% CI 0.68–1.82; P = 0.66), tumor location (head versus body/tail, HR 1.50; 95% CI 1.00–2.25; P = 0.05), vascular resection (HR 1.86; 95% CI 1.41–2.45; P < 0.001), perineural invasion (HR 1.47; 95% CI 1.01–2.13; P = 0.02), number of positive lymph nodes (HR 1.04; 95% CI 1.01–1.08; P = 0.02), and resection margin status (R1 < 1 mm versus R0 ≥ 1 mm, HR 1.64; 95% CI 1.25–2.14; P < 0.001). Moderate performance (concordance index 0.66) with adequate calibration (slope 0.99) was achieved. Conclusions This nationwide study identified factors predictive of ILR after PDAC resection. Our prognostic model, available through www.pancreascalculator.com, can be utilized to identify patients with a higher a priori risk of developing ILR, providing important information in patient evaluation and prognostication.