Prognostic Factors Associated with Long-Term Recurrence-Free Survival after Resection of Pancreatic Ductal Adenocarcinoma (PDAC): A Nationwide Analysis

Abstract

Introduction: About 80% of patients undergoing PDAC resection develop disease recurrence within two years after surgery, contributing to poor survival rates. However, 20% of patients do have long-term recurrence-free survival (RFS). In this study, we aimed to identify prognostic factors associated with an RFS of 2-3 years, 3-5 years or >5 years after PDAC resection. Method: This national cohort study includes all patients who underwent PDAC resection in the Netherlands between 2014-2016. Data was collected prospectively from the Dutch Pancreatic Cancer Audit and retrospectively from the patients’ records. Patients were divided into four groups based on RFS: <2 years (reference group), 2-3 years, 3-5 years and >5 years. Prognostic factors were determined by multinomial regression analysis. Results: A total of 836 patients with a median follow-up of 46 (interquartile range (IQR) 34-58) months and median survival of 20 (IQR 11-36) months were analyzed. Information on RFS was available in 627 patients: 485 patients (77%) had an RFS of <2 years, 75 patients (15%) of 2-3 years, 33 patients (5%) of 3-5 years and 34 patients (5%) of >5 years. Further results are shown in Table 1. Conclusions: A well/moderately differentiated tumor and R0 (≥1 mm) resection margin status are related to an RFS of 3-5 years. Fewer positive lymph nodes are associated with an RFS of 3-5 and >5 years. These prognostic factors can be useful in estimating the long-term prognosis for patients and contribute to individualized follow-up and treatment strategies.Tabled 1FP19-4Table 1. Results of 627 patients who underwent PDAC resection between 2014 and 2016 (excluding patients with irradical resection or complication-related mortality within 90 days postoperatively)Recurrence-free survival*2-3 years1. years> 5 yearsOR**95% CIP-valueOR**95% CIP-valueOR**95% CIP-valueDifferentiation (well/moderate vs. poor/undifferentiated)1.780.98-3.220.0572.821.09-7.340.0331.090.48-2.480.830Number of positive lymph nodes (continuous)1.030.94-1.130.4941.321.08-1.610.0061.571.20-2.05<0.001Resection margin status (R0 ≥ 1 mm vs. R1 < 1 mm)1.200.70-2.060.5083.431.45-8.090.0051.630.74-3.630.228Adjuvant chemotherapy (yes vs. no)2.991.56-5.72<0.0012.450.99-6.050.0521.350.57-3.170.498PDAC: pancreatic ductal adenocarcinoma; OR: odds ratio; CI: confidence interval. * Compared to the reference group with a recurrence-free survival of <2 years. ** Multinomial regression analysis corrected for gender, CACI-score, neoadjuvant therapy, preoperative CA 19-9 value, tumor location, vascular resection, diameter of the tumor, tumor differentiation, lymphovascular invasion, neural invasion, number of positive lymph nodes, resection margin status, major complications, and adjuvant chemotherapy. In case of a continuous variable, 1 unit decrease of the relevant variable is related to the corresponding odds ratio. Open table in a new tab PDAC: pancreatic ductal adenocarcinoma; OR: odds ratio; CI: confidence interval. * Compared to the reference group with a recurrence-free survival of <2 years. ** Multinomial regression analysis corrected for gender, CACI-score, neoadjuvant therapy, preoperative CA 19-9 value, tumor location, vascular resection, diameter of the tumor, tumor differentiation, lymphovascular invasion, neural invasion, number of positive lymph nodes, resection margin status, major complications, and adjuvant chemotherapy. In case of a continuous variable, 1 unit decrease of the relevant variable is related to the corresponding odds ratio.