Post-adjuvant chemotherapy CA19-9 levels predict prognosis in patients with pancreatic ductal adenocarcinoma: A retrospective cohort study

Background: Carbohydrate antigen 19-9 (CA19-9) is a widely used tumor marker for pancreatic ductal adenocarcinoma (PDAC). In addition, several studies have reported the utility of both pre- and postoperative CA19-9 levels as prognostic factors in resectable PDAC. However, little is known about the implications of post-adjuvant chemotherapy (AC) CA19-9 levels. The purpose of this study was to examine the utility of the post-AC CA19-9 level as a prognostic marker for relapse-free survival (RFS) in resectable PDAC. Methods: A total of 119 patients who completed AC were analyzed (normal post-AC CA19-9, n = 79; high post-AC CA19-9, n = 40). The upper limit of the normal (ULN) serum level of CA19-9 was 37 U/mL. Results: Median RFS was significantly shorter for patients with high post-AC CA19-9 levels than for those with normal post-AC CA19-9 (10.4 months vs. 29.6 months, respectively; p < 0.001). After adjustment, high post-AC CA19-9 level was an independent predictive factor for short RFS (hazard ratio for RFS, 2.72). Median overall survival was significantly shorter in patients with high post-AC CA19-9 levels than in those with normal postoperative CA19-9 levels (24.7 months vs. 92.1 months, respectively; p < 0.001). The optimal cutoff value of post-AC CA19-9 levels for prediction of early recurrence was >1.5 x UNL (55.5 U/mL), with a 74.2% positive predictive value. Conclusions: The present results show that high post-AC CA19-9 level is an independent prognostic factor for short RFS in patients with resected PDAC. In addition, it may be useful for predicting early recurrence. (C) 2016 IAP and EPC. Published by Elsevier B.V. All rights reserved.