INTRODUCTION: To clarify the prognostic significance of the C-reactive protein to prealbumin ratio (CRP or PALB) in patients with pancreatic cancer after radical resection. METHODS: A total of 432 patients with pathologically confirmed pancreatic ductal adenocarcinoma were enrolled in this retrospective study. The predictive capacity of various inflammatory indices was analyzed and compared using the area under the time-dependent receiver operating characteristic curve, including CRP or PALB, CRP-to-albumin ratio, neutrophil-to-lymphocyte ratio, and platelet-to-lymphocyte ratio. The univariate and multivariate Cox hazard models were employed to analyze the effects of CRP or PALB on overall survival (OS) and recurrence-free survival (RFS). RESULTS: The optimal cut-off value for preoperative CRP or PALB was 5.94, which was derived from the receiver operating characteristic curve. In comparison with traditional inflammatory indices, CRP or PALB had the highest area under the time-dependent receiver operating characteristic curve (0.693 for 3-y OS, 0.664 for 3-y RFS, 0.662 for 5-y OS, and 0.670 for 5-y RFS), all with P <
0.05. However, when compared with neutrophil-to-lymphocyte ratio, the predictive power of CRP or PALB was not significant for 3-y RFS (P = 0.085). Based on the results of the univariate and multivariate survival analyses, patients in the high CRP or PALB group (HCP: CRP or PALB >
5.94) exhibited significantly poorer OS and RFS (median OS: 20.0 versus. 38.0 mo, P = 0.003
median RFS: 10.0 versus. 22.0 mo, P <
0.001) than those in the low CRP or PALB group (CRP or PALB ≤5.94). The multivariate analysis indicated that the HCP was independently associated with poor OS (hazard ratio (HR): 1.556, 95% confidence interval (CI) [1.089-2.222], P = 0.015) and RFS (HR: 1.551, 95% CI [1.135-2.119], P = 0.006). CONCLUSIONS: The predictive capacity of preoperative CRP or PALB in pancreatic ductal adenocarcinoma patients exceeds that of traditional inflammatory indices. HCP levels are significantly correlated with a poor prognosis.