Peripheral Blood Cell Variables Related to Systemic Inflammation in Patients With Unresectable or Metastatic Pancreatic Cancer: A Systematic Review and Meta-Analysis.

ABSTRACT: Systemic inflammatory response (SIR) plays a central role in the prognosis of unresectable or metastatic pancreatic ductal adenocarcinoma (mPDAC), and many SIR-related peripheral blood cell (PBC)-derived variables have been proposed as prognostic factors. The study aims to perform a systematic review and, for the more studied PBC-derived variables, a meta-analysis. A systematic review from 2000 to 2020 on 2 databases by predefined criteria was performed for PBC-derived variables in patients with mPDAC receiving chemotherapy in relation with overall survival. Eligible studies were selected by inclusion criteria, and only the PBC variables reported in at least 10 studies were evaluated by meta-analysis. Three hundred and eighty articles were found, and 28 studies were selected. Neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) were reported in 28 and 10 articles, respectively. The subsequent meta-analyses supported the prognostic effect for both, NLR (hazard ratio, 2.10; 95% confidence interval, 1.87-2.37) and PLR (hazard ratio, 1.22; 95% confidence interval, 1.08-1.37). Heterogeneity was significant for NLR (I2 = 62%) and low for PLR (I2 = 24%). Among SIR-related PBC-derived variables, NLR is the most suitable prognostic factor for future clinical trials of patients with mPDAC.