Multiple blood-based biomarkers for the prognosis of metastatic pancreatic ductal adenocarcinoma patients. (A) Overall survival (OS) according to neutrophil–lymphocyte ratio (NLR) and CA19-9 combination (score 2 compared to score 0: p < 0.0001; score 2 compared to score 1: p = 0.0226); (B) progression-free survival (PFS) according to NLR and CA19-9 combination (score 2 compared to score 0: p = 0.0016; score 2 compared to score 1: p = 0.0021) (score 2, positive for both markers; score 1, positive for one of them; score 0, negative for both markers); (C) OS according to the combination of multiple blood-based biomarkers (NLR, platelet–lymphocyte ratio (PLR), cell-free DNA (cfDNA) concentration, RAS status, RAS mutant allelic fraction (MAF) and CA19-9) (score 2 compared to score 0: p < 0.0001; score 2 compared to score 1: p = 0.0026); (D) PFS according to the combination of multiple blood-based biomarkers (NLR, PLR, cfDNA concentration, RAS status, RAS MAF, and CA19-9) (score 2 compared to score 0: p = 0.0008; score 2 compared to score 1: p = 0.0086) (score 2, positive for all markers; score 1, positive for 3, 4 or 5 markers; score 0, positive for 1 or 2 markers or negative for all of them).