The Combination of Neutrophil-Lymphocyte Ratio and Platelet-Lymphocyte Ratio with Liquid Biopsy Biomarkers Improves Prognosis Prediction in Metastatic Pancreatic Cancer

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer with a highly inflammatory microenvironment and liquid biopsy has emerged as a promising tool for the noninvasive analysis of this tumor. In this study, plasma was obtained from 58 metastatic PDAC patients, and neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), circulating cell-free DNA (cfDNA) concentration, and circulating RAS mutation were determined. We found that NLR was significantly associated with both overall survival (OS) and progression-free survival. Remarkably, NLR was an independent risk factor for poor OS. Moreover, NLR and PLR positively correlated, and combination of both inflammatory markers significantly improved the prognostic stratification of metastatic PDAC patients. NLR also showed a positive correlation with cfDNA levels and RAS mutant allelic fraction (MAF). Besides, we found that neutrophil activation contributed to cfDNA content in the plasma of metastatic PDAC patients. Finally, a multi-parameter prognosis model was designed by combining NLR, PLR, cfDNA levels, RAS mutation, RAS MAF, and CA19-9, which performs as a promising tool to predict the prognosis of metastatic PDAC patients. In conclusion, our study supports the idea that the use of systemic inflammatory markers along with circulating tumor-specific markers may constitute a valuable tool for the clinical management of metastatic PDAC patients.

Keywords: NLR; PLR; RAS mutation; circulating tumor DNA; neutrophil elastase; pancreatic ductal adenocarcinoma.

Figure 1

Overall survival and progression-free survival rates according to the clinical characteristics of the patients. (A) Overall survival (OS) according to gender; (B) progression-free survival (PFS) according to gender; (C) OS according to EGOG; (D) PFS according to ECOG; (E) OS according to metastatic location; (F) PFS according to metastatic location.

Figure 2

Association between neutrophil–lymphocyte ratio and platelet–lymphocyte ratio with the clinical characteristics of the patients. (A) Neutrophil–lymphocyte ratio (NLR) and (B) platelet–lymphocyte ratio (PLR) in male or females patients, (C) NLR and (D) PLR in patients younger or older than 60 years, (E) NLR and (F) PLR according to the ECOG (* p < 0.05, ** p < 0.01).

Figure 3

Neutrophil–lymphocyte ratio and platelet–lymphocyte ratio in metastatic pancreatic ductal adenocarcinoma patients. (A) Neutrophil–lymphocyte ratio (NLR) in patients with liver metastasis or metastases elsewhere, (B) platelet–lymphocyte ratio (PLR) in patients with primary tumor located in the body-tail or the head of the pancreas, (C) overall survival (OS) according to NLR (cut-off: 5.52), (D) progression-free survival (PFS) according to NLR (cut-off: 5.52), (E) OS according to PLR (cut-off: 90.48), (F) PFS according to PLR (cut-off: 90.48) (* p < 0.05).

Figure 4

Association between neutrophil–lymphocyte ratio and platelet–lymphocyte ratio. (A) Correlation between neutrophil–lymphocyte ratio (NLR) and platelet–lymphocyte ratio (PLR) values; (B) overall survival (OS) according to the NLR and PLR combination (score 2 compared to score 0: p = 0.0004, score 2 compared to score 1: p = 0.0040); (C) progression-free survival (PFS) according to the NLR and PLR combination (score 2 compared to score 0: p = 0.0097; score 2 compared to score 1: p = 0.1463) (score 2, positive for both markers; score 1, positive for one of them; score 0: negative for both markers).

Figure 5

Association between neutrophil–lymphocyte ratio and cell-free DNA concentration. (A) Correlation between neutrophil–lymphocyte ratio (NLR) values and circulating cell-free DNA (cfDNA) levels; (B) overall survival (OS) according to the NLR and cfDNA combination (score 2 compared to score 0: p = 0.0001, score 2 compared to score 1: p = 0.0008); (C) progression-free survival (PFS) according to the NLR and cfDNA combination (score 2 compared to score 0: p = 0.0037; score 2 compared to score 1: p = 0.0119) (score 2, positive for both markers; score 1, positive for one of them; score 0: negative for both markers).

Figure 6

Circulating levels of neutrophil elastase in metastatic pancreatic ductal adenocarcinoma patients. (A) Correlation between plasma levels of neutrophil elastase and neutrophil–lymphocyte ratio (NLR); (B) correlation between plasma levels of neutrophil elastase and cell-free DNA (cfDNA); (C) correlation between plasma levels of neutrophil elastase and CA19-9; (D) plasma levels of neutrophil elastase in pancreatic ductal adenocarcinoma patients with metastatic lesions in the liver or elsewhere; (E) overall survival (OS) according to circulating levels of neutrophil elastase (cut-off: 23.15 ng/mL); (F) progression-free survival (PFS) according to circulating levels of neutrophil elastase (cut-off: 23.15 ng/mL) (* p < 0.05).

Figure 7

Association between neutrophil–lymphocyte ratio and plasma RAS mutation. (A) Neutrophil–lymphocyte ratio (NLR) according to RAS mutational status in plasma; (B) correlation between NLR values and RAS mutant allelic fraction (MAF) in plasma; (C) overall survival (OS) according to the NLR and RAS mutational status combination (score 2 compared to score 0: p < 0.0001; score 2 compared to score 1: p = 0.0003); (D) progression-free survival (PFS) according to the NLR and RAS mutational status combination (score 2 compared to score 0: p = 0.0003; score 2 compared to score 1: p = 0.0533); (E) OS according to the NLR and MAF combination (score 2 compared to score 0: p = 0.0029; score 2 compared to score 1: p = 0.0037); (F) PFS according to the NLR and MAF combination (score 2 compared to score 0: p = 0.0420; score 2 compared to score 1: p = 0.3008) (score 2, positive for both markers; score 1, positive for one of them; score 0, negative for both markers) (** p < 0.01).

Figure 8

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).