Systemic inflammatory responses have important roles in the development and progression of cancer, including the propensity for metastasis. A high neutrophil-to-lymphocyte ratio (NLR) is associated with poor prognosis in nasopharyngeal carcinoma (NPC), but the underlying mechanisms are not clear. Vascular endothelial growth factor (VEGF) has been reported to be involved in the recruitment of pro-angiogenic neutrophils in tumor metastasis progress. Therefore, we focused on the correlations among NLR, neutrophil count, and VEGF during metastasis and explored the reasons for changes of NLR in advanced NPC.
Consecutive patients who had been investigated with magnetic resonance imaging and irradiated with intensity-modulated radiotherapy(IMRT) from November 2011 to December 2012 were studied retrospectively. Clinical parameters (NLR, neutrophil count) were measured and their association with NPC stage advancement and VEGF were assessed using the Kruskal–Wallis test. Associations with patient survival were analyzed using the Kaplan–Meier method and log-rank test.
NLR was elevated in advanced N stage (P < 0.0001) and M stage disease (P = 0.0034), but not T stage disease (P = 0.7049). Changes to the NLR in advanced N stage and M stage disease were affected most strongly by neutrophil count (P = 0.0074 and P = 0.0064, respectively) and higher NLR levels were associated with higher neutrophil count (P < 0.0001). NLR > 2.26 and positive VEGF expression (+++) correlated significantly with distant metastasis-free survival (P = 0.0340 and P = 0.0023, respectively). Neutrophil counts correlated positively with VEGF expression (P = 0.0024) in NPC tissue.
Our results demonstrate a positive correlation between NLR, neutrophil count, and VEGF expression in NPC. Higher NLR and VEGF expression are associated with distant metastasis-free survival among patients with NPC, which implies that they set a basis of immune activation in advanced nasopharyngeal carcinoma.