Background: The neutrophil-to-lymphocyte ratio (NLR) has been reported to be both a prognostic biomarker for cancer and associated with inflammation, but its predictive role in tumor immunity is not clear. The present study examined the correlations of the NLR and immune suppression with the prognoses in patients with esophageal squamous cell carcinoma (ESCC).
Methods: We performed a retrospective review of 1168 patients who were newly diagnosed with stage T1N(+) and T2-T4 ESCC at our hospital. The NLR of each ESCC patient prior to treatment was calculated, and the associations of the NLR with various clinicopathological parameters and prognoses were then examined. In addition, correlations of the proportion of myeloid-derived suppressor cells (MDSCs) and level of interleukin (IL)-6 with the NLR were assessed in 242 ESCC patients.
Results: An elevated NLR was significantly correlated with advanced-stage disease and reduced overall survival (OS) of ESCC patients. Furthermore, the levels of IL-6 in tumors and MDSCs in the peripheral circulation were significantly correlated with the prognoses of ESCC, and the NLR was positively correlated with MDSC levels in the circulation and IL-6 staining intensity in tumor specimens. Moreover, a high NLR was significantly associated with reduced OS in the 926 patients treated with concomitant chemoradiotherapy, but not in the 242 patients who underwent surgical intervention.
Conclusion: The NLR may represent a clinically useful biomarker to guide ESCC treatment decisions. Patients with a higher NLR may be an optimal subgroup for IL-6- and MDSC-targeted therapy.