Association between the preoperative neutrophil-to-lymphocyte ratio and tertiary lymphoid structures surrounding tumor in gastric cancer.

The neutrophil-to-lymphocyte ratio (NLR) has been reported to be associated with a poor prognosis in various types of cancer. We previously reported that an antitumor immune response was induced by tertiary lymphoid structures (TLSs) surrounding tumor, and increased TLS was an independent prognostic factor in patients with gastric cancer. The present study examined the stratification based on the correlation between the preoperative NLR and TLS density in gastric cancer. A total of 199 patients who underwent surgery for stage Ib-IV gastric cancer were included in the study. Receiver operating characteristic curve analysis was used to determine the appropriate cut-off values of the preoperative NLR and the TLS density. The prognostic factors were evaluated in a multivariate analysis. The median NLR was 2.18 (mean ± SD, 2.7±2.04). A total of 91 patients with an NLR ≥2.33 was classified into the high NLR group. The overall survival was significantly improved in patients with a low NLR than in those with a high NLR. Additionally, the low NLR group tended to have a high TLS density. The multivariate analysis indicated that the preoperative NLR and TLS density were independent risk factors. When the patients were classified into the high and low NLR and TLS groups and the survival rates were compared, the prognosis was significantly improved in the low NLR and high TLS group than in the other groups. The preoperative NLR may be associated with the presence of TLSs surrounding the tumor, and the combination of NLR and TLS may be useful for the stratification of patient prognosis. The present results suggested that the NLR and TLS density may be surrogate markers for immunotherapy against gastric cancer.