Preoperative Neutrophil-to-lymphocyte Ratio Predicts Tumor-infiltrating CD8+ T Cells in Biliary Tract Cancer.

Objective: This study evaluated the prognostic significance of preoperative neutrophil-to-lymphocyte ratio (NLR) and CD8+ tumor-infiltrating lymphocytes (TILs), and whether preoperative NLR was associated with CD8+ TILs in biliary tract cancers (BTCs).

Methods: A total of 154 patients with BTCs who underwent surgery were enrolled in this study. We obtained neutrophil and lymphocyte counts, and calculated NLR from preoperative peripheral blood samples. CD8+ TILs were identified by immunohistochemical staining.

Results: The overall survival (OS) and recurrence-free survival (RFS) of patients with high NLR were shorter than those with low NLR. The OS and RFS of patients with high CD8+ TILs were longer than those with low CD8+ TILs. Preoperative NLR and CD8+ TILs were negatively correlated.

Conclusions: NLR and CD8+ TILs were associated with OS and RFS in BTCs. NLR can predict CD8+ TILs infiltrating the cancer microenvironment.