In Patients with Colorectal Cancer, Preoperative Serum Interleukin-6 Level and Granulocyte/Lymphocyte Ratio Are Clinically Relevant Biomarkers of Long-Term Cancer Progression

Objective: To investigate the clinical significance of the serum inflammatory cytokines and the blood granulocytes/lymphocytes (G/L) ratio in patients with colorectal cancer. Methods: Forty-six patients underwent surgery for colorectal cancer. The G/L ratio and serum inflammatory cytokines including interleukin (IL)-1β, IL-6, IL-8, tumour necrosis factor-α (TNF-α), granulocyte colony-stimulating factor and macrophage colony-stimulating factor (M-CSF) were measured before surgery and correlated with the Tumour Node Metastasis classification and overall survival. Results: Serum IL-6 in T3-4, N1-2, M1 cases and cancer stages III-IV sub-groups was significantly higher than in Tis-2, N0, M0 and cancer stages 0-II sub-groups. The G/L ratio, serum M-CSF and TNF-α in T3-4 cases were significantly higher than in Tis-2 cases. Furthermore, the G/L ratio and serum IL-6 showed a significant inverse correlation with the overall survival, while the G/L ratio showed a significant positive correlation with serum IL-6, TNF-α and M-CSF. Multivariate analysis showed that the serum IL-6 level and G/L ratio were independent risk factors for poor prognosis. Conclusions: In this investigation, a pre-operative high level of serum IL-6 and the G/L ratio appeared to be significant predictive factors for cancer progression and poor prognosis. Accordingly, these variables might be clinically relevant biomarkers in patients with colorectal cancer.