Combined detection of preoperative neutrophil to lymphocyte ratio and interleukin-6 as an independent prognostic factor for patients with non-metastatic colorectal cancer

Background: This study sought to explore the value of the neutrophil to lymphocyte ratio (NLR) and interleukin-6 (IL-6) in predicting the prognosis of patients with non-metastatic colorectal cancer (CRC). Methods: The data of 88 surgical CRC patients were retrospectively analyzed. A receiver operating characteristic (ROC) curve analysis was conducted to determine the patients' thresholds for the NLR and IL-6. Kaplan-Meier curve and Cox regression models were used to assess the prognostic values. Results: A ROC analysis was conducted to calculate the NLR cut-off value. The area under the curve (AUC) of the NLR was 0.739 [95% confidence interval (CI): 0.634 to 0.844] for overall survival (OS), and 0.799 (95% CI: 0.705 to 0.892) for disease-free survival (DFS). The AUC of IL-6 was 0.773 (95% CI: 0.670 to 0.876) for OS, and 0.817 (95% CI: 0.728 to 0.906) for DFS. The AUC of NLR + IL-6 was 0.805 (95% CI: 0.710 to 0.899) for OS and 0.853 (95% CI: 0.774 to 0.933) for DFS, which were higher than the NLR or IL-6 alone AUCs for OS and DFS. In addition, a high NLR and IL-6 value was significantly correlated with tumor differentiation and tumor-node-metastasis staging. The NLR was positively correlated with IL-6 level (r=0.481). The results of the Kaplan-Meier analysis showed that a high NLR + IL-6 value was correlated with worse OS and DFS. Conclusions: A high NLR and IL-6 value is a better independent prognostic biomarker of CRC than the NLR or IL-6 level alone, and may be applied in clinical practice to identify high-risk patients.