Serum Interleukin-6 Levels Correlate with the Efficacy of Antiangiogenic Therapy in Metastatic Colorectal Cancer

This study aims to assess the correlation between IL-6 concentration in the blood and the efficacy of antiangiogenic therapy for liver metastases from colorectal cancer. In this retrospective study, we examined 53 patients with CRLM who received non-surgical treatment from June 2017 to June 2023. We collected serum IL-6 levels before starting treatment and evaluated their impact based on consensus guidelines. The ROC curve was used to determine the best cut-off point for IL-6. We compared treatment response rates using chi-square tests and estimated overall survival (OS) and progression-free survival (PFS) using Kaplan-Meier and multivariate Cox proportional hazard regression analyses. It was observed that patients who were treated with bevacizumab had a longer progression-free survival (PFS) compared to those who did not receive it (P=0.04). Out of the 24 patients who received chemotherapy alone, 12 had a shorter PFS compared to the remaining 12 who had lower IL-6 levels (P=0.03). Among the 29 patients who were treated with the bevacizumab combination therapy, no significant difference was observed in PFS between the 19 patients who had higher IL-6 levels and the other 10 patients who had lower IL-6 levels (P=0.76). We have concluded that patients with higher levels of IL-6 benefited from antiangiogenic therapy, whereas those with lower levels did not receive the same benefits from bevacizumab.