Elevated Serum Interleukin-6 Levels Lead to Poorer Treatment Outcomes in Patients with Metastatic Colorectal Cancer, a Pathway That Can Be Interrupted by Bevacizumab

Purpose: To evaluate the relationship between serum IL-6 concentration and the efficacy of anti-angiogenic therapy in patients with liver metastases from colorectal cancer. Methods: : Serum IL-6 and CEA levels were retrospectively analyzed in 53 patients with colorectal cancer with liver metastases at first diagnosis, and the optimal cut-off values for these data were 4.83 ng/ml and 4.85 ng/ml, respectively, according to the ROC curve; the median follow-up time was in the range of 16 months (6-53 months), and the diameters of liver metastases were recorded at the first diagnosis and two months after the start of the first treatment. All 53 patients were found to have colorectal cancer combined with liver metastases at the first visit, and none of the metastases were treated surgically (including arterial catheter embolization). Twenty-six patients underwent resection of the primary lesion to reduce tumor load, 24 received oxaliplatin-based chemotherapy alone, and 29 received chemotherapy including bevacizumab. Overall survival (OS) and progression-free survival (PFS) were estimated using Kaplan-Meier and multivariate Cox proportional risk regression analysis. Results: : The chi-square test verified that high serum IL-6 levels were significantly associated with lower treatment efficiency in patients treated with chemotherapy alone. However, this correlation can not be observed in patients treated with bevacizumab. Conclusion: IL-6 can VEGF-dependently promote tumor angiogenesis; and anti-angiogenic therapy can eliminate the adverse effects of high levels of il-6 in patients with advanced colorectal cancer.