Background
Plasma IL-6 and YKL-40 are prognostic biomarkers for OS in patients with different types of solid tumors, but they have not been studied in patients before surgery of metastatic bone disease (MBD) of the extremities. The
Conclusion
High preoperative plasma IL-6 is an independent biomarker of short OS in patients undergoing surgery for MBD.
Methods
A prospective study included all patients undergoing surgery for MBD in the extremities at a tertiary referral center during the period 2014-2018. Preoperative blood samples from index surgery were included. IL-6 and YKL-40 concentrations in plasma were determined by commercial ELISA. A total of 232 patients (median age 66 years, IQR 58-74; female 51%) were included.
Results
Cox regression analysis was performed to identify independent prognostic factors for OS. IL-6 correlated with YKL-40 (rho = 0.46, p < 0.01). In univariate analysis (log2 continuous variable) IL-6 (HR = 1.26, 95% CI 1.16-1.37), CRP (HR = 1.20, 95% CI 1.12-1.29) and YKL-40 (HR = 1.25, 95% CI 1.15-1.37) were associated with short OS. In multivariable analysis, adjusted for known risk factors for survival, only log2(IL-6) was independently associated with OS (HR = 1.24, 95% CI 1.08-1.43), whereas CRP and YKL-40 were not.