DOS 2019

DOS Kongressen 2019 · 167 Plasma YKL-40 and IL-6 are prognostic for survival after surgery for metastatic bone disease of the extremities Michala Skovlund Sørensen, Thomas Colding-Rasmussen, Peter Frederik Horstmann, Klaus Hindsø, Christian Dehlendorff, Julia Johansen, Michael Mørk Petersen Musculoskeletal tumour section, Department of Orthopaedic Surgery, Rigshospitalet, University of Copenhagen; Paediatric section, Department of Orthopedic Surgery, Rigshospitalet, University of Copenhagen; Unit of Statistics and Pharmacoepidemiology, Danish Cancer Society Research Center; Departments of Oncology and Medicine, Herlev and Gentofte Hospital, University of Copenhagen; Musculoskeletal tumour section, Department of Orthopaedic Surgery, Rigshospitalet, University of Copenhagen Background: YKL-40 is up-regulated in diseases characterized by inflammation, injury, and remodeling. High YKL-40 concentrations in patients with different cancer types are associated with short overall survival (OS). Interleukine-6 (IL-6) plays a role in inflam- mation and high IL-6 is a prognostic for short OS in different cancer types. The prognos- tic value for YKL-40 and IL-6 in patients undergoing surgery for metastatic bone disease (MBD) is unknown. Purpose / Aim of Study: The aims of study were to identify (1) if plasma YKL- 40 is associated with OS in patients undergoing surgery for MBD and (2) if this association was independent of plasma IL-6 levels. Materials and Methods: A prospective study including patients undergoing surgery for MBD in the extremities at a tertiary referral center. In case of multiple surgeries during the inclusion period (May 2014-November 2018) only blood samples from index sur- gery were included also excluding revison surgeries. Blood samples were collected pre- operatively. YKL-40 and IL-6 concentrations were determined by ELISA. Two-hundred- thirty-two patients (median age 66 years, IQR 58-74; female 51%) were included. Eighty-two percent of the patients had disseminated disease at time of surgery and 70% of the treated lesions were completely fractured. Cox regression analysis was performed to identify if YKL40 and IL-6 was independent prognostic factors for OS. Spearmann’s test was used to adress correlation between YKL-40 and IL-6. Findings / Results: Plasma IL-6 and YKL-40 were significantly correlated (rho: p<0.001). In univariate analysis, both high plasma IL-6 (> 50 percentile: HR=1.99, 95% CI: 1.47-2.68, p<0.001) and YKL-40 (age- adjusted >50 percentiles: HR=1.59, 95% CI: 1.10-2.32, p=0.014) were associated with short OS. In multivariable analysis, adjusted for known risk factors for survival, high IL-6 was prognostic for short OS (HR=2.21; 95% CI 1.41-3.19, p<0.001) but YKL-40 was not (HR=1.00, 95% CI: 0.64-1-56, p=0.99). Conclusions: IL-6 and YKL-40 were associated with short OS in patients undergoing surgery for MBD. After adjusting for known clinical risk factors for poor OS only IL-6 remained significantly associated with OS. We therefore advocate for adjusting for IL-6 in prognostic studies of OS in MBD disease 123.