The Prognostic Value Of Serum Il-6 And Ykl-40 In Patients With Metastatic Colorectal Cancer.

e15060 Background: The prognostic value of serum IL-6, YKL-40 and CEA before first (1) and third line therapy (3LT) in metastatic colorectal cancer (mCRC) is lacking and was evaluated in this study. Methods: From 2004 to 2015 serum samples were collected from 160 and 255 patients with mCRC before 1LT and 3LT, respectively. Median age was 64 years (range 33-87) and male/female ratio 243(59%)/172(41%). Serum IL-6 (R&D, UK) and YKL-40 (Quidel, USA) were determined by ELISA. Progression-free (PFS) and overall survival (OS), crude and adjusted hazard ratios (HR) and corresponding 95% confidence intervals (CI) were estimated with Cox regression analysis. CEA, IL-6 and YKL-40 were included as log2-transformed continuous variables with mutual adjustment between CEA, IL-6 and YKL-40, primary tumor location, sex and age. Results: In 3LT IL-6, YKL-40 and CEA levels were higher (P < 0.001) than in 1LT (IL-6: 9.5 pg/ml [IQR4.2-18.5] vs. 4.6 [2.5-10.5]; YKL-40: 140 ng/ml [77-272] vs. 101 [62-172]; and CEA: 59 ug/l [14-288] vs. 23[5.8-153]). In 3LT univariate analysis showed that increased levels of IL-6, YKL-40 and CEA were associated with shorter PFS (IL-6: HR = 1.19, 95% CI 1.07-1.31, P < 0.01; YKL-40: HR = 1.13, 1.04-1.24, P = 0.01; CEA: HR = 1.05, 1.00-1.09, P = 0.04). In 1LT only high IL-6 was associated with shorter PFS (HR = 1.09, 1.01-1.17, P = 0.03). In a multivariate analysis only high IL-6 was significantly associated with shorter PFS in 3LT (HR = 1.15, 1.03-1.29, P < 0.01) and none of the biomarkers in 1LT. In 3LT univariate analysis showed that increased levels of all 3 biomarkers were associated with a shorter OS (IL-6: HR = 1.36, 1.23-1.51, P < 0.01; YKL-40: HR = 1.21, 1.10-1.33, P < 0.01; CEA: HR = 1.11, 1.06-1.16, P < 0.01). In 1LT high levels of IL-6 (HR = 1.17, 1.08-1.27, P < 0.01) and YKL-40 (HR = 1.18, 1.00-1.38, P = 0.05), but not CEA, were associated with short OS. In 3LT the multivariate analysis showed that both higher IL-6 (HR = 1.34, 1.20-1.50, P < 0.01) and CEA (HR = 1.09, 1.03-1.14, P < 0.01), but not YKL-40 were significantly associated with a shorter OS. In 1LT only higher IL-6 was associated with a shorter OS (HR = 1.19, 1.08-1.31, P < 0.01) Conclusions: Serum IL-6 and YKL-40 may be useful prognostic biomarkers in combination with CEA in patients with mCRC