Correlation of serum interleukin-6 (IL-6) levels and clinical outcome in hormone-independent (HI) prostate cancer (PC) patients (PTS) treated with docetaxel

Abstract

e16044 Background: IL-6 acts as an autocrine and paracrine growth factor in PC, linked to HI progression. We previously reported preliminary data on the correlation of serum IL-6 and D response in metastatic HI PC pts. We present here a larger group of pts tested to asses the clinical relevance of IL-6 in these pts. Methods: Pts with HIPC treated with D were prospectively tested for IL-6 levels by ELISA before D. Prostate-specific antigen (PSA) response, time to PSA progression, overall survival (OS) and PC specific survival (SpS) were analyzed. Evaluated variables were age, performance status, PSA, Gleason, number (n) of D cycles, time to HI progression, presence of visceral metastasis, n of bone metastasis, hemoglobin, lactate deshydrogenase and alkaline phosphatase. Results: Seventy-two pts were included. At the time of the analysis 5 pts had died from non-PC related causes, two from treatment toxicity and 29 (40%) from PC. Mean of age was 69 ± 7 years. Median baseline IL-6 level was 14 pg/ml (range 0.1–1100). Thirty-five pts (49 %) had IL-6 levels > 14 pg/ml. IL-6 > 14 pg/ml correlated with lower D response (13 % vs 40%, p= 0.039); lower time to PSA progression (4 months vs 6, p=0.023); lower OS (10 months vs 25, p= 0.001) and lower PC SpS (12 months vs 26, p= 0.001), in contrast to pts with IL-6 ≤ 14pg/ml. In the multivariate analysis, serum IL-6 (p=0.002), n of bone metastasis (p=0.008) and n of D cycles (p=0.002), were independent prognostic factor for OS and PC SpS. Conclusions: High serum IL-6 correlates with an adverse clinical outcome of pts with HIPC treated with D. IL-6 determination may be a potential tool to select patients for D-based or targeted therapies. FIS ( PI070388 ) No significant financial relationships to disclose.