Prognostic value of circulating cytokines for stage III colon cancer.

BACKGROUND: This study was to determine preoperative serum levels of epidermal growth factor (EGF), interleukin-6 (IL-6), and C-reactive protein (CRP) in stage III colon cancer and correlate them with disease status and prognosis. The circulating EGF in correlation with primary site epidermal growth factor receptor (EGFR) was also evaluated.
METHODS: Seventy-seven patients with curatively resected stage III colon cancer were selected for analysis. Enzyme-linked immunosorbent assay was used to determine EGF and IL-6 serum levels, and serum CRP levels were measured via immunoturbidimetry. EGFR expression was observed with immunohistochemical studies.
RESULTS: The median levels of EGFR, IL-6, and CRP were 189.4 pg/mL, 9.09 pg/mL, and 1.4 mg/mL, respectively. The factors related to recurrence with statistical significance included positive node status (P = 0.041), lymphovascular invasion (P = 0.001), and preoperative IL-6 level ≥9 pg/mL (P = 0.020). CRP and EGF levels were not significantly associated with disease-free survival rates (P = 0.438 and P = 0.309, respectively). Multivariate analysis using Cox's proportion model revealed that lymph node status was the single independent prognostic factor for predicting time until recurrence (odds ratio, 4.99; 95% confidence interval, 1.09-22.91; P = 0.038).
CONCLUSION: IL-6 expression in stage III colon cancer patients appears to be a prognostic marker of tumor behavior. No correlations between serum EGF concentrations and tumor EGFR positivity were found in this study.