Clinical significance of preoperative serum concentrations of interleukin-6 as a prognostic marker in patients with esophageal cancer.

Abstract

Although the clinical outcome of esophageal cancer has recently improved, the relapse rate remains high for all disease stages. At present, there is no diagnostic method to predict the long-term outcome for esophageal cancer. In this study, we evaluated serum preoperative proinflammatory cytokine levels and investigated the correlation between preoperative interleukin-6 (IL-6) and IL-8 levels and survival of patients with esophageal cancer. Between 2008 and 2015, we evaluated preoperative serum cytokine levels in 122 patients who underwent esophagectomy for esophageal cancer. Serum IL-6 and IL-8 levels were measured by enzyme-linked immunosorbent assays. We investigated the relationship between serum cytokine levels and the response to chemotherapy and survival. The preoperative IL-6 levels were significantly associated with shorter recurrence-free survival (RFS, p = 0.001) and overall survival (OS, p = 0.001) after esophagectomy. Higher IL-8 levels were significantly associated with RFS (p = 0.018). In the multivariate analysis, age, preoperative chemotherapy, lymph node metastasis, serum C-reactive protein (CRP) levels and serum IL-6 levels (hazard ratio (HR), 2.888; p = 0.049) were significantly independent prognostic factors of RFS. Additionally, age, pathological stage, and serum IL-6 levels (HR, 3.247; p = 0.027) were shown to be significantly independent prognostic factors of OS. Serum IL-6 levels were significantly higher in the non-responder group (pathological response pGrade0 and pGrade1) after neoadjuvant therapy. High preoperative serum IL-6 levels are associated with a poor response to chemotherapy or chemoradiotherapy and poor prognosis after esophagectomy. Preoperative serum IL-6 levels may be a useful independent prognostic marker for esophageal cancer patients.