Prognostic impact of preoperative serum interleukin-6 levels in patients with early-stage oral squamous cell carcinoma, defined by sentinel node biopsy

Abstract

Failure to detect recurrence and lymph node metastasis early represents a fundamental barrier to the improvement of survival rate in early stage oral squamous cell carcinoma (OSCC). The present study evaluated the association between serum interleukin-6 (IL-6) level and clinical outcomes in patients with early stage OSCC patients defined by sentinel node biopsy (SNB). A total of 53 patients with clinical stage I/II OSCC who underwent SNB were enrolled. SNB was determined by a radioisotope method, and was evaluated by histopathological examination and genetic analysis. Preoperative sera were measured for IL-6 by ELISA. In the clinical stage I/II patients, disease-free survival (DFS) was demonstrated to be higher in patients with negative SNB compared with patients with positive SNB. In total, 13 patients were demonstrated to exhibit lymph node metastasis by SNB or were reclassified to pathological stage T4 subsequent to analysis of the surgically resected specimens. Thus, 40 patients were diagnosed with early stage OSCC. Of these 40 patients, DFS of the patients with low serum IL-6 was significantly higher compared with the patients with high serum IL-6 (P=0.012). In 19 patients with negative SNB and low serum IL-6, the disease-free rate was 100%. These findings suggested that SNB staging and serum IL-6 level have a high prognostic value in patients with early stage OSCC. Additional investigation and longer follow-up times are warranted to improve understanding of the group of patients that may benefit from this procedure.

Keywords: biomarker; interleukin-6; oral squamous cell carcinoma; sentinel node biopsy.

Figure 1.

(A) SNB procedure and (B) diagnosis of pathological stage. SNB, sentinel node biopsy; OSNA, one step nucleic acid amplification.

Figure 2.

Kaplan-Meier survival plots comparing (A) SNB and OS, (B) SNB and DFS, (C) serum IL-6 levels and OS, (D) serum IL-6 levels and DFS in all cases, and (E) serum IL-6 levels and OS and (F) serum IL-6 levels and DFS in patients with pT1-2 oral squamous cell carcinoma. SNB, sentinel node biopsy; OS, overall survival; DFS, disease-free survival; IL-6, interleukin-6; p, pathological stage.