Epidermal growth factor receptor as a prognostic factor in locally advanced rectal-cancer patients treated with preoperative chemoradiation

Abstract

We investigated the prognostic value of epidermal growth factor receptor (EGFR) expression in pretreatment biopsy specimens from patients with locally advanced rectal cancer treated with preoperative chemoradiation. Pretreatment biopsy specimens from 92 patients with locally advanced rectal cancer were examined for EGFR expression by immunohistochemistry. EGFR expression was assessed by immunoreactive score (IRS). The prognostic value of EGFR expression was evaluated according to the level of EGFR expression. Epidermal growth factor receptor expression was positive in 65 patients (71%). EGFR expression levels were low (IRS 0 to 5) in 83 patients (90%) and high (IRS 6 to 7) in 9 patients (10%). A high level of EGFR expression was statistically significant for shorter overall survival (p = 0.013), disease-free survival (p = 0.002), and distant metastasis-free survival (p = 0.003), as compared with a low level of expression in univariate analysis. Grouping based on positive or negative EGFR expression did not represent prognostic significance for survival. In multivariate analysis, high EGFR expression was an independent prognostic factor for decreased disease-free survival (relative risk 2.4, p = 0.041) and distant metastasis-free survival (relative risk 2.6, p = 0.04). Our results suggest that high level of EGFR expression in a pretreatment biopsy specimen may be a significant adverse prognostic factor for disease-free survival and distant metastasis-free survival.