Epidermal growth factor receptor gene amplification predicts worse outcome in patients with surgically resected nonadenocarcinoma lung cancer

Abstract

The epidermal growth factor receptor (EGFR) gene copy number was analyzed with fluorescent in situ hybridization (FISH) to examine the prognostic role in surgically resected nonadenocarcinoma of non-small-cell lung cancer (NA-NSCLC). Patients with EGFR gene amplification and high polysomy, who underwent curativeintent surgical resection, showed significantly shorter overall survival (hazard ratio, 1.36; 95% confidence interval, 1.040-1.782; P = .025). EGFR FISH evaluation of surgical tumor tissue, in addition to clinicopathologic factors, might better predict for the prognosis of early-stage or locally advanced NA-NSCLC patients. Purpose: The aim of the present study was to examine the prognostic role of amplification and increased expression of the epidermal growth factor receptor (EGFR) gene in surgically resected non-adenocarcinoma of non-small cell lung cancer (NA-NSCLC). Materials and Methods: The present retrospective study included 114 consecutive NA-NSCLC patients with available tumor tissue and survival data. EGFR gene copy number and protein expression were evaluated using fluorescent in situ hybridization (FISH) and immunohistochemistry in tissue microarray sections, respectively. Results: Among 114 patients, 99 (86.8%) had squamous cell carcinoma histologic features. EGFR gene amplification and high polysomy (EGFR FISH+) were observed in 7.9% and 31.6% of cases, respectively. Patients with EGFR FISH+ had significantly shorter overall survival (P = .011). A multivariate model confirmed that patients with EGFR FISH+ had a significantly greater risk of death than EGFR FISH- patients after adjusting for pathologic stage, presence of pleural invasion, venous invasion, and surgical margins (hazard ratio, 1.36; 95% CI, 1.040 to 1.782; P = .025). EGFR protein expression by immunohistochemistry was not associated with overall survival in the same group. Neither EGFR gene amplification nor EGFR immunohistochemistry expression was associated with relapse-free survival. Conclusion: An increased EGFR gene copy number in surgically resected NA-NSCLC was associated with worse survival. (C) 2018 Elsevier Inc. All rights reserved.