EGFR Gene Copy Number Gain is Related to High Tumor SUV and Frequent Relapse after Adjuvant Chemotherapy in Resected Lung Adenocarcinoma

Objective: The purpose of our study was to define the prognostic impact of increased copies of epidermal growth factor receptor (EGFR) gene in lung adenocarcinoma patients receiving adjuvant chemotherapy after surgery. Methods: The study included 95 adenocarcinoma patients who received curative resection for non-small cell lung cancer. Patients received adjuvant chemotherapy composed of paclitaxel and carboplatin. We performed fluorescent in situ hybridization on tissue microarray in duplicate to detect EGFR copy number change. Results: The EGFR fluorescent in situ hybridization result was available in 93 patients with a positive rate of 32.6%. EGFR copy number change did not correlate with age, gender or smoking history. However, EGFR copy number gain was related to high tumor standardized uptake value at diagnosis (P = 0.042). An increase in EGFR copy number was a negative prognostic factor in terms of disease-free survival (median disease-free survival not reached versus 23.6 months, P = 0.037) and overall survival (median overall survival 74.6 versus 43.5 months, P = 0.032). An increase in EGFR copy number was independently related to short disease-free survival in multivariate analysis (hazard ratio 2.039, P = 0.025). Conclusions: EGFR copy number gain is associated with aggressive tumor biology and is a poor prognostic factor for tumor relapse in resected lung adenocarcinoma patients receiving adjuvant chemotherapy of paclitaxel and carboplatin.