EGFR Expression in Patients with Esophageal Squamous Cell Carcinoma and its Association with Pathologic Response to Preoperative Chemoradiotherapy: A Study in Northeastern Iran.

INTRODUCTION Esophageal squamous cell carcinoma (ESCC) accounts for 80% of all esophageal cancers worldwide. It is the most common histological type of esophageal carcinoma in low-resource countries. ESCC is prevalent in Asian countries, accounting for more than 95% of esophageal cancers. The epidermal growth factor receptor (EGFR) is involved in cancer development, as its gene is often mutated and/or amplified in cancer cells. According to recent statistics, esophageal cancer is the eighth most common cancer in Iran. METHODS In this retrospective study, we assessed EGFR overexpression, using immunohistochemistry (IHC) in 68 patients with ESCC, undergoing neoadjuvant chemoradiotherapy and esophagectomy in 2011-2014. The treatment protocol included external beam radiotherapy (40 Gy), concomitant with cisplatin 20mg/m2 and 5- fluorouracil (5-FU) 1000 mg/m2 for 4 consecutive days during the first and fourth weeks of treatment. To compare the two groups (EGFR positive and negative) in terms of complete pathologic response, Chi-square test was performed using SPSS version 16. RESULTS The median age of the patients was 59 years (range: 27-70 years), with a female-to-male ratio of 1.06. Overall, 70% of the subjects showed EGFR overexpression. Complete pathologic response to neoadjuvant treatment was significantly higher in EGFR-positive patients (40% vs. 15.8%, P = 0.05). In all cases, 1- and 3-year overall survival rates were 86.6% ± 4.1 and 48% ± 6.9, respectively. The 1- and 3-year disease free survival rates were calculated as 71.8% ± 5.4 and 44.3% ± 6.5, respectively. The overall survival rate was relatively higher in cases with EGFR overexpression, although the difference was not statistically significant (5-year survival rate: 47.9 ± 8.2 vs. 30.9 ± 13, P = 0.23). CONCLUSION EGFR overexpression was reported in the majority of patients with ESCC in northeastern Iran. Moreover, EGFR overexpression was significantly associated with complete pathologic response.