Human Epidermal Growth Factor Receptor 2 Over-Expression in Patients with Esophageal Squamous Cell Carcinoma; Correlation with Response to Neo-Adjuvant Chemoradiation and Survival

Esophageal squamous cell carcinoma (ESCC) is a common malignancy in gastrointestinal tract.
This study was conducted to investigate the frequency of human epidermal growth factor receptor 2 (HER2), over-expression in patients with ESCC, and its correlation with pathologic response in cases undergoing neo-adjuvant, chemoradiation, and survival.
In this cross sectional study, 68 patients with non-metastatic esophageal SCC, who had undergone neo-adjuvant chemotherapy containing cisplatin and 5FU in conjunction with radiotherapy between 2007 and 2014 were evaluated. HER2 expression assessed by Immunohistochemistry and HER2 score was also calculated for each specimen. Tumor response to neoadjuvant chemoradiotherapy was evaluated in surgical blocks according to tumor regression grading (TRG) system. Patients were followed up every 3 months in first 2 years and every 6 months afterwards.
The result of Hercep test was positive in 42.8% of cases, among whom 33.8% were 2 and 8.8% were 3. Her2 score was above 100 in 38.3%. Complete pathologic response was observed in 32.3%. There was no significant difference in the rate of complete response between patients with positive and negative HER-2 over-expression (P = 0.71). There was also no significant correlation between Her2 score among groups with favorable and unfavorable response to chemoradiation (P = 0.796 and 0.743). There was no difference in overall survival in Her2 positive and negative groups (3 years survival was 45 and 54 months, P = 0.32). Overall survival significantly reduced in patients with Her2 score above 100 (P = 0.045).
Her2 positive in ESCC had no effect on tumors biologic behaviors and its response to chemoradiation. Although no correlation was observed between Her2 expression and survival; Her2 score above 100 was associated with shorter survival.