HER2 expression in carcinomas of the true cardia (Siewert type II esophagogastric junction carcinoma).

ABSTRACT

OBJECTIVES: To evaluate the HER2 status in patients with Siewert type II esophagogastric junction carcinoma. BACKGROUND: Trastuzumab is now approved for use in the treatment of human epidermal growth factor receptor 2 (HER2)-positive unresectable metastatic gastric or esophagogastric junction (EGJ) carcinoma. Several studies have evaluated HER2 status in EGJ carcinoma, but none has addressed the implication of HER2 positivity in patients with Siewert type II EGJ carcinoma. METHODS: We retrospectively evaluated the frequency of HER2 positivity in a large single-center cohort of 208 patients with Siewert type II tumors. The relations between HER2 expression and the outcomes and other clinicopathologic features were examined. RESULTS: Overall, 18.2 % (38/208) of patients in our cohort had HER2-positive tumors. HER2 positivity was associated only with differentiated carcinomas. The 5-year overall survival (OS) rate was 58.7 %. The 5-year OS rates in the patient groups with HER2-negative and HER2-positive tumors were 61.2 and 48.5 %, respectively. There was no significant difference between the groups. Recurrence in the liver was observed in 23.7 % patients of the HER2-positive group and 7.6 % patients of the HER2-negative group. Multivariate analysis to identify the risk factors for liver recurrence revealed only HER2 positivity (p = 0.0155) as an independent predictive factor. CONCLUSIONS: HER2 positivity is a powerful predictor of liver recurrence in patients with Siewert type II EGJ carcinoma. Use of trastuzumab in combination with chemotherapy in an adjuvant setting can be a potentially useful therapeutic strategy to prevent hepatic recurrence in patients with resectable EGJ adenocarcinoma showing HER2 overexpression.