Incidence of brain metastases in HER2+ gastric or gastroesophageal junction adenocarcinoma

Abstract

Gastric or gastroesophageal junction (GEJ) adenocarcinoma represents a major health issue, being the 3rd cause of death by cancer in the world. In industrialized countries, the incidence of GEJ cancers continues to rise, while gastric cancers have declined over the past few decades.The human epidermal growth factor 2 (HER2) gene is a well-described proto-oncogene. HER2 gene amplification and protein overexpression have been mostly studied in breast cancer, where HER2 overexpression was reported in 15-20% of cases.In breast cancer, HER2 overexpression is associated with a higher risk of brain metastases and significantly worse survival [1]. The prognostic value of HER2 overexpression in gastric and GEJ adenocarcinomas remains controversial. A recently published systematic review was inconclusive in patients after curative surgery [2]. The standard of care in advanced gastric carcinoma patients has changed recently, with the results of the ToGa phase III trial adding trastuzumab to chemotherapy in patients with HER2 overexpression [3]. The study indicated that this subgroup of patients benefit from trastuzumab with a three months improvement of overall survival.The aim of this study was to seek if the correlation between HER2 overexpression and brain metastases exists in gastric or GEJ adenocarcinomas, where brain metastases are uncommon.