Gastric cancer: a primer on the epidemiology and biology of the disease and an overview of the medical management of advanced disease.

Gastric cancer is a cause of significant morbidity and cancer-related mortality worldwide. Despite recent advances in targeted therapy and understanding of the biology and development of the malignancy, progress in the treatment of gastric cancer has been limited. Most newly diagnosed patients will present with incurable disease, and have a median survival of less than 1 year. Although the disease has widespread ethnic and epidemiologic differences, medical management of gastric cancer does not distinguish among the various disease subtypes. The recent report of the ToGA phase III study has validated Her2 as a molecular target in this disease, supporting the concept that a greater understanding of the biology of gastric cancer subsets may improve treatment selection and overall outcome of individual patients. This article summarizes the epidemiology and ethnic variation of this disease to crystalize subtypes of gastric cancer in the context of current and future medical management of advanced disease.