Gastric cancer epidemiology and risk factors.

Gastric cancer is a prevalent yet heterogeneous disease. From diet and lifestyle to genetics and ethnicity, our appreciation of the complexity of gastric cancer has evolved. This review will discuss the epidemiology of gastric cancer focusing on trends across various risk categories. We realize that gastric cancer is not merely a single disease, but rather individual diseases within a single organ-a distinction that will aid our understanding of disease heterogeneity and its significance.