Gastric cancer: Synopsis and epidemiology of gastric cancer

Gastric cancer is the fifth most common cancer accounting for close to 7 % of all human cancers. Despite the decrease in incidence, gastric cancer remains the most common cause of gastrointestinal cancer-related death, with more than 800,000 fatalities annually. The disease is more common in men than in women, and non-cardia gastric cancer is twice as common as cardia cancer. More than two-thirds of gastric cancer occur in East Asia, in particular, in China, Japan, and Korea. There are large regional and racial differences in the incidence of gastric cancer. These differences are related to prevalence of Helicobacter pylori (H. pylori), diet, and other risk factors. The mortality of gastric cancer closely matches the regional differences in incidence. The age-standardized incidence and mortality rates of gastric cancer are expected to further decrease due to improvement in socioeconomic conditions and decreasing prevalence of H. pylori. Population screening and intervention, as well as general health measures such as antismoking campaigns, can accelerate the changing epidemiology of gastric cancer. In the absence of such measures, gastric cancer will for long remain a very common and lethal disease. This chapter reviews the epidemiology of gastric cancer, with focus on regional differences in incidence and mortality, risk factors for gastric cancer. It further summarizes the changing epidemiology of gastric cancer in recent decades and the expected future trends.