Gastric cancer: Synopsis and epidemiology of gastric cancer

Gastric cancer (GC) is the ffth most common cancer accounting for close to 7% of all human cancers. Despite the decrease in incidence, GC 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 noncardia GC is twice as common as cardia cancer. More than two-thirds of GC occur in East Asia, in particular, in China, Japan, and Korea. There are large regional and racial differences in the incidence of GC. These differences are related to prevalence of Helicobacter pylori (H. pylori), diet, and other risk factors. The mortality of GC closely matches the regional differences in incidence. The agestandardized incidence and mortality rates of GC 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 GC. In the absence of such measures, GC will for long remain a very common and lethal disease. This chapter reviews the epidemiology of GC, with focus on regional differences in incidence and mortality, risk factors for GC. It further summarizes the changing epidemiology of GC in recent decades and the expected future trends.