Early Gastric Cancer and Dysplasia

Gastric adenocarcinoma is the second leading cause of global cancer mortality, with nearly 1million cases annually. Gastric cancer hasmarked geographic and ethnic variability (with high-incidence areas in Eastern Asia, Latin America, parts of Europe, and the Middle East, and increased rates in certain ethnic groups such as Asians, Hispanics, and African Americans). In Western countries, early gastric cancer (EGC) accounts only for 15% to 21% of gastric cancer. Early detection is particularly important, because EGC has a much better prognosis than more advanced stages of gastric adenocarcinoma, with a 5-year survival rate of approximately 90%. EGC is defined as gastric cancer that invades the mucosa and submucosa, irrespective of lymph node metastases (T1, any N), and is of particular importance in Eastern Asia. In Japan, the incidence of EGC is higher than in the western population anywhere, from 15% to as high as 57%, because screening programs were implemented many decades ago.