Early diagnosis of early gastric cancer

The prognosis of gastric cancer is closely related to the stage of disease at diagnosis. Early gastric cancer, whereby disease is limited to mucosa and submucosa, confers a survival rate of greater than 90% in 5 years in many centres. Gastric cancer is still a major cause of cancer mortality worldwide. In high incidence areas such as Japan, screening of asymptomatic population has been advocated. However, in Western countries, mass screening is not cost-effective. Hence, strategy has been directed to screen symptomatic individuals who are at higher risk of gastric cancer. Most patients with early gastric cancer present with symptoms indistinguishable from benign peptic ulcer disease. Screening for this group of patients improves detection rate of early gastric cancer and therefore its prognosis. Endoscopy for surveillance of premalignant lesions has been explored with this objective in mind. Serology testing for biomarkers such as pepsinogen, anti-Helicobacter pylori antibody and gastrin has been studied as an alternative to endoscopy. There is compelling evidence for the role of H. pylori in the initiation of Correa's cascade (stepwise progression from chronic active gastritis, atrophic gastritis, intestinal metaplasia, dysplasia and finally adenocarcinoma). Regression of premalignant lesions has been demonstrated with H. pylori eradication. However, it is not known whether this might effectively prevent gastric cancer in either low or high-risk population.