Gastric cancer: endoscopic diagnosis and staging.

Gastric cancer is common and is a cause of severe morbidity and mortality. Early diagnosis can improve the chances of cure and prolong survival because prognosis is inversely related to the disease stage. Endoscopy plays an important role in diagnosis. Emerging adjunct technologies such as image-enhanced endoscopy and magnification endoscopy aid in early cancer detection. Endoscopic ultrasonography is an additional useful tool for preoperative staging. Endoscopy for screening, except for high-risk patients, and outside areas of high prevalence, remains controversial.