Stomach cancer. Gastroscope (endoscope) view of a gastric adenocarcinoma (centre), a type of stomach cancer. An adenocarcinoma is a cancer which arises from glandular tissue in an organ's epithelium (lining). Stomach cancer causes symptoms similar to those of indigestion or a peptic (gastric) ulcer, and may develop undiagnosed until it has spread beyond the stomach. In such a case, the prognosis is poor, although radiotherapy and chemotherapy may slow its progress. If it is discovered early, a gastrectomy (removal of the stomach) may effect a cure. Stomach cancer is thought to be linked to diet, with a high intake of salty and smoked foods increasing the risk.