Stomach cancer. Light micrograph of a section through a stomach with adenocarcincoma (top left), a type of stomach cancer that arises from glandular tissue. This is the most common type of cancer in the stomach and occurs mainly in men over 55. Risk factors excessive intake of salt in the diet, infection with the bacteria Helicobacter pylori, and smoking. Symptoms include indigestion, pain, difficulty swallowing and nausea or vomiting. Treatment is with surgery to remove the tumour, combined with chemotherapy.