Cancer of the stomach. Illustration of a sectioned view of the stomach (right) and the duodenum (left, first part of the small intestines), showing a malignant (cancerous) tumour of the stomach at upper left. This cancerous infiltration is limited to the pylorus region of the stomach, the area that forms the junction between the stomach and the duodenum. The wall of the stomach has thickened here, narrowing this area. Stomach cancer is usually a glandular cancer (adenocarcinoma) of its inner lining. At an advanced stage the chances of recovery are poor. Treatment involves surgical excision and courses of radiotherapy and chemotherapy.