The small intestine (also called small bowel) is part of the body’s digestive system. It is a long, coiled tube that connects the stomach to the large intestine. The small intestine receives food from the stomach, helps break it down, and absorbs nutrients that are used by the body. The three parts of the small intestine are the duodenum, jejunum, and ileum. The duodenum connects to the stomach, and the ileum connects to the colon.

Small intestine cancer often starts in the duodenum. The most common type of small intestine cancer is adenocarcinoma (cancer that begins in cells that make and release mucus and other fluids). Other types of small intestine cancer are sarcomas, carcinoid tumors, gastrointestinal stromal tumors, and lymphomas.