Small intestine cancers are rare. About 10,000 people will get this type of cancer in the United States this year, according to the American Cancer Society.
How small intestine cancer develops
Getting small intestine cancer means abnormal cells in that section of your gastrointestinal tract are growing and dividing at a rapid pace — so fast that cells in your immune system that fight disease cannot keep up. There are five types of small intestine cancer that differ depending on the type of cell affected including:
- Adenocarcinoma is the most common type of small intestine cancer; it starts in the cells that make the mucus lining on the inside of the small intestine and most often develops at the junction of the small intestine and the stomach.
- Leiomyosarcomas are rare cancers that start in smooth muscle cells in the wall of the small intestine, most often appearing near the large intestine.
- Carcinoid tumors start in hormone-making cells in the intestine.
- Gastrointestinal stromal tumors (GISTs) start in special cells found in the wall of the GI tract, called the interstitial cells of Cajal.
- Lymphomas are a type of cancer that typically start in immune system cells, but can also start in intestinal organs.