Basics of Small Bowel Cancer The small intestine, or small bowel, lies between the stomach and the colon. The small intestine is about 20 feet long. Its primary function is to digest and absorb nutrients. The small intestine makes up more than 70% of the length and 90% of the surface area of the gastrointestinal (GI) tract.

Cancerous (malignant) tumors of the small intestine include adenocarcinoma, carcinoid, gastrointestinal stromal tumor, lymphoma, and cancer that has spread from other places in the body. All these tumors have the potential to invade the bowel wall, move into adjoining lymph nodes, and spread to distant organs (metastasize).

• In industrialized countries, adenocarcinomas occur most often.
• In developing countries, lymphomas are much more common.

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