(Cancer of the Small Intestine)
Cancerous (malignant) tumors in the small intestine are very uncommon, occurring in about 9,000 people in the United States each year. Adenocarcinoma is the most common type of cancer of the small intestine. Adenocarcinomas develop in the glandular cells of the lining of the small intestine. People with Crohn disease of the small intestine are more likely than others to develop adenocarcinoma.
Carcinoid tumors (see Carcinoid Tumors and Carcinoid Syndrome) can develop in the glandular cells that line the small intestine. Carcinoid tumors often secrete hormones that cause diarrhea and flushing of the skin. Chemotherapy and other types of drugs sometimes help control the symptoms caused by carcinoid tumors.
Lymphoma (cancer of the lymphatic system—see Overview of Lymphoma) may develop in the middle section (jejunum) or the lower section (ileum) of the small intestine. Lymphoma may cause a segment of intestine to become rigid or elongated. This cancer is more common among people with untreated celiac disease. Chemotherapy and radiation therapy can help control symptoms and sometimes lengthen survival time.
Leiomyosarcoma (cancer of smooth muscle cells) can develop in the wall of the small intestine. Chemotherapy may slightly lengthen survival time after surgery to remove leiomyosarcomas.
Adenocarcinoma may cause bleeding into the intestine, which shows up as blood in the stool, and obstruction, which in turn may lead to crampy abdominal pain, expansion (distention) of the abdomen, and vomiting. Sometimes cancers of the small intestine cause intussusception (one segment of the intestine slides into another, much like the parts of a telescope).
Doctors typically do enteroclysis. In this procedure, a large amount of barium liquid is inserted through a tube in the nose and x-rays are taken as the barium moves through the digestive tract. Sometimes this procedure is done with a computed tomography (CT—see Computed Tomography and Magnetic Resonance Imaging) scan instead of plain x-rays, in which case the person can just drink the barium rather than having a tube put through their nose.
A doctor may use an endoscope (a flexible viewing tube—see Endoscopy) passed through the mouth and down to the duodenum and part of the jejunum (the upper and middle sections of the small intestine) to locate the tumor and perform a biopsy (remove a tissue sample for examination under a microscope). A doctor can sometimes see tumors of the ileum (the lower section of the small intestine) by passing a colonoscope (an endoscope used to view the lower part of the digestive tract) through the anus, through the entire large intestine, and up into the ileum.
A wireless battery-powered capsule that contains one or two small cameras (see Video Capsule Endoscopy) can also be used to show tumors of the small intestine.
Sometimes exploratory surgery is needed to identify a tumor in the small intestine.
The best treatment for all types of cancerous growths is surgical removal of the tumor.
If doctors are able to see the tumor with an endoscope, they may also remove it by applying an electrical current (electrocautery) or heat (thermal obliteration).
Chemotherapy and radiation therapy after surgery do not lengthen survival time.