Intestinal cancer causes and risk factors

This page was reviewed under our medical and editorial policy by

Maurie Markman, MD, President, Medicine & Science.

This page was updated on September 12, 2022.

Intestinal cancer is an overgrowth of cancerous cells in the small intestine, which is part of the digestive system. This long, narrow tube connects the stomach to the large intestine.

Intestinal cancer, also called small intestine cancer, is much less common than other cancers of the gastrointestinal (GI) tract, such as colorectal cancer and stomach cancer. According to the American Cancer Society, fewer than one in 10 GI malignancies are cancers of the small intestine. Across all cancers, small intestine cancer is responsible for fewer than one in 100 cases. According to the National Cancer Institute, an estimated 0.3 percent of people in the United States will develop cancer of the small intestine during their lifetime.

While the exact cause of intestinal cancer may not be known, several factors may increase the risk of developing the disease. Statistics show that men are slightly more likely to develop the disease than women. Small intestinal cancer also tends to occur more often in older people and is most often found in people in their 60s and 70s.


  • Age: According to the National Cancer Institute, the average age of diagnosis is 67.
  • Gender: Men are slightly more likely to develop the disease than women.


Inherited condition: Although most small intestine cancers occur without a known hereditary link, there are some inherited conditions that may lead to a higher risk. The inherited conditions associated specifically with small intestine adenocarcinoma are:

  • Familial adenomatous polyposis (FAP)
  • Hereditary nonpolyposis colorectal cancer (HNPCC), also called Lynch syndrome
  • Peutz-Jeghers syndrome (PJS)
  • Cystic fibrosis (CF)
  • People with either multiple endocrine neoplasia, type I (MEN1) or defects in the gene NF1 (type 1 neurofibromatosis) may develop benign tumors in the small intestine that are at risk of becoming malignant carcinoid tumors.
  • Gardner syndrome: Caused by a genetic defect. People with this syndrome often develop many polyps throughout the GI tract, particularly in the colon. Although there is a greater risk for developing colon cancer, this disease is considered a risk factor for sarcomas of the small intestine.
  • Von Recklinghausen's disease: Neurofibromatosis, an inherited gene mutation, may lead to GISTs. However, there usually is no known cause for GISTs of the small intestine and hereditary links are rare.

Learn more about genetic testing


  • Tobacco and alcohol use: Lots of evidence links cigarette smoking and alcohol abuse to many types cancer. Some research suggests that smoking and drinking may also be associated with small intestine cancer.
  • Diet: Eating a high-fat diet may be a small intestine risk factor.
  • Chemical exposure: Certain chemicals, like vinyl chloride, dioxins and high doses of herbicides containing phenoxyacetic acid, are considered intestinal cancer risk factors for certain types of sarcomas, possibly including sarcomas in the small intestine.

Other conditions

  • Gastrointestinal diseases: Certain diseases that affect the gastrointestinal (GI) tract may increase the risk of developing small intestine cancer. For example, Crohn's disease is a condition in which the immune system harms the small intestine. If you have had colon cancer, you may also be at an increased risk for small intestine adenocarcinoma, possibly because both cancers share similar risk factors. The GI diseases that are considered risk factors for small intestine cancer are:
  • Lymphedema: Damage to the lymph vessels (the vessels that connect the lymph nodes) or an infection may cause lymph fluid to build up. Lymphedema is also sometimes referred to as elephantiasis. This may increase your risk of developing a sarcoma of the small intestine.

Next topic: What are the symptoms of intestinal cancer?

Expert cancer care

is one call away.
appointments in as little as 24 hrs.