The small intestine, or small bowel, lies between the stomach and the colon. The small intestine is about 6 m (20 ft) 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.
Someone without any risk factors can develop cancer, and having a risk factor, or even several, does not mean that you will get the disease. Because small intestine adenocarcinoma is so uncommon, risk factors for this disease have been hard to study. Some of the known risk factors include:
- 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 tumours 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.
- Tobacco and alcohol use: There is a lot of evidence linking cigarette smoking and alcohol abuse to many types cancer. Some research suggests that smoking and drinking may also be associated with the development of 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 to be intestinal cancer risk factors for certain types of sarcomas, possibly including sarcomas in the small intestine.
- 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:
- Colon cancer
- Celiac disease
- Crohn's disease
- 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.
Read more articles on Small Intestine Cancer.