Gastrointestinal Carcinoid Tumors Facts

Gastrointestinal carcinoid tumors form in the lining of the gastrointestinal tract, which includes the stomach, small intestine, colon and rectum. Approximately 8,000 of those cases are diagnosed each year in the United States, according to the American Cancer Society.

How Gastrointestinal Carcinoid Tumors Develop

Gastrointestinal (GI) carcinoid tumors start in the neuroendocrine system, which is made up of cells that resemble nerve cells and hormone-making cells in the gastrointestinal tract. These cells control the production of digestive juices and the muscles that guide food and waste through the stomach and intestines. Cells in this system are not concentrated in a particular organ; they are found in several areas of the body but tend to be concentrated in the gastrointestinal (GI) tract.

Like other types of cancer, GI carcinoid tumors form when abnormal neuroendocrine cells grow uncontrollably, joining together to form a growth called a tumor. GI carcinoid tumors are rare and grow very slowly.

What Increases Your Risk Of GI Carcinoid Tumors?

  • Multiple endocrine neoplasia type 1 is a rare condition caused by inherited abnormalities in a gene called MEN1 that increases the risk of developing tumors in the pituitary, pancreatic and parathryoid glands.
  • Neurofibromatosis type 1 is caused by problems with the NF1 gene and can lead to developing benign tumors called neurofibromas.
  • Conditions that affect stomach acid production, such as atrophic gastritis, Zollinger-Ellison syndrome and pernicious anemia, may increase risk.
  • Race and gender: African-Americans are more likely than other groups to develop GI carcinoid tumors and, overall, women have a slightly higher risk than men of developing carcinoid tumors.
  • Other medical conditions, including diseases affecting stomach acid production, may result in an increased risk of developing carcinoid tumors in the stomach.

GI Carcinoid Cancer Symptoms

Symptoms associated with GI carcinoid tumors depend on what area of the gastrointestinal system is affected. In some areas, these tumors build up and cause no symptoms while in others, the symptoms can be significant, including:

Other medical conditions share these symptoms. If you are treated for these conditions and they do not go away, you may need further consultation to rule out GI cancer.