What Are the Risk Factors for Gastrointestinal Carcinoid Tumors?

A risk factor is anything that affects your chance of getting a disease such as cancer. For example, exposure to strong sunlight is a risk factor for skin cancer, while smoking is a risk factor for cancer of the lung and several other cancers.

But risk factors don’t tell us everything. Someone without any known risk factors can still develop cancer. And someone can have a risk factor, but still not get the disease. Only a few risk factors for gastrointestinal (GI) carcinoid tumors are known.

Genetic syndromes

Multiple endocrine neoplasia, type I

This is a rare condition caused by inherited defects in the gene MEN1. People with this syndrome have a very high risk of getting tumors of 3 glands: the pituitary, parathyroid, and pancreas. They also have an increased risk of carcinoid tumors. Some studies estimate that inherited mutations of the MEN1 gene are responsible for about 10% of carcinoid tumors. Most of these are gastric (stomach) carcinoids. Children have a 50/50 chance of inheriting this syndrome from an affected parent.

If your family is affected by the MEN1 syndrome, you might want to talk to your doctor about the pros and cons of getting tested for it. Although the gene that causes tumors in people with the MEN1 syndrome has been found, genetic testing for MEN1 is not widely available. Because the results of genetic testing are not always clear cut, it is important that the test is done along with genetic counseling to help you make sense of the results.

Neurofibromatosis type 1

This disease often runs in families and is characterized by many neurofibromas (benign tumors that form in nerves under the skin and in other parts of the body). It is caused by defects in the NF1 gene. Some people with this condition also develop neuroendocrine tumors of the small intestines.

Other genetic syndromes

Neuroendocrine tumors are also more common among people with tuberous sclerosis complex and von Hippel Lindau disease. Tuberous sclerosis complex can be caused by a defect in the TSC1 or TSC2 gene. People with this condition can also develop tumors of the heart, eyes, brain, lungs, and skin. People with von Hippel Lindau disease have an inherited tendency to develop blood vessel tumors of the brain, spinal cord, or retina, as well as kidney cancer. It is caused by changes in the VHL gene.

To find out more on being tested for genetic syndromes, see Genetic Testing: What You Need to Know.

Race and gender

Carcinoid tumors are more common among African Americans than whites. Outcomes are also not as good for African Americans. Researchers do not yet know why. Carcinoid tumors are also slightly more common in women than men.

Other stomach conditions

People with certain diseases that damage the stomach and reduce the amount of acid it makes have a greater risk of developing stomach carcinoid tumors, but their risk for carcinoid tumors of other organs is not affected.

Factors with uncertain or unproven effects


Smoking may increase the risk of getting a carcinoid tumor of the small intestine, according to some research. But further studies are needed to confirm this.


The risk of developing GI carcinoid tumors does not appear to be increased or decreased by any specific foods.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master's-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Last Medical Review: February 26, 2015 Last Revised: February 8, 2016

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