Gastrointestinal Carcinoid Tumors

by National Cancer Institute

General Information About Gastrointestinal Carcinoid Tumors

A gastrointestinal carcinoid tumor is cancer that forms in the lining of the gastrointestinal tract.

The gastrointestinal tract includes the stomach, small intestine, and large intestine. These organs are part of the digestive system, which processes nutrients (vitamins, minerals, carbohydrates, fats, proteins, and water) in foods that are eaten and helps pass waste material out of the body. Gastrointestinal carcinoid tumors develop from a certain type of hormone-making cell in the lining of the gastrointestinal tract. These cells produce hormones that help regulate digestive juices and the muscles used in moving food through the stomach and intestines. A gastrointestinal carcinoid tumor may also produce hormones. Carcinoid tumors that start in the rectum (the last several inches of the large intestine) usually do not produce hormones.

Gastrointestinal carcinoid tumors grow slowly. Most of them occur in the appendix (an organ attached to the large intestine), small intestine, and rectum. It is common for more than one tumor to develop in the small intestine. Having a carcinoid tumor increases a person's chance of getting other cancers in the digestive system, either at the same time or later.

Health history can affect the risk of developing gastrointestinal carcinoid tumors.

Risk factors include the following:

• Having a family history of multiple endocrine neoplasia type 1 (MEN1) syndrome.
• Having certain conditions that affect the stomach's ability to produce stomach acid, such as atrophic gastritis, pernicious anemia, or Zollinger-Ellison syndrome.
• Smoking tobacco.

A gastrointestinal carcinoid tumor often has no signs in its early stages. Carcinoid syndrome may occur if the tumor spreads to the liver or other parts of the body.

The hormones produced by gastrointestinal carcinoid tumors are usually destroyed by blood and liver enzymes. If the tumor has spread to the liver, however, high amounts of these hormones may remain in the body and cause the following group of symptoms, called carcinoid syndrome:

• Redness or a feeling of warmth in the face and neck.
• Diarrhea.
• Shortness of breath, fast heartbeat, tiredness, or swelling of the feet and ankles.
• Wheezing.
• Pain or a feeling of fullness in the abdomen.

These symptoms and others may be caused by gastrointestinal carcinoid tumors or by other conditions. A doctor should be consulted if any of these symptoms occur.

Tests that examine the blood and urine are used to detect (find) and diagnose gastrointestinal carcinoid tumors.

The following tests and procedures may be used:

Complete blood count: A procedure in which a sample of blood is drawn and checked for the following:

• The number of red blood cells, white blood cells, and platelets.
• The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
• The portion of the sample made up of red blood cells.

Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient's health habits and past illnesses and treatments will also be taken.

Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances, such as hormones, released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that produces it. The blood sample is checked to see if it contains a hormone produced by carcinoid tumors. This test is used to help diagnose carcinoid syndrome.

Twenty-four-hour urine test: A test in which a urine sample is checked to measure the amounts of certain substances, such as hormones. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that produces it. The urine sample is checked to see if it contains a hormone produced by carcinoid tumors. This test is used to help diagnose carcinoid syndrome.

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis (chance of recovery) and treatment options depend on the following:

• Whether the cancer can be completely removed by surgery.
• Whether the cancer has spread from the stomach and intestines to other parts of the body, such as the liver or lymph nodes.
• The size of the tumor.
• Where the tumor is in the gastrointestinal tract.
• Whether the cancer is newly diagnosed or has recurred.

Treatment options also depend on whether the cancer is causing symptoms. Most gastrointestinal carcinoid tumors are slow-growing and can be treated and often cured. Even when not cured, many patients may live for a long time.

Stages of Gastrointestinal Carcinoid Tumors

After a gastrointestinal carcinoid tumor has been diagnosed, tests are done to find out if cancer cells have spread within the stomach and intestines or to other parts of the body.

Staging is the process used to find out how far the cancer has spread. The information gathered from the staging process determines the stage of the disease. There are no standard stages for gastrointestinal carcinoid tumors. In order to plan treatment, it is important to know the extent of the disease and whether the tumor can be removed by surgery. The following tests and procedures may be used:

Gastrointestinal endoscopy: A procedure to look inside the gastrointestinal tract for abnormal areas or cancer. An endoscope (a thin, lighted tube) is inserted through the mouth and esophagus into the stomach and first part of the small intestine. Also, a colonoscope (a thin, lighted tube) is inserted through the rectum into the colon (large intestine); this is called a colonoscopy.

CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.

Somatostatin receptor scintigraphy (SRS): A type of radionuclide scan used to find carcinoid tumors. In SRS, radioactive octreotide, a drug similar to somatostatin, is injected into a vein and travels through the bloodstream. The radioactive octreotide attaches to carcinoid tumor cells that have somatostatin receptors. A radiation-measuring device detects the radioactive material, showing where the carcinoid tumor cells are in the body. This procedure is also called an octreotide scan.

Biopsy: The removal of cells or tissues so they can be viewed under a microscope to check for signs of cancer. Tissue samples may be taken during endoscopy and colonoscopy.

Angiogram: A procedure to look at blood vessels and the flow of blood. A contrast dye is injected into the blood vessel. As the contrast dye moves through the blood vessel, x-rays are taken to see if there are any blockages.

PET scan (positron emission tomography scan): A procedure to find malignant tumor cells in the body. A small amount of radionuclide glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells.

X-ray of the abdomen: An x-ray of the organs and tissues inside the abdomen. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.

Gastrointestinal carcinoid tumors are grouped for treatment based on where they are in the body.

Localized

Cancer is found in the appendix, colon, rectum, small intestine, and/or stomach only.

Regional

Cancer has spread from the appendix, colon, rectum, stomach, and/or small intestine to nearby tissues or lymph nodes.

Metastatic

Cancer has spread to other parts of the body.

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