Key Points for This Section

A gastrointestinal carcinoid tumor is cancer that forms in the lining of the gastrointestinal tract. Health history can affect the risk of developing gastrointestinal carcinoid tumors. 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. Tests that examine the blood and urine are used to detect (find) and diagnose gastrointestinal carcinoid tumors. Certain factors affect prognosis (chance of recovery) and treatment options.

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.

Glossary Terms

The area of the body that contains the pancreas, stomach, intestines, liver, gallbladder, and other organs.

A small, fingerlike pouch that sticks out from the cecum (the first part of the large intestine near the end of the small intestine).

A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.

A procedure in which a sample of blood is examined to measure the amounts of certain substances made in the body. An abnormal amount of a substance can be a sign of disease in the organ or tissue that produces it.

A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord.

A sugar molecule. Carbohydrates can be small and simple (for example, glucose) or they can be large and complex (for example, polysaccharides such as starch, chitin or cellulose).

A slow-growing type of tumor usually found in the gastrointestinal system (most often in the appendix), and sometimes in the lungs or other sites. Carcinoid tumors may spread to the liver or other sites in the body, and they may secrete substances such as serotonin or prostaglandins, causing carcinoid syndrome.

A combination of symptoms caused by the release of serotonin and other substances from carcinoid tumors of the gastrointestinal tract. Symptoms may include flushing of the face, flat angiomas (small collections of dilated blood vessels) of the skin, diarrhea, bronchial spasms, rapid pulse, and sudden drops in blood pressure.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

A test to check the number of red blood cells, white blood cells, and platelets in a sample of blood. Also called blood cell count and CBC.

The process of identifying a disease, such as cancer, from its signs and symptoms.

Frequent and watery bowel movements.

The organs that take in food and turn it into products that the body can use to stay healthy. Waste products the body cannot use leave the body through bowel movements. The digestive system includes the salivary glands, mouth, esophagus, stomach, liver, pancreas, gallbladder, small and large intestines, and rectum.

A protein that speeds up chemical reactions in the body.

Inflammation of the lining of the stomach.

The stomach and intestines. The gastrointestinal tract is part of the digestive system, which also includes the salivary glands, mouth, esophagus, liver, pancreas, gallbladder, and rectum.

The substance inside red blood cells that binds to oxygen in the lungs and carries it to the tissues.

One of many chemicals made by glands in the body. Hormones circulate in the bloodstream and control the actions of certain cells or organs. Some hormones can also be made in the laboratory.

The long, tube-like organ that is connected to the small intestine at one end and the anus at the other. The large intestine has four parts: cecum, colon, rectum, and anal canal. Partly digested food moves through the cecum into the colon, where water and some nutrients and electrolytes are removed. The remaining material, solid waste called stool, moves through the colon, is stored in the rectum, and leaves the body through the anal canal and anus.

A large organ located in the upper abdomen. The liver cleanses the blood and aids in digestion by secreting bile.

In medicine, a mineral is a nutrient that is needed in small amounts to keep the body healthy. Mineral nutrients include the elements calcium, magnesium, and iron.

A rare, inherited disorder that affects the endocrine glands and can cause tumors in the parathyroid and pituitary glands and the pancreas. These tumors (usually benign) cause the glands to secrete high levels of hormones, which can lead to other medical problems, such as kidney stones, fertility problems, and severe ulcers. In some cases, tumors inside the pancreas can become cancerous. Also called MEN1 syndrome, multiple endocrine adenomatosis, and Wermer syndrome.

A chemical compound (such as protein, fat, carbohydrate, vitamin, or mineral) contained in foods. These compounds are used by the body to function and grow.

A part of the body that performs a specific function. For example, the heart is an organ.

A type of anemia (low red blood cell count) caused by the body's inability to absorb vitamin B12.

An exam of the body to check for general signs of disease.

A type of blood cell that helps prevent bleeding by causing blood clots to form. Also called thrombocyte.

The likely outcome or course of a disease; the chance of recovery or recurrence.

A molecule made up of amino acids that are needed for the body to function properly. Proteins are the basis of body structures such as skin and hair and of substances such as enzymes, cytokines, and antibodies.

The last several inches of the large intestine closest to the anus.

To come back or to return.

A cell that carries oxygen to all parts of the body. Also called erythrocyte and RBC.

Something that may increase the chance of developing a disease. Some examples of risk factors for cancer include age, a family history of certain cancers, use of tobacco products, certain eating habits, obesity, lack of exercise, exposure to radiation or other cancer-causing agents, and certain genetic changes.

The part of the digestive tract that is located between the stomach and the large intestine.

An organ that is part of the digestive system. The stomach helps digest food by mixing it with digestive juices and churning it into a thin liquid.

A procedure to remove or repair a part of the body or to find out whether disease is present. An operation.

An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.

A group or layer of cells that work together to perform a specific function.

An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancerous), or malignant (cancerous). Also called neoplasm.

Fluid containing water and waste products. Urine is made by the kidneys, stored in the bladder, and leaves the body through the urethra.

A nutrient that the body needs in small amounts to function and stay healthy. Sources of vitamins are plant and animal food products and dietary supplements. Some vitamins are made in the human body from food products. Vitamins are either fat-soluble (can dissolve in fats and oils) or water-soluble (can dissolve in water). Excess fat-soluble vitamins are stored in the body’s fatty tissue, but excess water-soluble vitamins are removed in the urine. Examples are vitamin A, vitamin C, and vitamin E.

Refers to a blood cell that does not contain hemoglobin. White blood cells include lymphocytes, neutrophils, eosinophils, macrophages, and mast cells. These cells are made by bone marrow and help the body fight infections and other diseases. Also called WBC.

A disorder in which tumors of the pancreatic islet cells produce large amounts of gastrin (a hormone), leading to excess acid in the stomach and, possibly, a peptic ulcer (ulcer of the stomach or the upper part of the small intestine).