Carcinoid Tumors, Gastrointes... Health Article

Definition

Gastrointestinal carcinoid tumors are rare malignancies in which cancer develops in hormone-producing cells that line the appendix, bronchus, esophagus, intestines, liver, ovary, pancreas, rectum, stomach, testes, and thymus.

Description

Gastrointestinal carcinoid tumors are also called:

• carcinoids
• endocrine tumors, carcinoid type
• metastatic carcinoid tumors
• neuroendocrine tumors
• neuroendocrine cancers

Types of gastrointestinal carcinoids

Doctors describe gastrointestinal carcinoids according to the part of the gastrointestinal tract in which they originate. Foregut tumors start in the cells of the esophagus, bronchus, thymus, and stomach.

Midgut tumors originate in the: appendix, liver, ovary, small intestine, and parts of the large intestine.

Hindgut tumors originate in the rest of the colon or in the rectum.

About 75% of all carcinoid tumors originate in the digestive system. Most of them develop in the:

• small intestine (ileum)
• appendix
• rectum

Atypical tumor behavior

Most cancers cause symptoms in the organs in which they start or to which they spread (metastasize), but carcinoids can release chemicals (hormones) that travel through the bloodstream and cause symptoms in many parts of the body. These substances can damage heart valves, causing weakness, heart murmur, and shortness of breath.

Some gastrointestinal carcinoids stimulate the adrenal glands to produce abnormally high levels of the hormones that regulate the balance of water and salt in the body. Overproduction of these hormones causes weakness, weight gain, secondary diabetes, and excessive facial and body hair.

Carcinoid syndrome

Although gastrointestinal carcinoids behave differently in different people, tumors that originate in the appendix don't usually spread to other organs. Tumors that develop in the colon or rectum hardly ever produce hormones. Tumors that originate in the small intestine or other parts of the gastrointestinal tract and spread to the liver generally cause carcinoid syndrome. Flushing of the face and neck is the most common symptom of this rare malignant disease that affects the small intestine, stomach, and pancreas, and fewer than 10% of patients with gastrointestinal carcinoids.

Carcinoid syndrome is also characterized by:

• abdominal cramps
• breathlessness
• cyanosis
• diarrhea
• rapid heart beat (tachycardia)
• swelling around the eyes
• tearing
• wheezing

Stress, strenuous exercise, eating spicy foods, or drinking alcohol can intensify these symptoms.

Disease progression

Gastrointestinal carcinoids originate as small growths called tumorlets. These miniature tumors grow very slowly and few of them develop into carcinoid tumors.

The hormones that gastrointestinal carcinoids release generally cause more problems than the tumors themselves. Death usually results from heart or liver failure or from complications associated with tumor growth.

Demographics

About 2, 500 carcinoids are diagnosed in the United States every year. African Americans develop carcinoids more often than Caucasians, and African-American women develop them more often than African-American men. Caucasian men and women are equally likely to develop these tumors.

The average age of patients diagnosed with carcinoid tumor of the appendix is 40. The average age of patients diagosed with carcinoid tumor of the stomach, small intestine, colon, and rectum is 55-65.

Causes and symptoms

The cause of gastrointestinal carcinoids is unknown, some risk factors have been identified. The risk factors that increase a person's risk of developing gastrointestinal carcinoids include:

• Having certain diseases that damage the stomach and decrease production of stomach acid. (Some of these diseases include chronic atrophic gastritis associated with pernicious anemia, chronic gastric infection with the H. pylori bacteria, auto-immune gastritis, or AIDS.)
• Having a family history of multiple endocrine neoplasia, type 1. (The multiple endocrine neoplasia (MEN) syndromes are three related disorders in which two or more of the hormone-secreting (endocrine) glands of the body develop tumors. Commonly affected glands are the thyroid, parathyroids, pituitary, adrenals, and pancreas. Patients diagnosed with this syndrome are at a higher risk for developing a variety of cancers, and require more frequent monitoring than the average patient might.)

Symptoms

Early-stage gastrointestinal carcinoids rarely cause symptoms. About half of these tumors are discovered during tests or surgical procedures performed to diagnose or treat other diseases of the digestive system.

The most common early symptom of gastrointestinal carcinoids is uncomfortable flushing of the face and neck. Most people who have gastrointestinal carcinoids eventually experience:

• abdominal cramps
• changes in bowel habits
• other symptoms similar to those of other intestinal cancers

Some gastrointestinal carcinoids cause:

• intestinal bleeding
• asthmatic wheezing
• impotence
• loss of interest in sex (libido)

Most patients develop abnormal connective tissue on the right side of the heart (endocardial fibrosis).