Carcinoid Tumors, Gastrointestinal

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Carcinoid tumors, gastrointestinal

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).

Diagnosis

If a patient has any abnormality that could be a symptom of a gastrointestinal carcinoid, the doctor asks about other symptoms that could be associated with carcinoid syndrome or caused by a tumor in the stomach, intestines, or rectum.

Diagnostic techniques

Doctors use a variety of diagnostic techniques to locate gastrointestinal carcinoids and determine how far the disease has spread:

barium enemas and x rays highlight abnormalities in the lining of the esophagus, stomach, and intestines
blood and urine tests measure amounts of substances that carcinoids secrete
colonoscopy provides a view of the entire length of the colon
endoscopic ultrasound shows how deeply tumors have penetrated the wall of the esophagus, stomach, intestines, or rectum and whether they have spread to nearby tissues
octreoscan detects the spread of gastrointestinal carcinoids by using a special camera to track the path of injected radioactive hormone-like substances that are attracted to these tumors

Provocative testing designed to cause the patient to flush can help doctors diagnose some gastrointestinal carcinoids, can provoke potentially serious reactions, and must be performed in a hospital, under close medical supervision.

Biopsy

Diagnostic tests can indicate that a patient has a gastrointestinal carcinoid, but only biopsy can confirm the diagnosis. Endoscopic biopsy is the most common way to remove a sample of a suspected gastrointestinal carcinoid.

A doctor performs this procedure by passing a flexible lighted tube topped with a tiny video camera (endoscope) down the patient's throat or up through the anus to examine the lining of the organs of the digestive tract. After locating a tumor, the doctor manipulates pincers or tongs (biopsy forceps) through the endoscope to remove a tissue sample.

Clinical staging, treatments, and prognosis

Staging

Doctors divide gastrointestinal carcinoids into three categories.

Localized cancer is found in the appendix, colon, rectum, small intestine, and stomach, but has not spread beyond the wall of the organ in which it originated.
Regional spread describes tumors that have penetrated the wall of the organ in which they originated and have involved nearby fat cells, ligaments, muscles, and lymph nodes.
Distant spread, or metastatic disease, refers to gastrointestinal carcinoids that have spread to the liver, bones, lungs, or other tissues or organs far from the original tumor.

Recurrent gastrointestinal carcinoid is disease that has returned after having been treated. Recurrent disease can develop at the site of the original tumor or in another part of the body.

Treatment

Treatment of gastrointestinal carcinoids is based on:

where the tumor originated
whether the cancer has spread beyond the gastrointestinal system
the patient's general health

Surgery

Surgery cures most gastrointestinal carcinoids. What type of operation a patient undergoes depends on the size and location of the tumor, whether the patient has serious disease of any other organ, and whether the tumor is causing carcinoid syndrome.

TREATING LOCALIZED GASTROINTESTINAL CARCINOIDS.

A surgeon can usually remove all of a tumor that has not spread (is localized). This procedure, called local excision, consists of removing the tumor and nearby normal tissue, and sewing together the affected ends of the remaining tissue.

If a carcinoid originates in the appendix, doctors usually remove the appendix (appendectomy). If the tumor is larger than 3/4" (cm) and the patient is under the age of 60 and otherwise in good health, the doctor may also remove the third of the colon closest to the appendix, and nearby blood vessels and lymph nodes.

When a carcinoid tumor originates in the small intestine, doctors usually remove part of the bowel, and may remove nearby lymph nodes to see if they contain cancer cells. Local excision is used to remove carcinoids that are not much larger than 3/8" (cm). Surgery for larger tumors removes a greater amount of normal surrounding tissue and some nearby blood vessels and lymph nodes.

Doctors usually treat localized carcinoids that originate in the stomach, pancreas, and colon by removing the affected organ.

Local excision is used to treat carcinoids that are limited to areas of the large intestine other than the appendix or to the rectum. Doctors use a flexible lighted instrument (colonoscope) to remove small tumors from these sites and remove larger tumors through an incision in the patient's abdomen.

Electrofulguration, a surgical procedure sometimes used to cure rectal carcinoids, destroys the tumor by heating it with electrical current. Doctors use electrofulguration to burn away rectal carcinoids no larger than 3/8" (cm). Tumors measuring 3/4" (cm) or more are apt to grow and metastasize and must be surgically removed.

Segmental colon resection (also called hemicolectomy) removes between one-third and one-half of the large intestine, and blood vessels and lymph nodes near the affected tissue.

Abdominoperineal resection is used for very large or very invasive carcinoids of the lower rectum. A patient who has this operation also has a colostomy . Deeply invasive rectal carcinoids that measure less than 3/4" are treated like larger tumors. Mildly invasive tumors of comparable size are treated with local excision and careful monitoring to check for recurrence.

Lower anterior resection is used for some carcinoids in the upper part of the rectum. This procedure removes some of the rectum before the remaining ends are sewn together, and has little lasting effect on the digestive system.

TREATING REGIONAL SPREAD.

When a gastrointestinal carcinoid has spread to organs or tissues close to the original tumor (regional spread), doctors usually remove the affected organ. Some nearby organs and tissues may also be removed.

If it is not possible to completely remove a gastrointestinal carcinoid that has spread to another part of the body, surgeons remove as much of the cancer as they can without damaging vital organs or causing severe side effects. Surgery cannot cure gastrointestinal carcinoids that have spread to parts of the body far from the original tumor, but it can relieve symptoms and slow the progression of the disease.

Liver resection removes one or more metastases (secondary tumors) from the liver. This procedure does not cure cancer but can relieve symptoms of carcinoid syndrome. Doctors destroy gastrointestinal carcinoids that have spread to the liver by:

using images generated by a CT scan (computed tomography scan) to guide a long thin needle into tumors and injecting them with concentrated alcohol
cooling the needle with liquid nitrogen to freeze carcinoid tumor cells (cryosurgery)

TREATING METASTATIC DISEASE.

Doctors treat gastrointestinal carcinoids that have spread to distant parts of the body by:

freezing and killing cancer cells
performing surgery or administering radiation or chemotherapy to relieve symptoms
using biological therapy to stimulate the patient's immune system to attack tumor cells

Neither radiation nor chemotherapy can cure gastrointestinal carcinoids. Doctors sometimes use external beam radiation to treat patients who are too ill or frail to withstand surgery, and to relieve pain caused by tumors that have spread to the bones.

Doctors may use several different chemotherapy drugs or combine a chemotherapy drug with other medication to slow tumor growth and relieve symptoms. Chemotherapy is generally used only for gastrointestinal carcinoids that have spread to other organs, cause severe symptoms, and have not responded to other treatments.

Doctors sometimes treat gastrointestinal carcinoids that have spread to the liver by injecting chemotherapy drugs directly into the artery that supplies blood to the liver (hepatic artery). This technique (intra-arterial chemotherapy):

exposes liver tumors to high doses of cancer-killing drugs
prevents side effects by shielding healthy tissues from these powerful medications

When doctors also inject material that blocks the hepatic artery, this treatment is called chemoembolization .

Octreotide is a hormone-like drug that can prevent or relieve flushing, wheezing, diarrhea, and other symptoms that sometimes occur during surgery or when gastrointestinal carcinoids release high levels of hormones. Octreotide can temporarily shrink these tumors but does not cure the cancer. Some patients experience pain at the site where the medication is injected, cramps, nausea and vomiting , dizziness, and fatigue .

Doctors also prescribe other medications to relieve specific symptoms.

Biological therapy, or Interferon-alpha therapy may stimulate the patient's immune system to attack the tumor, shrink metastatic gastrointestinal carcinoids, and may relieve symptoms of carcinoid syndrome. This technique, which is also called immunotherapy, is sometimes used to treat tumors that have not responded to chemotherapy or octreotide, but can cause severe flu-like side effects.

TREATING RECURRENT DISEASE.

Treatment of recurrent disease depends on where the new tumor is located and what treatment the patient has already received.

TREATING CARCINOID SYNDROME.

Treatments for carcinoid syndrome include surgically removing the cancer, blocking the hepatic artery or injecting chemotherapy drugs into it, medication to relieve symptoms, and stimulating the patient's immune system to attack the tumor.

LONG-TERM SURVEILLANCE.

After completing treatment, patients with certain types of gastrointestinal carcinoids must continue to have regular physical examinations, x rays, and blood and urine tests to help doctors detect recurrence during the earliest stages of disease.

Because some gastrointestinal carcinoids recur many years after initial treatment, high-risk patients should continue to see their doctor regularly. Any patient who has had a gastrointestinal carcinoid should immediately notify the doctor of any new symptoms. These symptoms could be side effects of treatment or a sign that the cancer has returned.

Prognosis

The only way to cure gastrointestinal carcinoids is to remove the tumors surgically. But because these cancers grow so slowly, it is not unusual for a patient to survive 10-15 years after being diagnosed with metastatic disease.

5-YEAR SURVIVAL RATES.

For patients whose carcinoid tumor originates in the stomach, the 5-year survival rate is:

64% for localized disease
40% for regional spread
10% for mestatatic disease

When tumors originate in the small intestine, the 5-year survival rate is:

65% for localized disease
66% for regional spread
36% for metastatic disease

For carcinoids that originate in parts of the colon other than the appendix, the 5-year survival rate is:

71% for localized disease
44% for regional spread
21% for metastatic disease

For carcinoids that originate in the appendix, the 5-year survival rate is:

94% for localized disease
85% for regional spread
34% for metastatic disease

For carcinoids that originate in the rectum, the 5-year survival rate is:

81% for localized disease
47% for regional spread
18% for metastatic disease

Having a gastrointestinal carcinoid increases a patient's risk of developing other cancers in the digestive system.

Clinical trials

Researchers are investigating:

how changes in cells transform normal tissues into gastrointestinal carcinoid tumors
how effectively specific chemotherapy drugs and surgical procedures treat gastrointestinal carcinoids
new ways of slowing or preventing growth of gastrointestinal carcinoids by blocking or shrinking the blood vessels that nourish them
how nuclear medicine can contribute to early detection of gastrointestinal carcinoids

Prevention

There is no known way to prevent gastrointestinal carcinoids or to reduce the risk of developing them, but avoiding the following can prevent symptoms of carcinoid syndrome from becoming more intense:

alcoholic drinks
hot, spicy foods
strenuous exercise
stress

See Also Cryotherapy; Gastrointestinal cancers; Hepatic arterial infusion; Neuroendocrine tumors

Resources

BOOKS

Goldman, Lee and J. Claude Bennett. Cecil Textbook of Medicine, 21st ed., vol, 2. Philadelphia, PA: W.B.Saunders Company, 2000.

ORGANIZATIONS

National Carcinoid Support Group, Inc. 6666 Odana Rd., #146, Madison, WI 53719-1012. <http://members.aol.com/thencsg/info.html>

OTHER

"Gastrointestinal Carcinoid Tumor." CancerNet. November 2000. 31 March 2001 <http://cancernet.nci.nih.gov>.

"Gastrointestinal Carcinoid Tumors." Gastrointestinal Carcinoid Tumors Resource Center. 12 February 1999. April 2001 <http://www3.cancer.org>

"Carcinoid May Be Rare—But If You have It, You Are Not Alone." National Carcinoid Suport Group. 15 May 1999. 31 March 2001 <http://members.aol.com/thencsg>

"Carcinoid Research:There Is Hope." National Carcinoid Support Group 31 March 2001 <http://members.aol.com/thencsg>.

"Carcinoid Treatment:More Than One Option to Consider."National Carcinoid Support Group. 31 March 2001 <http://members.aol.com/thencsg/treatment.html>.

National Carcinoid Support Group Questions & Answers About Carcinoid 31 March 2001<http://members.aol.com/thencsg/info.html>.

Maureen Haggerty

KEY TERMS

Adrenal gland

—Either of two glands that secrete hormones that maintain the balance of water and salt in the body and regulate the functions of other organs. Also called suprarenal glands.