Carcinoid Tumors
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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.
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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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A recurrent gastrointestinal carcinoid tumor
is a tumor that has recurred (come back) after it has been treated. The tumor
may come back in the stomach or intestines or in other parts of the body.
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There are different types of treatment for patients with gastrointestinal
carcinoid tumors.
Different types of treatment are available for
patients with gastrointestinal carcinoid tumors. Some treatments are standard
(the currently used treatment), and some are being tested in clinical trials.
Before starting treatment, patients may want to think about taking part in
a clinical trial. A treatment clinical trial is a research study meant to
help improve current treatments or obtain information on new treatments for
patients with cancer. When clinical trials show that a new treatment is better
than the standard treatment, the new treatment may become the standard treatment.
Clinical trials are taking place in many parts
of the country. Choosing the most appropriate cancer treatment is a decision
that ideally involves the patient, family, and health care team.
Surgery
Treatment of gastrointestinal carcinoid tumors
usually includes surgery. One of the following surgical procedures may be
used:
- Appendectomy: Removal of the appendix.
- Fulguration: Use of an electric current to burn away the tumor using a
special tool.
- Cryosurgery: A treatment that uses an instrument to freeze and destroy
abnormal tissue, such as carcinoma in situ. This type of treatment is also
called cryotherapy. The doctor may use ultrasound to guide the instrument.
- Resection: Surgery to remove part or all of the organ that contains cancer.
Resection of the tumor and a small amount of normal tissue around it is
called a local excision.
- Bowel resection and anastomosis: Removal of the bowel tumor and a small
section of healthy bowel on each side. The healthy parts of the bowel are
then sewn together (anastomosis). Lymph nodes are removed and checked by
a pathologist to see if they contain cancer.
- Radiofrequency ablation: The use of a special probe with tiny electrodes
that release high-energy radio waves (similar to microwaves) that kill cancer
cells. The probe may be inserted through the skin or through an incision
(cut) in the abdomen.
- Hepatic resection: Surgery to remove part or all of the liver.
- Hepatic artery ligation or embolization: A procedure to ligate (tie off)
or embolize (block) the hepatic artery, the main blood vessel that brings
blood into the liver. Blocking the flow of blood to the liver helps kill
cancer cells growing there.
Radiation therapy
Radiation therapy is a cancer treatment that
uses high-energy x-rays or other types of radiation to kill cancer cells.
There are two types of radiation therapy. External radiation therapy uses
a machine outside the body to send radiation toward the cancer. Internal
radiation therapy uses a radioactive substance sealed in needles, seeds,
wires, or catheters that are placed directly into or near the cancer. The
way the radiation therapy is given depends on the type and stage of the cancer
being treated.
Chemotherapy
Chemotherapy is a cancer treatment that uses
drugs to stop the growth of cancer cells, either by killing the cells or
by stopping the cells from dividing. When chemotherapy is taken by mouth
or injected into a vein or muscle, the drugs enter the bloodstream and can
reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy
is placed directly into the spinal column, an organ, or a body cavity such
as the abdomen, the drugs mainly affect cancer cells in those areas (regional
chemotherapy).
Chemoembolization of the hepatic artery is
a type of regional chemotherapy that may be used to treat a gastrointestinal
carcinoid tumor that has spread to the liver. The anticancer drug is injected
into the hepatic artery through a catheter (thin tube). The drug is mixed
with a substance that embolizes (blocks) the artery, cutting off blood flow
to the tumor. Most of the anticancer drug is trapped near the tumor and only
a small amount of the drug reaches other parts of the body. The blockage
may be temporary or permanent, depending on the substance used to block the
artery. The tumor is prevented from getting the oxygen and nutrients it needs
to grow. The liver continues to receive blood from the hepatic portal vein,
which carries blood from the stomach and intestine.
The way the chemotherapy is given depends
on the type and stage of the cancer being treated.
Percutaneous ethanol injection is a cancer
treatment in which a small needle is used to inject ethanol (alcohol) directly
into a tumor to kill cancer cells. This procedure is also called intratumoral
ethanol injection.
Biologic therapy
Biologic therapy is a treatment that uses the
patient’s immune system to fight cancer. Substances made by the body or made
in a laboratory are used to boost, direct, or restore the body’s natural
defenses against cancer. This type of cancer treatment is also called biotherapy
or immunotherapy.
Hormone therapy
Hormone therapy is a cancer treatment that
removes hormones or blocks their action and stops cancer cells from growing.
Hormones are substances produced by glands in the body and circulated in
the bloodstream. The presence of some hormones can cause certain cancers
to grow. If tests show that the cancer cells have places where hormones can
attach (receptors), drugs, surgery, or radiation therapy are used to reduce
the production of hormones or block them from working.
Other drug therapy
MIBG (metaiodobenzylguanidine) is sometimes
used, with or without radioactive iodine (I131), to lessen the symptoms of gastrointestinal carcinoid tumors.
Other types of treatment are being tested in clinical trials.
Treatments being studied in clinical trials
for gastrointestinal carcinoid tumors include new combinations of chemotherapy.
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Carcinoid tumors in the appendix
Treatment of localized gastrointestinal carcinoid
tumors in the appendix may include the following:
- Appendectomy.
- Appendectomy and local excision.
- Appendectomy, bowel resection with anastomosis, and removal of lymph nodes.
Rectal carcinoid tumors
Treatment of localized gastrointestinal carcinoid
tumors in the rectum may include the following:
- Fulguration.
- Local excision.
- Resection.
Surgery that saves the sphincter muscles (the
muscles that open and close the anus) may be possible.
Small bowel carcinoid tumors
Treatment of localized gastrointestinal carcinoid
tumors in the small intestine may include the following:
- Local excision.
- Resection with removal of nearby lymph nodes.
Gastric, colon, and pancreatic carcinoid
tumors
Treatment of localized gastrointestinal carcinoid
tumors in the stomach, colon, or pancreas is usually resection.
Treatment is usually surgery to remove all
the cancer that can be seen at the site of the original tumor, as well as
nearby tissues and lymph nodes.
If the tumor cannot be completely removed
by surgery, treatment is usually palliative therapy to relieve symptoms and
improve the patient's quality of life. This may include the following:
- Resection, cryosurgery, or radiofrequency ablation to remove
as much of the tumor as possible.
- Chemoembolization to shrink tumors in the liver.
Distant metastases
If the metastatic gastrointestinal carcinoid
tumor is not causing symptoms, there may be a period of watchful waiting
before treatment is given. Treatment of distant metastases of gastrointestinal
carcinoid tumors is usually palliative therapy that may include the following:
- Surgery to bypass or remove part of a tumor blocking the small
intestine.
- Chemotherapy, which may include chemoembolization.
- Radiation therapy, sometimes with radioisotopes such as radioactive iodine (I131).
- MIBG (metaiodobenzylguanidine) therapy.
- Biologic therapy and/or hormone therapy.
- Clinical trials of new treatments.
Carcinoid syndrome
Treatment of metastatic gastrointestinal carcinoid
tumors that are causing carcinoid syndrome may include the following:
- Resection, cryosurgery, radiofrequency ablation, or percutaneous
ethanol injection for tumors in the liver.
- Hepatic artery ligation or embolization, with or without regional or systemic
chemotherapy.
- Hormone therapy.
- Biologic therapy with or without chemotherapy.
- Clinical trials of new combinations of chemotherapy.
A heart valve replacement may be done for
some patients with carcinoid syndrome.
Treatment of recurrent gastrointestinal carcinoid
tumors may include the following:
- Surgery to remove part or all of the tumor.
- A clinical trial.
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