Carcinoid Syndrome (cont.)
How are carcinoid tumors and carcinoid syndrome treated?
There are many options for the treatment of carcinoid tumors:
- observation
- surgery
- cryotherapy, radiofrequency ablation, hepatic artery
embolization
- interferon and chemotherapy
- radiation therapy
- medications for the
control of the carcinoid syndrome
Since carcinoid tumors vary widely in their size, malignant potential,
prognosis, extent of metastasis, and symptoms, treatment should be customized for
each individual. Because the carcinoid syndrome and metastatic carcinoid tumors
are rare and their treatments are complex, many patients should be treated by a
team of doctors--gastroenterologists, oncologists, radiologists, cardiologists,
and surgeons--in medical centers experienced and equipped to treat carcinoid
tumors.
Observation
Some patients with unresectable carcinoid tumors may have neither local
symptoms nor the carcinoid syndrome. These patients can be observed without
surgery or medications because carcinoid tumors are slow growing, and the
patients may not develop symptoms for a prolonged period of time.
Surgery
Surgery is used for 1) curative resection, 2) relief of
symptoms such as small intestinal obstruction or intestinal bleeding, and 3)
reducing the size of tumors that are not completely resectable, a process called tumor debulking, to
decrease the tumor burden and decrease the amount of hormone produced by the
tumors.
Small rectal carcinoid tumors usually are benign and often can be completely
excised for cure. Type 1 gastric carcinoid tumors also usually are benign and
often can be removed for cure. Small appendiceal carcinoid tumors usually are
removed and cured at the time of appendectomy.
Carcinoid tumors of the small intestine and the colon often are large and
have already metastasized at the time of diagnosis. Most patients with
metastases are not candidates for surgical cure because surgery cannot
completely remove the entire tumor. Occasionally, a patient may have a solitary
metastasis confined to a portion of the liver. Such patients can be treated with
surgical resection of the primary tumor and resection of that part of the liver
containing the tumor (partial hepatectomy). There are a limited number of
patients with multiple metastases that are confined to the liver. Partial
hepatectomy cannot be performed in these patients because of the multiple
locations of the tumors. A small number of these patients have been treated
successfully with liver transplantation.
Cryotherapy, radiofrequency
ablation, hepatic artery embolization
Cryotherapy, radiofrequency ablation , and hepatic artery embolization all are
techniques for debulking unresectable tumors (mainly liver metastasis) in order
to decrease tumor burden and to treat the carcinoid syndrome. Effective
debulking can improve the carcinoid syndrome and also prolong survival. Probes
that freeze (cryotherapy) or deliver radiofrequency waves (RF ablation) can be
inserted into the liver to debulk the liver of metastases from carcinoid tumors.
Hepatic artery embolization involves blocking the arterial blood supply to
carcinoid tumors (using oil-gelatin sponge particles) in the liver followed by
chemotherapy to debulk the remaining the liver tumors. Alternatively,
radioactive microspheres can be injected into hepatic arteries to kill the liver
tumors.
Interferon and chemotherapy
Interferon is a substance that inhibits the replication
of some viruses and the growth of some tumors. Interferon has been used to treat
patients with chronic hepatitis B and C. Interferon also has been
found to arrest the growth of carcinoid tumors in some patients. Interferon has
significant side effects,
however.
Chemotherapy has been used alone or in combinations with other therapies to
treat carcinoid tumors with metastases. The agents used include 5-fluorouracil (5-FU),
cyclophosphamide, streptozotocin, and doxorubicin. The tumors do not frequently
respond to treatment (a response is seen in under 30% of tumors), and the
duration of response usually is only a few months. The side effects and toxicity
of chemotherapy can be high.
Radiation therapy
External radiation has been used to alleviate pain due
to the presence of metastases from carcinoid tumors in the spine. It also may reduce the size of
the tumor in the spine. External radiation usually is not effective in treating
tumors within the liver.
Medications for the control of the carcinoid syndrome
The most important treatment modality for the carcinoid syndrome is
octreotide, a synthetic hormone similar in structure to the naturally-occurring
hormone, somatostatin. Somatostatin is widely distributed in the body where it
can inhibit the secretion of many other hormones including growth hormone,
insulin, and gastrin. It exerts its action by binding to specific receptors on
the membranes of cells that produce and release hormones and chemical
substances. Octreotide, like somatostatin, binds to receptors on the cells of
carcinoid tumors and inhibits the manufacture and release of tumor hormones.
Octreotide is very effective in controlling the symptoms of flushing and
diarrhea that are part of the carcinoid syndrome. Octreotide has been found to
reduce the excretion of 5-HIAA in some patients. Octreotide also has been found
to slow the growth of carcinoid tumors, and, in a few patients, even reduce the
size of the tumors and their metastases. Treatment with octreotide prior to
surgery is important in order to prevent life-threatening carcinoid crisis in
patients with carcinoid syndrome undergoing surgery. Some doctors are advocating
using octreotide even in patients without carcinoid syndrome to control the
growth of the carcinoid tumors.
Octreotide generally is well tolerated. Side effects include nausea,
headache, dizziness, abdominal
pain, diarrhea, elevated blood sugar levels, and gallstones. The major drawback of octreotide is the need to inject it under the
skin three times daily. Other longer-acting synthetic hormones resembling
somatostatin (for example, lanreotide) can be given intramuscularly every two
weeks, but they are not yet available in the U. S.
Patients with carcinoid syndrome should take vitamin
supplements, especially nicotinic acid, since carcinoid tumors can cause a
deficiency of nicotinic acid. In some patients, diarrhea caused by the carcinoid
syndrome may respond to Imodium, Lomotil, ondansetron (Zofran), or
cyproheptadine (Periactin). Patients also should avoid alcohol, spicy foods,
physical stress, and ephedrine-containing medications such as nasal
decongestants in order to avoid the precipitation of carcinoid syndrome by the
release of hormones and chemical substances from the tumor. Patients with
chronic diarrhea should take minerals supplements as well as vitamins since any cause of chronic diarrhea can lead to
deficiencies of minerals.
- Carcinoid tumors are rare tumors that develop from
hormone-producing cells called enterochromaffin cells that occur throughout
the body with approximately 65% originating in the gastrointestinal tract and
25% in the lungs.
- Carcinoid tumors can occur almost anywhere in the
gastrointestinal tract but primarily in the stomach, small intestine,
appendix, colon, and rectum.
- Carcinoid tumors can be benign or malignant.
- The carcinoid syndrome is a syndrome that is caused
by the release of hormones from carcinoid tumors, but only 10% of carcinoid
tumors cause the carcinoid syndrome.
- The carcinoid syndrome may include manifestations
such as abdominal pain, wheezing, facial flushing, diarrhea, heart disease,
and "carcinoid crisis."
- arcinoid tumors can be diagnosed by endoscopy, barium
small intestinal x-ray studies, and by capsule enteroscopy.
- Metastatic carcinoid tumors can be diagnosed by CT or
MRI scans, indium 111 octreotide scans, and bone scans.
- Carcinoid tumors can be managed with observation,
surgery, cryotherapy, radiofrequency ablation, hepatic artery embolization,
interferon therapy, chemotherapy, and radiation therapy.
- he carcinoid syndrome can be controlled with
medication.
Sources:
Stephen Goldfinger, MD "The Carcinoid Spectrum" in
Advances in Gastroenterology 2005 syllabus, Harvard Medical School Department of Continuing
Education
Thomas Anthony and Lawrence Kim, "Gastrointestinal Carcinoid Tumors and The
Carcinoid Syndrome" Sleisenger and Fordtran's Gastrointestinal and Liver
Disease, 7th Edition, Chapter 112, pages 2151-2168
Last Editorial Review: 7/26/2006
- interferon - Describes the medication interferon (Roferon-A, Intron-A, Rebetron, Alferon-N, Peg-Intron, Avonex, Betaseron, Infergen, Actimmune, Pegasys), a drug used in managing many diseases that involve the immune system.
- CT Scan (Computerized Axial Tomography) - CT Scan (Computerized Axial Tomography, CAT scan) is a procedure that assists in diagnosing tumors, fractures, bony structures, and infections in the organs and tissues of the body.
- Abdominal Pain - Learn about abdominal pain (pain in the stomach / abdomen) including causes, symptoms, how abdominal pain is diagnosed, and how abdominal pain is treated.
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