- Carcinoid tumors are fairly rare
cancers that can occur most commonly in the intestine and
- Carcinoid tumors are not very common. These cancers arise from cells in the body that produce certain hormones. Carcinoid tumors most often develop in the intestine or lungs. In some cases, the cancers cause symptoms such as bleeding, pain, and Intestinal Obstruction because of their size and location. In other cases, symptoms such as flushing, Diarrhea, and Low Blood Pressure
are caused by the release of large amounts of hormones by
these cancers. However, these symptoms usually do not occur
until the cancer has spread to the liver. Carcinoid tumors
can develop anywhere within the intestinal tract (from the
stomach to the rectum). They are most often found in the
appendix. Far less frequently, they develop outside the
intestinal tract, with the most common site being the lungs.
The treatment for this disease depends on the size and
location. If the tumor is small and has not spread to other
parts, then it can often be surgically removed. Once the
tumor has spread to the liver, treatment is primarily aimed
at decreasing symptoms. Long-term prognosis depends on
whether or not the cancer has spread to the lymph nodes or
- For more details regarding Carcinoid Syndrome, please see the section "Carcinoid Syndrome."
- Carcinoid tumors often do not cause
any significant symptoms until late in the disease process.
That is, they grow slowly and do not cause any problems for
a long time. In fact, because they are slow growing and
often cause only vague symptoms, the average time between
onset of symptoms and diagnosis is 4 to 5 years.
- Symptoms that can be caused by intestinal carcinoid tumors include gastrointestinal bleeding, bowel obstruction, Intussusception, or
abdominal pain, depending on their location and size.
However, these symptoms can also be due to many other
- Also, in some cases, the cancer
spreads to the abdominal cavity and triggers a reaction that
causes the lining of the abdomen to become very thick and
hard. This can also cause bowel obstruction and stomach
- Other symptoms include nausea,
fatigue, and weight loss.
- If the cancer spreads to the liver, then one can develop Carcinoid Syndrome, which is caused by hormones released from the cancer cells. The symptoms include flushing, Diarrhea, Low Blood Pressure, wheezing, and sometimes problems with the heart valves. For more details, see the section on Carcinoid Syndrome.
- People with bronchial carcinoid tumors (these are carcinoid tumors that develop in the lungs) usually have wheezing, frequent Pneumonias, and a
cough (including coughing blood). If the cancer blocks one
of the air passages, then one may feel short of breath.
- In a few cases of bronchial
carcinoid tumors, the cancer is located in the very outer
part of the lungs and may not cause any symptoms at all.
- People with pulmonary carcinoid tumors usually do not have the symptoms associated with Carcinoid Syndrome
because these tumors grow slowly and only rarely metastasize
(or spread) to the
- The cause of carcinoid tumors is
not known. They develop because of the uncontrolled
replication of certain cells. However, what causes this
abnormal growth is not known.
- 90% of all carcinoid tumors develop
in the intestinal tract. They can develop almost anywhere
throughout the intestinal tract, all the way from the
stomach to the rectum. The most common locations are the
appendix, intestine, and stomach.
- Another common location for
carcinoid tumors is the lung. These tumors usually occur in
men and women equally and most people with the cancer are
less than 60 years old.
- Other less common sites for the
development of carcinoid tumors include the thymus, bile
ducts, breast, and ovary. Also, carcinoid tumors are
sometimes a part of the MEN (multiple endocrine neoplasia)
Type I syndrome.
- Approximately half of all carcinoid
tumors develop in the appendix. Cancers that develop in this
location are usually benign. They may spread locally, but
rarely do they spread to distant sites.
- Rectal carcinoid tumors (carcinoid
tumors that develop in the rectum) are also usually benign.
- However, carcinoid tumors that
develop in the small intestine are usually more malignant.
They have a higher tendency to spread both locally as well
as to metastasize to other parts of the body, including the
- Carcinoid tumors that develop in
the lungs are potentially malignant and can spread locally
as well as to distant sites. However, they are considered to
be less aggressive than tumors that develop in the small
- Carcinoid tumors usually spread to
the lymph nodes and liver. However, they can also spread to
the bone, heart, breast, or eye.
- Carcinoid tumors that develop in the thymus may be associated with Hyperparathyroidism
or with Cushing's syndrome.
- The chance of metastasis depends on
the size of the tumor. If it is smaller than 1 cm, then it
rarely metastasizes. If it is bigger than 2 cm, then almost
100% of the time it has spread.
- As stated above, diagnosis is often delayed several years because the symptoms can initially be vague. Also, the characteristic symptoms of Carcinoid Syndrome
only occur after the cancer has spread to the liver.
- Once the diagnosis is suspected,
several tests can be done. Certain tests can be done to
identify the location of the tumors.
- Endoscopy - in this test a camera
is used to look into the stomach and the first part of the
intestine, or it can be used to look at the large
intestine. This test can also be used to do biopsies (in
which a piece of the tumor is removed so that it can be
analyzed in the laboratory).
- CT scan - this test can help
identify larger tumors and can also see if there is any
spread to the liver.
- Barium studies - in this test a dye is administered and X-Rays are taken of
the intestinal tract. This may help identify tumors.
- In addition to CT scan, abdominal Ultrasound and Angiography (in which
a dye is injected into blood vessels) can be used to see if
the cancer has spread to the liver.
- A nuclear medicine scan can also be
done if all else fails. This test uses a substance that is
absorbed by carcinoid tumor cells. With this test you can
see any areas that take up large amounts of the substance.
- Bronchial carcinoids can be diagnosed by Bronchoscopy (in
which a camera is inserted into the lungs) or by CT scan.
- In almost all cases, even though cancer is suspected, the only way to confirm the diagnosis is by performing a biopsy. For cancers within the intestinal tract, biopsies can be done with endoscopy. For cancers that have spread to the liver, a Liver biopsy can be done. For cancers in the lung, a biopsy can be done by either Bronchoscopy or by a
- If one has symptoms of Carcinoid Syndrome,
then blood and urine tests for 5-HIAA (5-hyroxyindolacetic
acid) can be done. Carcinoid tumors secret a substance known
as serotonin. This substance is then converted to 5-HIAA and
excreted in the urine.
- Since most people with Carcinoid Syndrome
will have an elevated urine 5-HIAA level, this the most
- Some people with Carcinoid Syndrome
may have normal urinary 5-HIAA levels. In these cases, they
may need to have their blood serotonin levels measured to
make the diagnosis.
- Also, in some cases of gastric
carcinoid tumors, very little 5-HIAA is formed. Therefore,
other lab tests such as 5-HTP levels, urine serotonin
levels, or histamine levels may need to be checked.
- Sometimes, the diagnosis is
unclear, as when the patient complains of flushing but the
doctor has not seen it. In such cases, medicines, such as
alcohol, pentagastrin, or extremely low doses of epinephrine
can be given to cause flushing.
- Bananas, plantains, pineapples,
kiwi fruits, walnuts, plums, pecans, avocados, guaifenesin,
and acetaminophen can elevate 5-HIAA levels. Aspirin and
levodopa can decrease 5-HIAA levels. Therefore, these
variables must be taken into account when checking 5-HIAA
- There are no definite risk factors
for the development of carcinoid tumors.
- However, certain conditions such as Hashimoto's Thyroiditis, MEN (multiple endocrine neoplasia)
syndrome Type I, pernicious anemia, and achlorhydria all are
associated with a higher chance of developing carcinoid
- Treatment depends on whether or not Carcinoid Syndrome is
present and the severity of the symptoms.
- Because most people with Carcinoid Syndrome
have metastatic disease to the liver, surgery is not really
- If symptoms are not too severe, they can be controlled
with certain medications.
- For Diarrhea, medicines
such as loperamide, diphenoxylate/atropine,
cyproheptadine, or methysergide can be used.
- For flushing, treatment is given if the symptoms are
frequent or severe. Medications that can be used include
anti-histamines (such as diphenhydramine) along with
anti-ulcer medications (such as ranitidine). These two
medicines in combination can help reduce the flushing.
- Another medicine called phenoxybenzamine can also be
used to help reduce the flushing.
- People with wheezing and trouble breathing caused by
lung carcinoids can be treated with steroids and medicines
such as theophylline. Inhalers such as albuterol should be
avoided because they can make the symptoms worse.
- One of the most effective drugs used in treating people with Carcinoid Syndrome is octreotide. It can reduce the wheezing, flushing, and Diarrhea associated with the disease in over 75% of the people. It can also be used to treat the Low Blood Pressure
that can sometimes occur with this disease. It does not
treat any heart valve problems associated with the disease
and it is not clear whether it decreases the fibrosis
caused by the disease. The other problem with octreotide
is that it has to be given either intravenously or by
injections several times a day.
- Surgical removal of the cancer is the best treatment for
tumors from the appendix or large intestine that are less
than 2 centimeters in size.
- Carcinoid tumors from other parts of the intestinal
tract are also surgically removed if the cancer has not
spread. However, remember, the diagnosis of carcinoid tumors
is usually delayed. The vast majority of people have liver
involvement by the time the diagnosis is made. In a few
cases where only one metastatic lesion is found in the
liver, removal of the cancer and the metastatic liver lesion
results in some improvement of survival. However, in the
majority of cases, surgery may temporarily reduce symptoms,
but does not change the long-term outlook. Thus, in most
cases, surgery is usually not performed for intestinal
- In some people with Carcinoid Syndrome
due to a tumor in the lung or other site outside the
intestine, they may be cured if the tumor is removed.
- There are also other treatments that have been tried for
carcinoid tumors. The problem is that these cancers
generally do not respond to chemotherapy or to radiation
therapy. Therefore, these are not very good options.
- Certain therapies do reduce the size of the tumor as
well as the symptoms. However, these treatments do not
really change the long-term prognosis. These
- Hepatic artery embolization - in this procedure, the blood supply to the tumor is cut off by blocking the artery. In 90% of people, this will reduce the symptoms temporarily. Complications of this treatment include pain, fever, and problems with liver function. Also, symptoms of Carcinoid Syndrome
may increase temporarily after the procedure.
- Local radiation therapy - this is often not very
effective because these tumors are often resistant to
- Selective hepatic artery chemotherapy infusion - in
this procedure, an angiogram is performed to see which
artery is feeding the cancer. Then, chemotherapy is given
into that specific artery in an attempt to destroy the
cancer. However, as mentioned above, carcinoid tumors are
often very resistant to chemotherapy.
- Newer treatments are being studied. Hopefully, research
will result in more options in the future.
- In some people with bronchial carcinoid tumors as well as carcinoid tumors outside the intestinal tract, surgical removal is an option even if they have Carcinoid Syndrome.
Radiation therapy and chemotherapy are not options because
these treatments usually do not work. .
- In a few cases of bronchial carcinoid tumors, no
treatment is needed. They can simply be followed with serial
- The long-term outlook depends on the area where the
cancer develops, the size of the cancer, and whether or not
it has metastasized.
- Carcinoid tumors that develop in the appendix or rectum
are usually very slow growing and rarely affect long-term
- For carcinoids that develop in other parts of the
intestine or stomach, the 5-year survival is 95% if it has
not spread, 65% if it has only spread to the local lymph
nodes, and about 20% if it has metastasized to the liver.
- Once the person has developed flushing, survival on
average is about 2 to 3 years. Also, the higher the urine
5-HIAA levels, the worse the prognosis.
- If the tumor spreads to the liver, then it can lead to Carcinoid Syndrome
and its associated complications.
- Bronchial carcinoid usually does
not invade locally or metastasize. Complications are usually
from bleeding and from airway obstruction.
- Other complications from intestinal carcinoid tumors include abdominal pain, intestinal bleeding, Intestinal Obstruction, bowel infarction, or Intussusception. Also
the cancer can spread to the lining of the intestine and
cause it to become thick and hard (fibrotic).
- There is really no way to prevent
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