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The digestive system comprises
of the oral cavity, the food pipe, the stomach, the
small and large intestine and the various associated
glands, which help in digesting food.
The digestive system helps provide nutrition to the body by absorbing
vitamins, minerals, carbohydrates, fats, proteins
and water from the food that is eaten and filters
out the waste until the body eliminates it.
The final 6 feet of the intestine is known as the large intestine or
the colon. The last 10 inches of the colon is known
as the rectum. The appendix
or the vermiform appendix is a small tubular organ with a blind end,
which is located along the wall of the cecum, which is the first most
capacious part of the large intestine. The cecum is joined at one end
to the ileum through a one-way valve system, which
is called the iliocecal valve, and this cecum then
carries on superiorly and distally as the ascending
colon or the ascending large intestine.
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| The Digestive System |
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What is Gastrointestinal Carcinoid tumour?
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These are very uncommon
and unusual tumors, which are found in certain hormone making
cells of the digestive or gastrointestinal system.
The cells which produce carcinoid tumors are known as the APUD
cells (amine precursor uptake and decarboxylation). These
are special cells found in various pockets along the lining of
the gastrointestinal tract or the digestive tract, which serve
hormonal functions in order to allow the gut to function properly.
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How does a Gastrointestinal Carcinoid tumour present?
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In most cases,
they are totally asymptomatic.
Sometimes, the tumour may produce an excess amount of hormones
and the patient may present with symptomatology because of excessive
hormone production. Such a condition is known as a paraneoplastic
syndrome, because the condition is not directly produced by
the tumour itself but by the hormones, which are being over-produced
by the tumour.
The effect of the hormones could result in: |
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Pain in the abdomen. |
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Flushing and swelling
of the skin on the face and neck. |
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Intractable diarrhea. |
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Symptoms of heart failure. |
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Breathlessness. |
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Wheezing. |
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carcinoid may produce signs and symptoms of a lump in the abdomen and direct symptomatology due to a mass present
in the digestive system. |
Sometimes,
the carcinoid may cause obstruction of the vermiform appendix,
resulting in an attack of appendicitis very
early on; the patient is opened up keeping the diagnosis of appendicitis
in mind, an appendicectomy is performed, and it is found, fortunately,
for the patient, that it was a very early carcinoid tumour which
presented in this way. However, this kind of presentation as described
last is very opportune and is rarely encountered.
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How are Gastrointestinal Carcinoid tumors detected?
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Besides the
routine investigations, the doctor may order special blood and
urine tests to find out what byproducts or metabolites
as they are known as, of the hormones, are produced by the tumour.
The doctor may also order several imaging investigations including
a barium meal follow-through or a small
bowel enema, or a barium
enema.
A barium meal follow-through is an investigation
in which the person is asked to swallow fluid containing barium
sulphate and when the barium passes into the small bowel, pictures
are taken radiologically to find out what is the status of the
lining of the small bowel.
A barium enema is when the same fluid with
barium contained in it is introduced through the anal canal and
rectum and is pushed in the form of an enema (in a retrograde
manner or backward manner)so that it fills the entire large bowel
and may perforce fill the cecum and the appendix as well. The
pictures are then taken radiologically to find out if there are
any abnormalities in this area.
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What are staging and grading?
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These are
terms with which you must become familiar, if you are dealing
with any form of cancer.
When we stage
a cancer, we try to establish carefully degree of spread of the
cancer and if indeed there is spread, to what extent and involving
which organs.
The grading
of a cancer is a microscopic issue, in which the pathologist lets
you know how aggressive this particular type of cancer is; well
differentiated means less aggressive, moderately
differentiated intermediately aggressive and poorly
differentiated more aggressive.
Both grading and staging help your clinician to establish the
prognosis
or how serious your disease is and what is going to be the likely
outcome.
Staging may require additional imaging tests such as CT
Scan, MRI, Sonography of the abdomen, Bone scan or chest X-ray.
For various practical purposes, the simple staging given below
is informative for the public.
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Localized.
The cancer is found only in the appendix, the colon or the
rectum, the small intestine or stomach, but does not spread to
the other parts of the body.
One small mention here: Although the carcinoid is a tumour, which
is found most commonly in the vermiform appendix, it may be located
anywhere along the gastrointestinal tract, and may present in
other foci on the body as well). |
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One small
mention here: Although the carcinoid is a tumor, which is
found most commonly in the vermiform appendix, it may be located
anywhere along the gastrointestinal tract, and may present in
other foci in the body as well. |
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Regional.
Cancer has spread from the appendix, colon or rectum, small
intestine or stomach to adjacent tissues or lymph
nodes (Lymph nodes are small bean-shaped structures, which
act as stations for drainage of lymph, a clear watery fluid, which
courses through out the body in transparent, thin tubes called
lymph channels or lymphatics,
from various organs). |
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Metastatic.
It has spread to various different parts of the body. |
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Recurrent.
This is a disease which has come back after the primary therapy
for the carcinoid is over. It may recur in the original focus
itself or in other parts of the body.
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How are Gastrointestinal Carcinoid tumors treated?
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A lot depends
on the patient's constitution, the grade of his disease and its
staging. Patients are usually treated by a team of specialists
which utilizes a multipronged approach. This includes an an oncosurgeon
and a radiotherapist. The plan of treatment is tailored to fit
a patient's requirements. If necessary, biological therapy and
chemotherapy may become an add ons.
Treatment strategies
The bastions of treatment for gastrointestinal carcinoid tumors
are surgery, radiation and surgery and radiation.
The surgical procedure which is to be undertaken
primarily depends on the location of the tumour and the degree
of advancement of the lesion.
If the cancer has just about started, then a simple appendicectomy
or removal of the appendix is good enough.
If the carcinoid is found to be a little more aggressive and the
x-rays depict it to be so, then a section of the large intestine
and a small portion of the small intestine may be removed, and
the remaining portions of the small and large intestines are joined
together. This procedure is known as a hemicolectomy.
If lymph nodes are also removed during this procedure and a leaf
of the tissue joining the intestine known as the mesocolon is
also removed along with the colon sample (which is also larger
in size as compared to standard colon resected), then this procedure
is known as a radical hemicolectomy.
A local excision, which is less than a hemicolectomy,
using a special instrument inserted into the colon or rectum up
to the anus to cut the tumour out can be used. This is an endoscopic
procedure in which a fibre optic, flexible, thin tube called
a colonoscope is introduced into the anal
verge and is pushed up into the rectum, ascending colon and into
the cecum and it has got a small port or channel through which
small tumors can be excised. This is a procedure which is recommended
only for very, very small tumors.
Using the endoscopic tube again, we can burn the tumour using
an electric current or a diathermy. As far
as hemicolectomy is concerned, one must make sure that there is
a reasonable margin of healthy tissue taken out along with the
tumour cells in order to give the patient the maximum chances
of cure.
Endoscopically, another type of instrument called a cryoprobe
can be introduced through the colonoscope. The cryoprobe is an
instrument which produces extreme freezing in the area it touches.
If its brought in contact with the cancer, greater strength is
used to freeze the cancer completely and to kill it.
If it is found that the disease has metastasized
or spread to the liver, then hepatic artery ligation
is one procedure which can be performed, in which the hepatic
artery, which is one of the main blood vessels supplying blood
to the liver, is ligated or tied off. This cuts off the blood
supply to the tumour area and decreases the vascularity of the
tumour, thus killing the metastasis.
The other procedure, which can be performed is a hepatic
artery embolization in which either drugs or other agents
such as gel foams, coils, wire loops, etc.
can be introduced into the hepatic artery. These then reduce or
block the flow of the blood to the liver and the sections where
the tumour is lodged, in order to kill the cancer cells from growing
progressively in the liver.
The alternative local therapy to surgery is radiation
therapy. This involves the use of high energy, penetrative
rays to destroy cancer cells. It affects cancer cells only in
the zone treated. Radiation therapy is also employed for palliation
i.e. control of symptoms alone in an advanced cancer.
Radiation therapy can also be used in adjunct to surgery or chemotherapy,
either before or after.
Teletherapy or external
radiation is given via a machine remote from the body while brachytherapy
or internal radiation is given by implanting a radioactive source
within the involved tissues. Patients may or may not require both
modalities of radiation.
Radiotherapy, after initial planning, usually takes just 5 to
10 minutes per day, 5 days a week for about 6 weeks. This time
period is flexible depending upon the modality of radiation used.
Besides local therapy, the best attempt to control cancer cells
circulating in the body and lodged at places other than the original
carcinoid focus is by using systemic
therapy (therapy which affects the
entire systems of the body) which is in the form of injections
or oral drugs. This form of treatment is called chemotherapy.
This form of treatment is given in a cyclical manner (each set
of drugs is repeated usually after every 3-4 weeks).
Chemotherapy can also be used in combination with surgery, radiotherapy
or both, either before or after.
Biological therapy
employs Biological
Response Modifiers (BRM's), which are substances that
use the body's own immune system, either directly or indirectly,
to fight cancer or to lessen the side effects of the anti cancer
drugs. Some examples of BRM's are interferon-alfa
and interleukin-2.
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What are the side effects of treatment of Gastrointestinal Carcinoid
tumors?
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For localized
gastrointestinal carcinoids, one of the following options may
be entertained:
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Appendicectomy, if the
lesion is located in the appendix with or without hemicolectomy
and/or radical hemicolectomy. |
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If the cancer is localised
to the rectum, diathermy to endoscopically
or colonoscopically resect the tumour, if it is very small Surgery
may be performed to remove the rectum, the anus, or the rectum
and anus together. This procedure is known as an abdominoperineal
resection in which two incisions are made, one over the abdominal
wall through which the specimen is mobilised in the path and one
in the perineum, which is the area between
the scrotum and the anus in males and the vulva and the anus in
females, through which the specimen is delivered out of the body.
The continuity of the gastrointestinal tract in order to deliver
the waste outside the body is maintained by making a fresh opening
or stoma
on the anterior abdominal wall. This opening is called a colostomy
and it is permanent in nature. To this is fixed a disposable bag
with a flatus filter. This bag is known as a colostomy
bag and will serve as a reservoir, which can be removed and
thrown daily with any stools, which collect into it. |
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If the tumour is localised to the small intestine, then a segmental
bowel resection is performed in which the offending area of
the bowel along with healthy margins of the small intestine are
resected and the portions, which are left discontinuous are joined
again (anastomosis). Along with this procedure,
lymph nodes have to be taken out just as in hemicolectomy. |
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If the cancer is localised
to the pancreas, or large
intestine, the treatment would be to remove the offending
organ or a healthy portion of it along with the tumour and with
the draining lymph nodes.
Some adjacent organs, which can be sacrificed, may also be done
so in the process. |
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gastrointestinal carcinoids, one of the following treatment
options may be entertained: |
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Surgery to remove the
organ affected. |
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If any other nearby organs
appear to be involved and can be sacrificed, then that also may
be performed. |
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metastatic gastrointestinal carcinoids, one of the following
treatment options may be entertained: |
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Palliative surgery to
bypass or relieve the symptoms caused
by the tumour. |
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Cryosurgery may be used
to freeze and kill the cancer or to just make the lumen of the
intestine patent again. This is by no means a definitive curative
surgery but it is just a surgery to cause relief of the morbidity
or symptoms caused by the tumour. |
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Chemotherapy to reduce
or palliate symptoms caused by the cancer. This is not only directed
towards the local effects which are caused by the cancer, but
also towards the hormonal effects that the cancer products may
be causing. |
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Hepatic artery ligation
or hepatic artery instillation of chemotherapy to kill cancer
cells, which have metastasised to the liver. |
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Radiation to relieve symptoms
caused by the gastrointestinal carcinoid tumor. |
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Injecting directly of
radioactive substances into the tumour to relieve the symptoms.
These radioactive substances are also known as radioisotopes
and have specific affinity for these particular carcinoid areas
or are labelled with particular cells, which have affinity for
these carcinoid cells. Thus, the radioactive source gets attached
to these carcinoid cells and cause reduction in the symptoms caused
by them. |
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Finally, biological or
immunological therapy may be attempted.
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What are the side effects of treatment for Carcinoid?
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Unfortunately
treatment for cancer does cause damage to the healthy tissues.
Please ask the clinician about any possible side effects before
any form of treatment commences.
The effects of radiation
depend upon the dose of radiation, the size of the area radiated,
and the number and size of each fraction.
The commonest side effect is extreme fatigue.
Although bed rest is good, most radiotherapists advise the patient
to be as mobile as possible.
Another common problem is that of radiation dermatitis
in which the skin covering the radiated area becomes red, dry,
itchy, and may show signs of scaling off. This will slowly settle
down after radiation ceases, but there may be a permanent 'bronzing'
of the skin. It is important to note here that this skin problem
is associated only with teletherapy or external radiation therapy.
Radiation also may cause nausea and vomiting,
diarrhea, urinary discomfort.
There may also be a fall in
the white blood cells, which are needed by humans to fight
infection.
Usually the radiotherapist can suggest the drugs and diet necessary
to alleviate such problems.
The various drugs in chemotherapy
cause a varied spectrum of side effects. The severity and variability
of these symptoms are very individualistic, changing from patient
to patient.
Some of the common side effects are:
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Skin Rashes. |
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Loss of hair. |
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Diarrhea. |
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Vomiting. |
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Tingling and numbness
in the fingers and toes. |
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Hearing loss. |
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temporary and recede after therapy is over. Hair growth gradually
starts after cessation of chemotherapy. |
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oncologist will usually be able to reduce the severity and spectrum
of these side effects. |
The psychology
of the patient is very important during therapy. Better psychologically
prepared the patient is, better are his chances of having decreased
side effects. The patient should drink large quantities of water
while the therapy is in progress, and preferably avoid uncooked
or raw food. Water should be filtered or boiled. Any relative
or person who has any sort of infection such as common cold should
be asked to desist from coming close to the patient.
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