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Other Background (courtesy COMS)
 Choroidal
melanoma is diagnosed during an examination of the eye by an
ophthalmologist. Your eye doctors are able to recognize a choroidal
melanoma by the degree of pigmentation of the tumor, by its shape
and location, and by other features observed in an eye examination.
Unlike tumors in other parts of the body, choroidal melanoma is
directly visible through the "window" provided by the pupil. Most of
the time, the ophthalmologist can be nearly certain of the diagnosis
from clinical appearance, photographs, and ultrasound pictures.
Therefore, biopsy, which is often indicated to diagnose tumors in
other parts of the body, is avoided.
Some specialized tests which use sound waves (echography or
ultrasound) and fluorescent dye (fluorescein angiography) may help
your doctor to make the diagnosis of choroidal melanoma more
certain. In the
echography test, soundwaves are directed towards the tumor by a
small probe placed on the eye.
The pattern made by reflection of the sound waves helps your doctor
to diagnose the tumor.
 
A test called
fluorescein angiography also may be useful. In this test, a
fluorescent dye is injected into a vein in the arm. As the dye
passes through the blood vessels in the back of the eye, a rapid
sequence of photographs is taken through your pupil. The appearance
of the eye on these photographs may help your doctor to diagnose
choroidal melanoma. Using the information provided by these tests,
your doctor has been able to determine that your tumor is a "medium"-sized choroidal melanoma. Although it is classified as
"medium," the melanoma is only about the size of a pea.
Some choroidal melanomas appear to
remain dormant and do not grow. Most enlarge slowly over time and
lead to loss of vision. These tumors can spread to other parts of
the body and lead eventually to death.
Treatment of choroidal melanoma is
recommended when your doctors judge that, on the basis of your
medical history and the findings from the eye examination, your
tumor is likely to enlarge and possibly spread to other parts of
your body if left untreated.
For 100 years or longer, the usual
treatment for choroidal melanoma has been removal of the eye, or
enucleation. If the tumor has not spread to other parts of the body,
then removal of the eye rids the patient of the tumor.
Since World War II, radiation
treatment has been used for choroidal melanoma. During the past 20
years, this method of treatment has been refined. Radiation, at the
appropriate dose rates and in the proper physical forms, is intended
to eliminate growing tumor cells without causing damage to normal
tissue sufficient to require removal of the eye. As the cells die,
the tumor shrinks, but it usually does not disappear entirely. The
most promising widely available method for irradiating medium
choroidal melanoma involves constructing a small plaque with
radioactive pellets glued to one side. Doctors who take care of
patients who have choroidal melanoma are enthusiastic about the
possibilities for this treatment, but satisfactory information about
long-term results is not available. Your doctors recognize that they
have a responsibility to current and future patients with choroidal
melanoma to test radiation in a clinical trial.
High energy particles (helium ion
or proton beam radiation) from a cyclotron also can be used to
irradiate tumors. Surgery is performed first to sew small metal
clips to the sclera so that the particle beam can be aimed
accurately. Treatment is given over several successive days. The
equipment needed for these treatments is available only in a few
centers in the world. Good results have been reported in some
patients, but many patients treated in this way have been followed
for only a few years. Therefore, the long-term results of these
forms of radiation therapy compared with the more commonly used
plaque are unknown.
Over the years, other treatments
have been used for a small number of patients. Photocoagulation
using white light or laser light has been used to burn small tumors,
and cryo-therapy has been used to kill the tumors by freezing them.
These techniques are believed to work only for very small tumors.
Some doctors have combined laser or cryotherapy with radiation, but
such treatments are experimental. A few patients have had eye wall
resection or a related procedure to remove tumors from their eyes.
These methods of treatment are considered experimental by most
doctors and have been used only for a small number of tumors. No
treatment is available that can guarantee to destroy the tumor, to
preserve vision, or to assure a normal lifespan.
For enucleation surgery, the
patient is admitted to the hospital and the eye is removed under
either local or general anesthesia. The enucleated eye cannot be
treated or repaired and replaced in the eye socket. Instead, it is
replaced with a ball implant that may be made of plastic or other
materials. The implant is sewn into position and the eye is allowed
to heal. The patient usually leaves the hospital one or two days
after surgery. In some cases, patients are permitted to go home the
same day. Three to six weeks later, a specialist who makes
artificial eyes (called an ocularist) fits the patient with a
prosthesis. The prosthesis is a plastic shell painted to resemble
the other eye and inserted between the eyelids. When the other eye
moves, the ball implant moves also, causing the prosthesis to move
with the normal eye. Movement is usually less than that of the
normal eye; however, the doctor and close relatives are most often
the only people to notice that the patient does not have two normal
eyes. If you have questions about different types of implants, be
sure to ask your doctor. The purpose of the implant is to replace
the volume in the socket that had been taken up by the eye.
What are the consequences of
enucleation?
Enucleation surgery removes the
tumor from the body if no spread outside the eye has occurred.
Unfortunately, loss of vision for the eye removed is permanent
because an entire eye cannot be transplanted. There is a reduced
visual field on that side of the body when looking straight ahead,
and there is loss of depth perception (stereopsis) as well. You can
imagine what enucleation would be like by closing or patching one
eye. Many of the skills of depth perception may be relearned with
time; thousands of people have lost one eye and continued to live
normal, productive lives. The book A Singular View, The Art of
Seeing With One Eye, by Frank B. Brady is an excellent
reference.
Although the cosmetic results
after removal of the eye and fitting of an artificial eye are
usually good, the eye often does not move as well as the natural
eye. There also may be some differences in the position of the
eyelids when compared to the natural eye and the position of the
artificial eye may look slightly abnormal. Despite these potential
problems, the cosmetic appearance after enucleation is usually quite
good.
After enucleation there may be
some temporary pain which can be relieved by medication. Possible
surgical complications include hemorrhage, complications of
anesthesia, and late infection requiring removal of the implant.
These serious problems are rare. Several years ago a suggestion was
made that enucleation surgery might promote spread of tumor cells
into the bloodstream during the operation and thereby lead to a
reduced lifespan for the patient. This theory has never been proven
and is not generally accepted. It is important to know that
enucleation surgery for melanoma, like all cancer surgery, is
performed in a way to minimize the possibility of spreading the
cancer during the operation. Radioactive plaque therapy and eye wall
resection also involve significant surgical manipulation of the eye.
Thus, the risk of spreading the tumor by surgical manipulation is
probably the same with enucleation as with other forms of therapy
requiring surgery.
 When
using radiation to treat medium choroidal melanoma, the goal is to
destroy the tumor and save the eye. If the eye is to be saved, it is
important to give high doses of radiation to the tumor and very
little to the rest of the eye. This goal often can be accomplished
with a small radioactive plaque sewn or sutured to the outside of
the eye over the base of the tumor. This type of radiation procedure
is sometimes called brachytherapy. The plaque is constructed with
radioactive iodine seeds or pellets (A) glued to one side (B) and a
thin gold sheet (C) attached to the other. Since gold stops this
particular type of radiation, it acts as a shield to protect the
parts of the head around the eye from radiation damage, especially
those tissues beyond the shield.
 For
placement of a radioactive plaque, the patient usually is admitted
to the hospital. Surgery under local or general anesthesia is
required and usually takes one to two hours. An incision is made in
the conjunctiva, a thin membrane which covers the outside of the
eye, and the radioactive plaque is stitched to the outside of the
eye over the tumor. The conjunctiva is then sewn back over the
plaque. In many medical centers, the patient stays in the hospital
until the plaque is removed. After approximately three to seven
days, surgery is performed again to remove the plaque. (Careful
calculations determine how long the plaque must remain in place to
give the tumor the proper amount of radiation.) Surgery for removal
of the plaque takes less than an hour, under either local or general
anesthesia, and often the patient can go home later the same day.
What are the consequences of
radiation treatment?
When radioactive plaque therapy is
successful, the tumor stops growing and may shrink over the course
of 6 to 12 months. The patient keeps his or her own eye and, in
favorable circumstances, when the tumor responds well and is located
away from the most important parts of the eye, the tumor is
destroyed and the patient may be able to see with the eye.
Radiation from a radioactive
plaque does not always destroy or inactivate the tumor. The tumor
may grow and the eye may have to be removed at a later time.
Delaying removal of the eye may allow the tumor to spread elsewhere
in the body.
Radioactive plaque therapy
requires two operations. Risks during surgery are similar to those
described earlier for enucleation surgery. Compared to enucleation,
there are added costs for a second operation, for the radioactive
plaque, and for a longer hospital stay. Radiation almost always
damages some healthy parts of the eye. Radiation damage to the blood
vessels of the retina (radiation retinopathy) or to the optic nerve
often causes a gradual loss of vision. In some cases, hemorrhage
(bleeding) into the inner part of the eye (vitreous cavity) may
occur and cause loss of vision. Radiation damage to the lens may
cause a cataract, which may require removal by surgery sometime
later.
After radioactive plaque
treatment, many patients note some dryness and irritation of the eye
which usually can be relieved by use of eye drops called artificial
tears. In some instances, eyelashes may be permanently lost. In rare
instances the outside layer of the eye (sclera) may become very
thin. Occasionally, there may be prolonged redness, irritation, or
infection inside the eye. The patient may see double if the muscles
are damaged during the operation to apply or remove the plaque.
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