About Choroidal Melanoma
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.
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.
Eye movements after removal of the right eye
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.
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.
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.
Copyright © 1997, 1999, 2000, The Collaborative Ocular Melanoma Study.