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Goals of Treatment ~
The goal of treatment of a patient with uveal melanoma is to save the patient’s life. If possible, salvage of the eye and vision is achieved.
In the past, surgical removal (enucleation) was the only method to treat uveal melanoma. Over the past three decades, improved conservative treatment methods have been developed to save the eye as well as the patient’s life. The choice of treatment method depends on several factors including the age and health of the patient and the size, location, thickness and growth pattern of the tumor. The management methods include observation, laser photocoagulation, transpupillary thermotherapy, plaqueradiotherapy, local resection, enucleation, exenteration and combination of these methods.
Observation ~
Some small, inactive melanomas are observed, especially if they occur in an elderly patient. Monitoring of the tumor every few months with examination, photography, ultrasonography and other tests is advised and if growth is detected, then interventional treatment is provided.
Laser Photocoagulation ~
Laser photocoagulation is used occasionally for small melanoma of the eye. Often, several sessions of laser are necessary over a few months. Currently, laser is most commonly used to treat radiation related side effects in the retina rather than treatment directly to the tumor.
Transpupillary Thermotherapy ~
This method provides focal heat to a tumor via a infrared beam directed through the pupil into the tumor. It is often coupled with radiotherapy.
Radioactive iodine plaque
Radioactive plaque on eye in operating room
Plaque Radiotherapy ~
Plaque radiotherapy is currently the most common form of treatment for uveal melanoma. It is used for small, medium, or large melanoma, but the side effects of treatment increase with increasing tumor size. This technique involves a small radiation plaque that is the size of a nickel and is surgically applied to the eye directly over the tumor. The plaque has carefully placed radioactive seeds on the side that faces the sclera. The seeds are carefully arranged on the plaque by specially trained radiation oncologists and physicists. After it is prepared, the plaque is sterilized and placed on the eye surgically by the ocular oncologist. It is left in place for 4 to 7 days to provide 8,000 centigray of radiation to the entire tumor. The remainder of the body receives only a tiny amount of radiation, about the equivalent of 1 chest xray. The radiation plaque is then removed in the operating room and the patient is discharged to home the day of plaque removal.
After plaque removal, the patient and his/her belongings are not radioactive. The goal of this treatment is to destroy the tumor and prevent it from spreading to other parts of the body. The radiation causes gradual shrinkage of the tumor to a smaller, visible scar. The brain, opposite eye, and other parts of the body show no effect from the plaque.
The effects of radiation on the tumor are seen in 3 to 6 months after treatment. In a less than 5% of patients, the tumor does not respond appropriately and a second plaque is necessary or the eye might need to be removed (enucleation). Radiation can affect the normal structures of the involved eye and cause cataract, glaucoma, and vision loss from hemorrhage, retinal edema, or optic nerve dysfunction. After radioactive plaque treatment, double vision for a few weeks to months might occur due to eye muscle imbalance. Fortunately, this usually clears on its own, and patients rarely need to have special prism eyeglasses or the muscles surgically balanced.
Choroidal melanoma before plaque radiotherapy
Choroidal melanoma after plaque radiotherapy
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Local Resection ~
Resection of uveal melanoma is a method of surgically removing the entire tumor from the eye and leaving the remainder of the eye intact. This is most often used for iris or ciliary body melanoma.
The surgery is performed in the operating room and typically requires 2 to 4 hours of tedious microscopic dissection. Only a few places in the world are capable of this difficult surgery because it requires a high level of skill. Following surgery, the doctor will monitor for wound leak, cataract, blood in the eye, retinal detachment and other side effects. Some patients need additional radiation. Fortunately, most eyes tolerate this surgery well.
Enucleation ~
Prior to the 1960’s the usual treatment for choroidal melanoma was enucleation (removal of the entire eyeball). Enucleation is still used to treat some large melanomas and even some medium or small melanomas where other treatments will not work.
Cross section of eye with melanoma.
Enucleation is performed in the operating room. The eye is removed and a ball implant (about the size of the eye) is placed in the remaining empty orbit. The eyelids and eye muscles remain. The patient is discharged from the hospital wearing a heavy patch. In 6 weeks, the patient visits an ocularist (an artist who designs artificial eyes) and a prosthesis (artificial plastic eye) is designed to match the remaining eye. The artificial eye is quite natural in appearance and in some cases shows a remarkable match to the opposite eye. Even though the artificial eye can move, the movement is not as full as the real eye. There is no surgery at present to transplant an entire eye.
After enucleation, there is a reduced visual field to the side of the artificial eye and there is some loss of depth perception as well. Many of the skills of depth perception are relearned with time and most patients continue with their same jobs and activities without difficulty.
Protective lens made of polycarbonate are advised to be worn at all times in the form of glasses during the day or goggles during activities or sports. Recommended reading for vision in one eye is a book entitled “A Singular View. The Art of Seeing with One Eye“ by Frank Brady, available online at www.amazon.com.
Exenteration ~
Exenteration is reserved for patients whose tumor has grown through the wall of the eye into the orbit. This surgery involves removing the eye as well as the surrounding eyelids and orbit. Fortunately, it is rarely necessary.
Combination Methods ~
Management of uveal melanoma typically involves a combination of methods such as plaque radiotherapy followed by transpupillary thermotherapy or local resection followed by plaque radiotherapy. Combination of methods can improve tumor control.
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