Radiation therapy uses high-energy radiation to kill cancer cells. It is being used more as doctors move away from surgery. Radiation therapy can often preserve some vision, although sometimes this is lost anyway because radiation damages other parts of the eye. Its main advantage is that the eye structure is preserved. This results in a better appearance for the patient. The results of radiation appear to be just as good as surgery for medium-sized tumors.

Brachytherapy: This form of radiation therapy places small pellets or seeds of radioactive material directly into or very close to the cancer. This has become the most commonly used radiation treatment for most eye melanomas. Brachytherapy for eye melanomas is also known as episcleral plaque therapy. A radioactive material (usually radioactive iodine, ruthenium, or palladium) is placed directly against that part of the eyeball just outside where the tumor lies. Tiny pellets of radioactive material are attached to metal plaque carriers that are shaped to fit next to the affected area, and to shield nearby tissues from radiation. An operation is needed to place the plaque under the conjunctiva next to the tumor. This surgery usually takes 1 or 2 hours. The plaque is kept there for a varying amount of time, usually 4 to 5 days, and you will probably remain in the hospital during this time. The length of time is determined by the size of the tumor and the strength of the radiation source. Surgery to remove the plaque usually takes less than an hour, and you will probably be able to go home the same day. This therapy usually cures 90% of small tumors and can preserve vision in some patients, depending on what part of the eye the melanoma is in. The outlook for vision after brachytherapy is less favorable if the tumor is located very close to the optic nerve, which carries signals from the eye to the brain.

External beam radiation therapy: This therapy uses radiation delivered from outside the body that is focused on the cancer. This is the type of radiation therapy originally used to treat eye melanomas. Today its use is generally limited to newer methods for accurately aiming external radiation, such as gamma knife treatment and intensity-modulated conformal therapy. Both of these methods concentrate highly focused beams of radioactivity on the tumor. These techniques have not yet been widely used.

Proton beam therapy: This is a form of external beam radiation therapy that uses a different kind of radiation that can be aimed very precisely. Devices that deliver proton beam radiation are available only in a few hospitals, although the number is increasing. The results of treatment seem similar to those for brachytherapy.

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