Radiation Therapy for Intraocular Melanoma

Plaque brachytherapy is the most commonly used treatment to destroy intraocular melanomas and prevent them from growing and spreading. Eye cancer specialists at NYU Langone have one of the world’s highest success rates with this therapy.

This type of therapy is a localized treatment, meaning that a material containing radiation is placed directly on or near the tumor, sparing other tissues in the eye. Because surgery is required to place and remove plaque brachytherapy, treatment is given in an outpatient setting with general anesthesia.

First, your eye cancer specialist sews a small gold plaque, which contains rice-sized radioactive “seeds,” directly onto the wall of the eye, or sclera, underneath the tumor. The plaque is customized to cover the entire tumor, including a margin surrounding it.

For iris melanomas, our doctors also place a thin membrane made of donated amniotic tissue—the innermost layer of the sac that holds an unborn child in the womb—between the metal plaque and the cornea. The amniotic membrane protects the cornea and makes treatment more comfortable. The radioactive eye plaque is typically left in place for five to seven days before it is removed.

If the tumor touches or surrounds the optic nerve, our eye cancer specialists use a specially developed “slotted plaque” that allows it to fit around the optic nerve. This approach is the only one that includes the entire tumor in the radiation field.

Although highly effective in eliminating most intraocular tumors, plaque brachytherapy can lead to a progressive condition called radiation retinopathy, in which radiation damages blood vessels years after treatment. Radiation retinopathy can be treated with medications that block vascular endothelial growth factor, a protein that promotes the growth of abnormal blood vessels. Plaque brachytherapy may also cause a cataract, a cloudy patch in the lens of the eye that can interfere with vision.

If needed, our ophthalmic specialists can prescribe laser therapy to treat radiation retinopathy. They may recommend corrective eyeglasses or surgery to treat a cataract.

Rarely, our doctors may recommend another type of radiation therapy, known as proton beam radiation therapy, for people who have tumors that are too large to be treated with plaque brachytherapy. It’s also used for people who are too ill to have the surgery required to sew on and remove the plaques. This approach may also be recommended as an alternative to surgical removal of the eye, called enucleation.

In proton beam radiation therapy, a machine called a cyclotron directs radiation to a tumor from several different directions. Before this treatment, your eye cancer specialist performs surgery to attach metal clips to the eye around the base of the tumor. These clips help direct radiation to the tumor.

Doctors usually give the radiation dose in three fractions, or treatment sessions, during a one-week period. During these sessions, your eye remains completely still to ensure that the radiation does not harm normal tissues.

Because radiation enters the front of the eye before it reaches the tumor, proton beam radiation therapy can cause eyelash loss; irritation of the membranes that cover the eye, called the conjunctiva and cornea; and dry eye. This treatment can also stimulate the growth of new blood vessels in the iris, which can lead to radiation-associated glaucoma, an increase in eye pressure that can damage the optic nerve.

Our eye cancer specialists offer a variety of treatments to manage these side effects.