Overview There are two primary types of eye cancer:
• Intraocular Melanoma • Retinoblastoma
This page discusses intraocular melanoma. See also Retinoblastoma.
Intraocular melanoma is a disease in which malignant (cancer) cells form in the tissues of the eye. Intraocular melanoma begins in the middle of 3 layers of the wall of the eye. The outer layer includes the white sclera (the "white of the eye") and the clear cornea at the front of the eye. The inner layer has a lining of nerve tissue, called the retina, which senses light and sends images along the optic nerve to the brain.
The middle layer, where intraocular melanoma forms, is called the uvea or uveal tract, and has 3 main parts:
• Iris The iris is the colored area at the front of the eye (the "eye color"). It can be seen through the clear cornea. The pupil is in the center of the iris and it changes size to let more or less light into the eye.
• Ciliary body The ciliary body is a ring of tissue with muscle fibers that change the size of the pupil and the shape of the lens. It is found behind the iris. Changes in the shape of the lens help the eye focus. The ciliary body also makes the clear fluid that fills the space between the cornea and the iris.
• Choroid The choroid is the layer of blood vessels that bring oxygen and nutrients to the eye. Most intraocular melanomas begin in the choroid.
Intraocular melanoma is a rare cancer, but it is the most common eye cancer in adults.
Symptoms Intraocular melanoma may not cause any early symptoms. It is sometimes found during a routine eye exam when the doctor dilates the pupil and looks into the eye. The following symptoms may be caused by intraocular melanoma or by other conditions. Consult a doctor if any of these problems occur:
• A dark spot on the iris. • Blurred vision. • A change in the shape of the pupil. • A change in vision.
Glaucoma may develop if the tumor causes the retina to separate from the eye. If this happens, there may be no symptoms, or symptoms may include the following:
Treatment Different types of treatments are available for patients with intraocular melanoma. Some treatments are standard (the currently used treatment, often referred to as “standard of care”), and some are being tested in clinical trials. A treatment clinical trial is a research study meant to improve current treatments or obtain information on new treatments for patients with cancer. When clinical trials show that a new treatment is better than the standard treatment, the new treatment may become the standard treatment. Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.
Five types of standard treatment are used:
Surgery Surgery is the most common treatment for intraocular melanoma. The following types of surgery may be used:
• Local tumor resection: Surgery to remove the tumor and a small amount of healthy tissue around it. • Enucleation: Surgery to remove the eye and part of the optic nerve. This is done if the tumor is large and vision cannot be saved. The patient may be fitted for an artificial eye after enucleation. • Exenteration: Surgery to remove the eye and eyelid, and muscles, nerves, and fat in the eye socket. The patient may be fitted for an artificial eye or facial prosthesis after exenteration.
Watchful Waiting Watchful waiting is closely monitoring a patient’s condition without giving any treatment until symptoms appear or change. A series of pictures is taken over time to keep track of changes in the size of the tumor and how fast it is growing.
Radiation therapy Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. There are two types of radiation therapy. External radiation therapy uses a machine outside the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer. The way the radiation therapy is given depends on the type and stage of the cancer being treated.
Localized plaque radiation therapy is a type of internal radiation therapy that may be used for tumors of the eye. Radioactive seeds are attached to a disk, called a plaque, and placed directly on the wall of the eye where the tumor is located. The side with the seeds faces the eyeball and delivers radiation to the eye. The plaque, which is often made of gold, helps protect nearby tissues from radiation damage.
Charged-particle radiation therapy is a type of external radiation therapy. A special radiation therapy machine aims tiny, invisible particles, called protons or helium ions, at the cancer cells to kill them with little damage to nearby normal tissues. Charged-particle radiation therapy uses a different type of radiation than the x-ray type of radiation therapy.
Gamma Knife radiosurgery may be used for some melanomas. This non-surgical treatment aims tightly focused gamma rays directly at the tumor so there is little damage to healthy tissue. Gamma Knife is a type of stereotactic radiosurgery.
Photocoagulation Photocoagulation is a procedure that uses laser light to destroy blood vessels that supply nutrients to the tumor, causing the tumor cells to die. Photocoagulation may be used to treat small tumors. This is also called light coagulation.
Thermotherapy Thermotherapy is the use of heat to destroy cancer cells. Thermotherapy may be given using:
• A laser beam aimed through the dilated pupil or onto the outside of the eyeball. • Ultrasound. • Microwaves. • Infrared radiation (light that cannot be seen but can be felt as heat).
