Cancer of the eye, or ocular cancer, can affect different parts of the eye, including the retina, iris and optic nerve. Uveal melanoma is the leading primary eye cancer in adults. It often strikes without symptoms and carries a risk of spreading to the liver, lung and skin. Diagnosis of uveal melanoma is best made with an examination known as indirect ophthalmoscopy, though other types of examinations can be used.
What are the symptoms?
Symptoms vary with the different types of eye tumors. Some of the more common types of eye tumors and accompanying symptoms are:
Tumors and inflammations can occur behind the eye. They often push the eye forward causing a bulging of the eye called proptosis. The most common causes of proptosis are thyroid eye disease and lymphoid tumors.
What are the treatment options?
Treatment of ocular melanoma is based on the part of the eye affected and whether it has metastasized, or spread, to other parts of the body. It is commonly treated with surgery and radiation therapy. Patients also can be treated with plaque therapy in which a small radioactive metal rod is placed near the tumor. Stereotactic radiosurgery is another treatment option.
Ocular melanoma surgery typically involves removing part of the eye or the entire eye in a procedure known as enucleation. This may be necessary with large tumors or when other treatment methods are not suitable. In cases involving complete removal of the eye, patients can be fitted with a prosthetic eye. Surgery remains the standard in treating ocular tumors.
Radiation therapy can be used by itself or after surgery. There are two types of radiation therapy: external and internal. Both use specific types of radiation to kill cancer cells.
Internal radiation, known as plaque therapy, uses a small radioactive “seed” implanted near the tumor site. The seed typically remains implanted for about seven days and is removed.
External-beam radiation therapy uses a highly accurate energy beam that limits damage to surrounding tissue and is typically used to treat tumors in the orbit of the eye (eye socket).
Radiation therapy has been shown to be effective when treating ocular melanoma, but it can cause side effects. Red and dry eyes are common among radiation therapy patients. Cataracts sometimes result from radiation therapy, but surgery may be an option to remove them. Eyelash loss and shortening may occur. Optic nerve damage, glaucoma and abnormal blood vessels in the retina can occur, though these side effects are less common.
Several radiosurgery systems are capable of high-dose radiation treatment with a variety of radiation sources. Nearly all methods use a metal frame attached to the patient’s skull with screws that immobilize the head to accurately target the tumor. Local anesthetic is used for mounting the frames, though frames can be uncomfortable and painful to some extent.
CyberKnife is the only radiosurgery system that doesn’t need an invasive head frame. Radiosurgery with CyberKnife delivers high-dose radiation while minimizing exposure to healthy tissue.
In certain cases, CyberKnife treatment may be preferred over standard radiation therapy because of its ability to spare healthy tissue surrounding the tumor. Ocular and orbital tumors can be difficult to treat due to their close proximity to critical structures in the brain, and CyberKnife provides an effective treatment option for these tumors due to the precise nature of the radiation beams it delivers. Ocular and orbital tumors can greatly affect a patient’s quality of life, and radiosurgery with CyberKnife offers a treatment option that can preserve a patient’s vision.