The eye is the second most common site in the body for melanomas after skin. However, with only 2,500 cases a year, ocular melanomas are relatively rare and require special techniques for diagnosis and treatment.
Like melanoma of the skin, ocular melanoma often begins with the emergence of a cluster of melanocytes called a nevus (mole). More than 10 percent of the population will develop a nevus in the eye during their lifetime. Nearly one in 5,000 of these will become cancerous.
Types of Ocular Melanoma
Most ocular melanomas occur in the part of the eye known as the uveal tract, the vascular layer that includes the iris (the pigmented cells surrounding the pupil), ciliary body (the ring-shaped muscle that changes the size of the pupil and the shape of the lens when the eye focuses), and choroid (the pigmented layer under the retina). Choroidal melanoma is the most common type of ocular melanoma.
Melanoma also may occur in the eyelid, the conjunctiva (the filmy white covering of the eye), and the optic nerve. Most people with ocular melanoma experience no symptoms until the tumor has become large enough to interfere with vision. Untreated, however, ocular melanoma may spread through the bloodstream to other organs. Melanomas of the iris often respond better to treatment than those of the ciliary body.
Diagnosing Ocular Melanoma
Ocular melanoma may first be detected by an ophthalmologist during a routine eye examination in which the pupils are dilated. Diagnosis of ocular melanoma is usually made without a biopsy and is based on the appearance of the tumor, ultrasound results, or other test results. Digital photography of the inside of the eye aids in diagnosis. Many conditions other than melanoma of the eye are often confused with true melanomas.
Treating Ocular Melanoma
Treatment of ocular melanoma depends on which part of the eye is affected. Surgery may be used to remove part or all of the iris, ciliary body, or choroidal tumor. In some cases, surgery to remove the eye (enucleation) may be required.
Our ocular melanoma team is one of a few groups with significant experience in treating choroidal melanoma patients with brachytherapy, a type of radiation therapy in which radioactive material is placed directly on the tumor with a wire plaque. Research has shown that survival for patients with medium-sized choroidal tumors is nearly identical for those who received brachytherapy or enucleation.
Other tumors that occur in the conjunctiva, including squamous cell carcinoma and sebaceous carcinoma, are treated with combinations of microsurgery, topical chemotherapy, and cryotherapy (freezing). Laser therapy, also called transpupillary thermotherapy, is used occasionally to shrink smaller tumors. Doctors at Memorial Sloan-Kettering recently introduced the use of a photodynamic laser that destroys some conjunctival tumors without surgery.
Most tumors that occur in the orbit (eyeball), including the lacrimal (tear-producing) gland tumors, are benign and may require no treatment. For benign tumors that require surgery, Memorial Sloan-Kettering uses a multidisciplinary approach, utilizing the skills of ophthalmic oncologists, head and neck surgeons, and neurosurgeons.
Some orbital tumors, including certain lacrimal gland tumors, hemangiomas, neurolemmoma, rhabdomyosarcomas, and meningiomas, are malignant. At Memorial Sloan-Kettering, we combine surgery, radiation therapy, and chemotherapy to treat these cancers. Some patients with metastatic ocular melanoma may be eligible to participate in a clinical trial.
