Ocular melanoma is a type of cancer that arises from the cells in the eye that make melanin. Ocular melanomas can form from the pigmented cells of the iris, but the majority of ocular melanomas form in the back of the eye and are called choroidal melanomas. Ocular melanomas, like other types of melanomas, can spread to other parts of the body; the eye doctor and a cancer doctor will evaluate this possibility. If the melanoma is small, the eye doctor may observe the tumor for a while to see if it gets larger or begin treatment, which may include resection surgery, radiotherapy, thermotherapy and removal of the eye completely (enucleation). If the cancer has spread, the patient may have to undergo additional therapies.
Resection Surgery
Depending on the size of the tumor, the eye surgeon may perform surgery to just remove the tumor and some tissue around it. If the tumor is located on the iris, the surgeon may excise the tumor and sew the edges together. The amount of tissue removed depends on the amount of spread of the tumor. For choroidal melanomas, the surgeon will remove the melanoma and choroid that is involved, but the surgeon may also remove the outer wall of that segment of the eye (sclera).
Radiotherapy (Brachytherapy)
In brachytherapy, also known as plaque therapy, a radioactive plaque is sewn to the eye over the melanoma during a surgical procedure. The plaque is usually left in place for up to five days and removed by the eye surgeon. This type of therapy is generally performed for choroidal melanomas (melanomas in the back of the eye) that are small or medium size. The radiation is limited to the eye because of the materials in the plaque and has been found to be safe. However, this therapy may cause some vision damage, and the amount of damage depends on the proximity of the tumor to the optic nerve.
Radiotherapy (External Beam)
Radiotherapy using radiation from a machine can also be used to treat ocular melanoma. The concept of this treatment is similar to radiation therapy for other types of tumors; the area of the tumor is marked so that the radiation beam can be aimed correctly and the treatments are given over several days. As with plaque therapy, radiotherapy can cause vision loss.
Thermotherapy
Thermotherapy uses heat to destroy the ocular melanoma cells and is usually only used for small tumors located in the back of the eye. This procedure uses a diode laser at lower power levels to slowly and gently heat the tumor itself, causing less damage to the retina and the tissues around it. This type of therapy is not commonly used because of the risk of recurrence of the cancer.
Enucleation
For very large tumors that cannot be treated by other methods or when the tumor has recurred after the use of radiation or thermotherapy, enucleation, or complete removal of the eye, is often the best therapy. This surgery is performed under general anesthesia. After the removal of the eye, a round implant is placed in the eye socket, and the eye muscles are attached so that the implant can move. Once the patient has healed, an artificial eye (prosthesis) is made. This is custom created to match the patient's other eye so that the appearance of the artificial eye will be as normal as possible.
