Ocular melanoma is a type of tumor that occurs in our eyes. This is a very rare form of melanoma that does not develop due to sun exposure.

Ocular melanoma is an extremely rare form of cancer that affects the eye with an incidence of 6 per million adults. Although rare, it is the most common primary cancer of the eye in adults. Primary means that the cancer began at that site (in this case the eye) and did not spread there from another part of the body. In most people, this cancer arises in a part of the eye known as the uveal tract.
The uveal tract is the colored (pigmented) layer of tissue that is found beneath the white of the eye (sclera) and is composed of normally pigmented cells and blood vessels. In the front of the eye, the uvea is made up of the colored part of the eye (iris) and a circle of muscle tissue (ciliary body) that releases a transparent fluid (aqueous humor) into the eye and helps to control the shape of the lens. The largest area of the uveal tract is in the back part of the eye (choroid) which is located beneath the retina, the vision sensing portion of the eye. In most instances, ocular melanomas arise within the choroid.

Ocular melanoma arises from cells called melanocytes, which are the cells of the body that produce pigment. Ocular melanoma is a cancerous (malignant) tumor that can potentially spread (metastasize) to other parts of the body, most often to the liver. The exact cause of this disorder is unknown, but several risk factors have been identified.

Although these choroidal melanocytes are similar to those cells found in the skin that produce skin pigment, when choroidal melanocytes transform into cancerous cells it is called choroidal (or uveal) melanoma. However, cutaneous (skin) melanoma and uveal (ocular) melanoma are distinct conditions which share the same name but are biologically and genetically very different diseases. It is extremely rare for skin melanoma to spread into the eye and nearly unheard of for ocular melanoma to spread to the skin.

Signs & Symptoms

Ocular melanoma may or may not cause symptoms. This generally depends on the exact location, size of the tumor within the eye, and if the tumor is causing secondary effects to the retina. An ocular melanoma may not cause any symptoms (clinically silent) for many years before symptoms begin. When symptoms develop they can include:

• blurred vision,
• double vision (diplopia),
• irritation,
• pain,
• a perception of flashes of light in the eye (photopsia),
• a reduction in the total field of vision, and loss of vision.

Additional symptoms that have been reported include

• a sensation of a foreign body like a speck of dust in the field of vision (floaters),
• redness,
• bulging or displacement of the eye (proptosis),
• a change in the shape of the pupil,
• pressure within the eye.

Some individuals may develop metamorphopsia, a distortion of vision where, when a person looks at a grid of straight lines, the lines appear wavy and parts of the grid appears blank.

When an ocular melanoma occurs in the choroid, this can lead to detachment of the retina, the nerve-rich membrane lining the back of the eyes. When an ocular melanoma occurs in the ciliary body, it can displace the lens of the eye causing blurry vision from cataract or a rapid change in eyeglass prescription (astigmatism).

An ocular melanoma has the potential to spread (metastasize) to other areas of the body. The liver is the most common organ in the body affected by metastasis of an ocular melanoma (80% of cases) but less often may involve the lungs, skin or soft tissue, and bone. Some estimates suggest that in 40-50% of individuals, an ocular melanoma will metastasize. Based on the aggressiveness of the particular tumor, as defined by clinical and genetic features, metastasis may be detected as early as 2-3 years after diagnosis and rarely as late as decades after treatment. Symptoms will depend upon what part of the body is affected and how long the metastasis has been present. Metastasis is a severe complication of the disease that has a high mortality rare due to lack of definitive treatments to eradicate all metastasis, though recent advances have shown success in certain instances.

There are some differences in metastatic risk based on where in the uveal tract the ocular melanoma develops. For example, iris melanomas have a very low rate of metastasis compared to ciliary body and choroidal melanomas. Advances in genetic testing of individual ocular melanoma tumors has helped to better customize a patient’s risk of developing metastasis independent of the tumor location or tumor size.

Standard Therapies

Treatment

The therapeutic management of individuals with ocular melanoma may require the coordinated efforts of a team of medical professionals, such as specialists in the diagnosis and treatment of eye disorders (ocular oncologists who are specially trained ophthalmologists), eye surgeons, physicians who specialize in the diagnosis and treatment of cancer (medical oncologists), physicians who use radiation to treat cancer (radiation oncologists), and other healthcare specialists. Psychosocial support for the entire family is essential as well.

Specific therapeutic procedures and interventions may vary, depending upon numerous factors, such as disease stage; tumor size; specific location of the tumor within the eye; the presence or absence of certain symptoms; an individual’s age and general health; and/or other elements. Decisions concerning the use of radiation therapy, experimental therapies, and/or other treatments should be made by physicians and other members of the health care team in careful consultation with the patient based upon the specifics of his or her case; a thorough discussion of the potential benefits and risks, including possible side effects and long-term effects; patient preference; and other appropriate factors.

Very small melanomas may not require treatment, and physicians may recommend watch and wait. Watch and wait refers to when physicians follow a patient with a slow-growing disorder without giving treatment until progression of the disease occurs. This allows some people to avoid undergoing therapies for many years. However, there is an increasing trend to treat even small melanomas earlier in many centers around the world.

The two main therapeutic options are radiation therapy or surgery. Procedures that use local radiation to destroy tissue and cancer cells (radiotherapy) such as brachytherapy are often used, especially for small- or medium-sized ocular melanomas. Radiation therapy produces damage to the tumor cells causing them to die and the tumor to slowly shrink in size. The most common method of treating the eye with radiation therapy is a process called brachytherapy, which may also be known as “plaque therapy,” endocurietherapy, or sealed source radiotherapy. During brachytherapy, radioactive material (implant) is placed on a small disk called a plaque. This disk is inserted into the eye socket next to or near the base of a tumor and secured to the outside of the eye. The disk is left in place for several days and then removed. Sometimes, external beam radiotherapy may be used with a specialized technique called proton beam radiation. This procedure uses a machine outside of the body that delivers laser beams to the eye to destroy cancer cells. There are different types of external beam radiotherapy. Both plaque brachytherapy and proton therapy are effective treatments for ocular melanoma.

Other procedures that have been used to treat ocular melanoma include the use of an intense, focused light (e.g. laser therapy) to heat and destroy tissue and cancer cells (laser photocoagulation) or the use of a different type of laser to heat and destroy tissue and cancer cells (transpupillary thermotherapy).

There are a variety of surgical techniques that are also used to treat ocular melanoma. Sometimes, physicians will recommend surgical removal (resection) of the entire affected eye (enucleation). Other times, physicians may recommendation surgical removal of the tissue that is affected by the disease (local resection). For example, an iris melanoma is often treated by surgical removal (resection) of the affected tissue.

Investigational Therapies

There is no approved therapy treatment for metastatic disease arising from a uveal melanoma. Various therapeutic options have been tried in individuals or small series of patients. These treatments include chemotherapy, drugs that target the immune system to treat cancer (immunotherapy), the use of cold to destroy cancerous tissue (cryotherapy), drugs that targets specific proteins thought play a role in tumor growth, and surgery. None of these therapies have yet to show significant or lasting improvement. More research is necessary to find better therapies for individuals with uveal melanomas.

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

You can also seek help and advice from the foundation, which will prompt you on treatment, as well as provide emotional support through the Artes Union app.

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