Intraocular Melanoma
The Cancer of the Uvea
Overview
Intraocular melanoma is a rare type of cancer which forms in the melanocytes—the cells that produce melanin, which gives skin part of its pigment—of the eye. It begins in the uvea, which consists of three parts. The iris is the colored area at the front of the eye. The ciliary body is a ring of muscle that changes the shape of various structures in the eye. The choroid is the layer of blood vessels that supplies the eye with oxygen and nutrients. Most intraocular melanoma begins in the choroid, however it is possible for it to develop in the other two parts.
Signs, Symptoms, and Detection
There may be no early signs of intraocular melanoma, and it may not be detected until you have an eye exam. Symptoms include:
- Blurred or altered vision
- "Floaters" or flashes of light in your visual field
- A dark spot on the iris
- A change in the size or shape of the iris
- A change in the position of the eye in its socket
Treatment Options
Surgery
Removal of either the tumor alone or the entire eye, depending on the size of the tumor and how vision has been affected.
Watchful Waiting
Closely monitoring the patient's condition without providing any treatment. Usually used when no signs/symptoms are present, the tumor is not growing, or when the tumor is in the patient's only usable eye.
Radiation Therapy
The use of high-energy X-rays or other types of radiation to kill cancer cells or keep them from growing. This can be accomplished either externally or internally. Shown is the internal method, called Plaque Radiation.
Photocoagulation
The use of laser light to destroy blood vessels leading to the tumor to cut off the flow of nutrients to the cancer cells. This is used to treat small tumors.
Thermotherapy
The use of heat from the laser to kill cancer cells and shrink the tumor.
Prognosis
Higher chance of metastasis is associated with several factors:
- Large tumor size
- Ciliary body involvement
- Orange pigment over the tumor
- Age at time of diagnosis
About 50% of people develop a metastatic disease from intraocular melanoma writhin 15 years, and once it reaches the liver, the most likely site of metastasis, it is nearly incurable. However, if caught early, the above treatments can drastically extend life expectancy and improve quality of life for patients.
Risk Factors
Patients have a higher risk of developing intraocular melanoma based on several factors, mostly environmental in nature. These include:
- Exposure to natural or artificial sunlight (UV rays) over long periods of time
- Having light colored eyes (blue or green)
- Older age
- Caucasian descent
- Family history of skin problems or diseases
- Abnormal pigmentation of the uvea
- Mutations in the GNAQ, GNA11, BAP1
As with all forms of melanoma, one of the most important ways to reduce your risk of developing intraocular melanoma is to reduce UV exposure. Also, eating right, exercising regularly, and relieving stress can help prevent the development of the disease. It is also recommended to get regular ophthalmology exams.
Research and Future Treatments
Researchers are currently studying genes associated with intraocular melanoma to discover who is at a greater risk and determining the prognosis of those who have it. Future treatments include immunotherapy, which boosts the body's ability to attack cancer, and targeted therapy, which uses drugs to directly attack genetically-mutated cells.