What Is It?
Choroidal melanoma is a cancer of the eye that develops from the pigmented cells of the choroid, the spongelike membrane that lies between the sclera (the white of the eye) and the retina. The choroid is rich in blood vessels, and supplies nutrients to the retina. Choroidal melanoma is a primary cancer, meaning the tumor originates in the eye rather than moving to the eye from cancer in another part of the body. Although choroidal melanoma is a rare form of cancer, it is the most common primary eye cancer in adults.
Over time, many choroidal melanomas enlarge and cause the retina to detach, which can lead to vision loss. The tumors also can spread (metastasize) to other parts of the body and cause death. Choroidal melanomas most commonly spread to the liver. According to the U.S. National Institutes of Health, 1,680 to 2,240 new cases of this cancer are diagnosed each year in the United States and Canada, which is about six to eight new cases per million people each year. People who are middle-aged or older are most susceptible.
This cancer often causes no symptoms in its early stages, so the tumor may grow for some time before the problem becomes noticeable. When symptoms occur, they include blurred vision, floaters, flashing lights or severe eye pain. These symptoms also can be caused by many other, more common noncancerous causes.
Most cases of choroidal melanoma are detected during a routine, dilated-eye exam, in which an ophthalmologist dilates the pupils to examine the back of the eye Most of the time, a choroidal melanoma can be diagnosed through a clinical examination alone. During a dilated-eye exam, the ophthalmologist is able to recognize choroidal melanoma by the tumor’s pigmentation, its location and shape, and other clinical observations. Specialized tests can help make the diagnosis more certain:
- Echography — A small probe is placed on the eye, directing sound waves toward the tumor and recording the pattern as the waves reflect off the tumor.
- Fluorescein angiography — A fluorescent dye is injected into a vein in the arm, and a rapid sequence of photographs is taken through the pupil as the dye passes through the veins in the back of the eye.
Once it develops, choroidal melanoma often will continue to grow unless it is treated. Treatment is recommended if findings indicate that the tumor is likely to enlarge and cause loss of vision, or possibly spread to other organs.
The causes of and risk factors for choroidal melanoma are not well understood. No particular ways for preventing this specific cancer are known, but general guidelines include a diet that includes fruits and vegetables.
Management and treatment of choroidal melanoma will depend upon the size of the tumor. If the choroidal melanoma is small (less than 2.5 millimeters high), often nothing is done and the tumor is monitored. Treatment is started if the melanoma grows.
Medium and large choroidal melanomas usually are treated with radiation or surgery. Radiation therapy may be administered by several methods. Local radiotherapy is delivered via a small, metal, dish-shaped device that contains radioactive iodine. The device is stitched to the sclera so that the radiation can target the tumor precisely. In some cases, surgery to remove the eye (enucleation) is necessary. Most ophthalmologists recommend removal of the eye for large choroidal melanomas. After the eye is removed, a prosthetic eye is placed into the socket. Cosmetically, the fake eye can look good, but it often does not move as well as a natural eye.
Everyone treated for choroidal melanoma need to be monitored for the rest of his or her life to detect early signs of the cancer spreading. If choroidal melanoma has already spread at the time of diagnosis, treatment is a subject of controversy, since there is little clinical evidence that radiation or surgery to remove the eye affects the outcome at all. There is no effective treatment for choroidal melanoma that has spread. Researchers are continuing to investigate whether chemotherapy and immunotherapy treatments after the eye is removed can reduce the risk of death from metastatic choroidal melanoma.
When To Call A Professional
Visit your doctor for a complete eye examination if you experience changes in your vision. You should call your doctor right away whenever you have blurred vision, floaters, flashing lights or severe pain in or around your eye or if you experience any loss of vision. You may need to be seen immediately in the office or in an emergency room.
The prognosis will depend upon the size of the tumor at the time of diagnosis. The prognosis is better with early detection and treatment will improve the prognosis.
Diseases and Conditions Center
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.