Melanoma is commonly considered a form of skin cancer. While it is certainly true that most cases of melanoma occur on the skin, this is a disease that can also occur in parts of the body other than the skin including the eye and on the mucosal surfaces of the body.
Ocular melanoma is a rare form of melanoma that can start from melanocytes within the eye, including the conjunctiva, the mucosal surface lining the eye and the eyelid, as well as the uveal tract of the eye. Melanoma starts in the conjunctiva is called conjunctival melanoma while melanoma starting in the uveal tract of the eye is called uveal melanoma. Although both develop in the eye, these two diseases are biologically and clinically different from one another, and both are very different from the more common form of melanoma occurring on the skin.
Conjunctival melanoma is a rare disease with no clear cause and usually appears as a pigmented spot on the eye. Individuals diagnosed with conjunctival melanoma commonly have a resection of the melanoma by an ophthalmologic oncologist and may receive further treatments to the eye such as cryotherapy, topical chemotherapy, or radiation treatment. Despite aggressive treatment primary conjunctival melanoma may recur. In a large part because of the rarity of conjunctival melanoma, there is no standard recommendation for the treatment of patients with advanced disease. Generally, these patients are treated similarly to patients with advanced melanoma, using immunotherapy, and targeted therapy, if applicable.
Uveal melanoma is also a rare disease, but, although rare, is the most common primary cancer of the eye in adults. Many individuals at first develop changes in their vision, but some cases are diagnosed during a routine eye exam without the patient having any symptoms. The most common treatments used for uveal melanoma include use of a radioactive plaque, proton beam therapy, or removal of the eye. As with conjunctival melanoma, ocular melanoma can recur even with aggressive treatment of the primary uveal melanoma. The risk of the melanoma returning can be estimated by the size of the melanoma as well as other clinical and pathological factors, by looking at changes in the chromosomes of the tumor (i.e., cytogenetic testing), and by looking at an altered pattern of genes that are expressed (i.e., gene expression profiling).
What is unique about uveal melanoma is its tendency to spread and grow in the liver in cases that do recur. Advanced uveal melanoma is a challenging disease to treat, and there is currently no significantly effective standard treatment for this disease. A broad range of treatments has been used, including chemotherapy, immunotherapy, molecularly targeted agents, and a number of liver directed treatments such as bland embolization, chemo embolization, immuno embolization, radio embolization, and infusion of chemotherapy into the liver, and others. Given the limited effectiveness of available treatments, significant effort has been made to develop new and more promising treatments for these patients and these are now being tested in clinical trials.
Despite the significant advances made in our understanding of conjunctival and uveal melanoma, these diseases are still challenging to treat. While the new immunotherapies and targeted therapies have significantly improved outcomes in patients with cutaneous melanoma, they generally have limited value in uveal melanoma, and it is not clear how effective they will be in conjunctival melanoma. To develop more successful treatments, we must support combined efforts between patients dealing with these diseases, the doctors caring for them, and the laboratory and clinical researchers working to develop new treatments for conjunctival and uveal melanoma. It is through this kind of cooperation that we can increase education and awareness of these rare diseases and ultimately identify new, more effective, and potentially curative treatments.
If you have ocular melanoma, you can also find assistance at A Cure In Sight.