Uveal melanoma is a cancer that develops in the eye. Malignancy begins in the uvea and often spreads to other body organs such as liver and lungs. Statistics estimate that about 4% of all cases related to melanoma are accounted for by this type. It also is most common of all primary ocular melanomas. In recent days, advanced treatments and accurate diagnosis techniques have been developed. About half of all uveal melanomas still metastasize however.
Small t tumors are easy to remove even without risk of vision loss or complete eye removal. Complications arise when tumors have grown very big, are painful or have spread. In that case, more than one treatment option is often necessary.
What is uveal melanoma?
Melanomas are often described according to the organ or part of the body they invade. The uvea is made up of three main parts;
About 80% of all blood vessels that nourish the eye are contained in the choroid. Many eye melanomas grow in this region. Due to presence of many blood vessels, melanomas in this region often spread, mostly to the liver. Since the choroid is located at the back of eye, tumors in this region are harder to spot during self-examination.
This is the part that controls the opening and closing of the pupil. It is colored and can therefore be easily seen when looking at a mirror. Coloration indicates presence of melanocytes, the same cells in which melanoma originates. When malignancy starts in this part, it appears as a slow growing small lump which often doesn’t spread.
This part is made up of fibrous tissues which expand and contract. The movements are responsible for how the iris makes the pupil larger or smaller in response to amount of light entering the eye. When tumors grow in this region, they tend to gain a lot of mass and often spread.
Any melanoma that develops in these regions is referred to as uveal melanoma.
Uveal melanoma symptoms
Uveal melanoma symptoms are in most cases rare especially when tumors are still in their early stages. This is one of the reasons why the disease is fairly dangerous. In fact, early melanomas in eye are caught by opticians during eye tests. See pictures of melanoma in eye for illustration. When symptoms occur; they may include;
- dark spotted iris
- inability to see the periphery
- abnormal positioning of the pupil or iris
- seeing shadows or flashing lights
- blurry vision or complete vision loss
These symptoms do not necessary indicate a melanoma in the uveal. When they do, it mostly means that the disease has not spread. Melanomas that have spread produce the following symptoms;
- Multiple swollen lymph nodes, especially ones behind ear and on neck. They indicate spread to the lymphatic system.
- Reduced liver function, vomiting, nausea and loss of weight without trying to. These are symptoms of tumor in liver.
- Chronic cough, chest pain and blood in cough. These are signs of tumor in lungs.
- Loss of bone density which results in bone pain and frequent fractures. They are signs of tumor in bones.
Uveal melanoma causes
The exact cause of this disease is still not fully understood. Below are common risk factors;
- Age – people who are older than 50 years appear to be at a higher risk of developing this cancer.
- Exposure to UV radiation – many melanomas are thought to be encouraged by exposure to artificial or natural UV radiation. Melanoma on finger, foot or hand is an exception.
- Fair skin – fair skinned people often develop conditions related to sunburn and consequential damage of DNA.
- Having blue eyes – it has been noted that blue eye pigmentation in a way predisposes people to uveal melanoma.
- Dysplastic nevi syndrome – this is a condition that results in many irregular but benign moles. It is however very unlikely that the condition will cause uveal melanoma. Dysplastic nevi are more closely associated with melanoma on hand than in eyes.
Note that risk factors are not guaranteed causes of a disease. Presence of a risk factor only raises the probability of a disease occurring.
Uveal melanoma staging
After scans and diagnosis tests, uveal melanoma staging is done on basis of the reports. Ocular melanoma prognosis is usually directly dependent of staging results. Traditional staging classifies tumors in four stages, stage I, II, III and four. The first two stages represent tumors that have not spread but may have penetrated into the dermis. The latter two stages represent tumors that have either invaded the lymphatic system or distant organs.
Uveal melanoma staging can also be done using the TNM system. In this case, the T stands for tumor and describes its size and location. N stands for node and explains whether malignancy has spread to lymph nodes and the number of nodes that have been invaded. M stands for metastasis. It describes the extent to which malignancy has invaded distant organs.
TNM system is quite complex and very precise. In fact, tumors in ciliary body are not described the same way ones in the choroid or iris are when using this system.
Generally, 3 and 4 are the most advanced melanoma stages.
Uveal melanoma diagnosis
A number of tests to confirm uveal melanoma diagnosis are available. They include;
Eye examination during this test, the doctor will physically check for tumors in the eye. Eye drops meant to dilate the eye are often used prior to examination. A bright light may be shown inside eye or a magnifying lens be used for better view.
Ultrasound produces pictures of inside eye, including the back part of eye on an ultrasound monitor using sound waves. If a tumor is present, it will be detected by the waves.
This procedure is very effective especially for tumors in the choroid. A fluorescent dye is injected into arm. Rapidly sequential pictures are then taken as the dye circulates in blood vessels of the eye. Sometimes, a green dye is used.
A small uvea tissue is extracted and observed under a microscope. Although excisional biopsy is most effective, it is not always necessary. Some oncologists only go for Incisional biopsy. Once a melanoma has been removed, another form of biopsy may be taken to check if local lymph nodes have been invaded. In this case, a dye will be injected where the tumor was removed. It will then be traced as it reaches local lymph nodes.
Uveal melanoma treatment
Most of the available treatment options for uveal melanoma are not much different from other cancer treatments. They include;
Many tumors are removed with surgery. For uveal melanomas, excisional surgery is usually the best option for small tumors. Surgery can also be done to get rid of the entire eye if tumors are very large. After the operation, an artificial eye will be fixed to replace the removed one.
Radiotherapy uses X-rays to destroy harmful cells. It is rarely used alone for complete removal of tumors. Often, radiotherapy is used to reduce pain from spreading tumors as well as destroy malignant tissues that may have been left accidentally after surgery. Since X-rays can easily penetrate keratin tissues, radiotherapy is often used against subungual melanoma symptoms.
This is use of drugs to destroy cells with a tendency to divide rapidly. The drugs may be injected directly into the tumor or administered systematically. Chemo has a main disadvantage of destroying healthy cells too.
Melanoma immunotherapy is use of drugs to boost the immune system’s ability to fight cancer cells. It is quite effective but with several side effects. Immunotherapy proves necessary such as when treating anal melanoma or liver melanoma which has spread from the uvea.
In this case, drugs that specifically target cancer cells are used. It is a recent introduction in treatment options for cancer.
This is a more outdated treatment option for uveal melanoma. A very cold substance is used to stop biological functions of malignant cells thus leading to their death. Chemotherapy eye drops are often administered afterwards.
Uveal melanoma prognosis
Uveal melanoma prognosis is best for in situ tumors. In fact, melanoma in situ prognosis is always best for all melanomas. It depends on the following factors;
- Tumor status – large tumors are harder to get rid of. The same can be said about tumors located in more delicate sections of the uvea. Tumors that have spread or recurred after initial treatment may show resistance to drugs.
- Age of the patient – older people usually have lower metabolic rates and hence poor recovery from wounds. Complex operations and use of crude drugs in such people is mostly not an alternative.
- Hereditary factors – if a uveal melanoma has been caused by alteration in some genes, there are chances that it will come back regardless of an initial effective treatment. This therefore calls for close monitoring after treatment.