Ocular melanoma (melanoma of the eye)
This information is about a rare type of cancer called ocular melanoma (melanoma of the eye). You may also find it helpful to read our general information about malignant melanoma.
We hope this information answers your questions. If you have any further questions, ask your doctor or nurse at the hospital where you are having your treatment.
Ocular melanoma is melanoma of the eye. It's a cancer that develops from cells called melanocytes. Melanocytes produce the dark-coloured pigment melanin, which is responsible for the colour of our skin. These cells are found in many places in our body, including the skin, hair, and lining of the internal organs, including the eye.
Most melanomas begin to grow in the skin, but it's also possible for a melanoma to begin in other parts of the body, such as the eye.
Melanoma can develop in one of several places within the eye. Uveal melanoma is the most common type of ocular melanoma. This occurs along the uveal tract of the eye, which includes the choroid, ciliary body and iris.
The choroid is part of the lining of the eyeball. It's dark-coloured (pigmented) to prevent light reflecting around the inside of the eye. The ciliary body extends from the choroid and focuses the eye by changing the shape of the lens. The iris is the clearly visible, coloured disc at the front of the eye, which controls the amount of light entering the eye. All these structures are coloured with melanin.
Melanoma can also occur in the thin lining over the white part of the eye (the conjunctiva) or on the eyelid, but this is very rare. This is known as conjunctival melanoma.
Ocular melanoma is the most common type of cancer to affect the eye, although it's still quite rare. Between 400-450 new cases of eye cancer (including ocular melanoma) are diagnosed in the UK each year. The incidence of ocular melanoma increases with age, and most cases are diagnosed in people in their 50s.
Causes of ocular melanoma
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This is a rare type of tumour and the exact cause is unknown. It's known that exposure to ultraviolet (UV) rays, either from the sun or sunbeds, increases the risk of developing melanoma of the skin. People whose skin burns easily are most at risk - people with fair skin, fair or red hair, and blue eyes. However, it's not yet known whether there is any link between UV ray exposure and the development of melanoma of the eye.
Ocular melanoma may be more common in people who have atypical mole syndrome (also called dysplastic naevus syndrome). People with this condition often have over 100 moles on their body, some of which are abnormal in size and shape, and have a greater risk of developing a melanoma of the skin.
Symptoms of ocular melanoma include blurred vision, and seeing flashing lights and shadows. However, often it doesn't cause any symptoms and may be diagnosed by an optician during a routine sight test.
These symptoms are common to other conditions of the eye, but you should tell your doctor or optician if you notice them. It's usually possible for an eye specialist (ophthalmologist) to diagnose these tumours quite simply and painlessly. Occasionally, a small sample of tissue will need to be taken and examined (a biopsy), to confirm a diagnosis.
How ocular melanoma is diagnosed
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A number of tests may be done to diagnose ocular melanoma, including:
A small, handheld lens (ophthalmoscope) is used to look at the inside of the eye.
A small device that produces sound waves is moved over the skin around the eye area. The echoes are then converted into a picture by a computer.
Colour fundus photography
Photographs of the back of your eye (fundus) are taken, which can help to show what the tumour looks like before and after treatment. For the test, you'll have eye drops to make your pupils dilate, and a special camera will be used to take a picture of the fundus.
Sometimes, a small sample of tissue may be taken from the suspicious area and examined under a microscope. However, this is not usually necessary because most ocular melanomas have a distinctive appearance and can usually be recognised easily from x-rays and scans. A biopsy will be done using either a local or general anaesthetic.
Less common tests
Other tests that are used less often include:
A special dye called fluorescein is injected into a vein in the arm. In a few seconds, the dye travels to the blood vessels inside the eye. A camera with special filters that highlight the dye is used to photograph the fluorescein as it circulates through the blood vessels in the retina and choroid.
CT (computerised tomography) scan
A CT scan takes a series of x-rays that build up a three-dimensional picture of the inside of the body. The scan is painless and takes 10-15 minutes. CT scans use a small amount of radiation, which would be very unlikely to harm you or anyone you come into contact with. You'll be asked to not eat or drink for at least four hours before the scan.
You may be given a drink or injection of a dye, which allows particular areas to be seen more clearly. This may make you feel hot all over for a few minutes. It’s important to let your doctor know if you are allergic to iodine or have asthma, because you could have a more serious reaction to the injection.
This is a combination of a CT scan and a PET (positron emission tomography) scan, which uses low-dose radiation to measure the activity of cells in different parts of the body. PET/CT scans give more detailed information about the part of the body being scanned. They are a newer type of scan, and you may have to travel to a specialist centre to have one.
You won't be able to eat for six hours before the scan, although you may be able to drink. A mildly radioactive substance is injected into a vein, usually in your arm. The radiation dose used is very small. The scan is done after at least an hour’s wait. It usually takes about 30 minutes and you should be able to go home after the scan.
MRI (magnetic resonance imaging) scan
This test is similar to a CT scan, but uses magnetism instead of x-rays to build up a detailed picture of areas of your body.
A number of different treatments are used for ocular melanoma. The treatment you will have depends on the size, cell type and position of the tumour, and on other factors, such as your general health and level of vision in both eyes. The aim of treatment is to destroy the cancer cells, stop the cancer coming back, and save as much of your vision as possible.
Some treatments for melanoma of the eye are very specialised, and are only available at a few hospitals in the UK, so you may have to travel to one of these centres for your treatment.
This type of treatment uses high-energy rays to destroy the cancer cells, while doing as little harm as possible to normal cells. Radiotherapy may be given either from outside the body (external radiotherapy) or from within the body (internal radiotherapy). Radiotherapy may be the only treatment, or it may be given after surgery. Recent developments in radiotherapy mean that it can be possible to preserve sight in the eye, either completely or partly.
External radiotherapy In external radiotherapy a beam of radiation is directed at the area of the tumour. The treatment is normally given as small doses, called fractions, over a few days.
A cyclotron is a particular type of radiotherapy machine specifically used to treat eye tumours. It directs a proton radiation beam precisely at the affected area, causing as little radiation exposure as possible to the surrounding healthy eye tissue. Before the treatment, you'll have a minor operation to attach small metal tags to various parts of the eye. The tags act as markers for the radiation beam.
This treatment is given using a radioactive source called a plaque. The plaque is a small disc that is placed over the position of the tumour during an operation. It is left in place, usually for between 1-4 days, until the total dose of radiation has been given. This normally involves a stay in hospital of up to a week.
Usually the operation is carried out under a general anaesthetic. Occasionally, a local anaesthetic is used with sedation if you're not fit enough to have a general anaesthetic. Certain precautions need to be taken while the plaque is in your eye. You'll need to stay in one room and each member of staff and your visitors will be allowed in for only a short time each day. This is to reduce any unnecessary exposure to radiation. No precautions will be necessary once the radioactive source is removed, as the radiation will no longer be present.
Transpupillary thermotherapy (TTT)
This can be used to treat very small ocular melanomas, or as an additional treatment after radiotherapy. The tumour is heated with a special type of laser beam. Cancer cells are more susceptible to heat than normal cells and so will be destroyed. You may need several treatments.
This will be done using a local anaesthetic and sedation to relax you.
This may involve removing just the tumour, a small part of the eye, or sometimes the whole eye. The type of surgery you have depends on the size and position of the tumour.
Your surgeon will try to preserve your eye. However, if the cancer is large or in a difficult position, or if the eye is already blind and painful, the most appropriate treatment for you may be to remove the whole eyeball. This is called enucleation. Your surgeon will recommend this operation only if it's absolutely necessary.
For many people this suggestion can be quite shocking, and you may need to have a lot of discussions with your doctor before you decide to go ahead. You can have an artificial eye (prosthesis) made that matches your remaining eye. You may also have an implant that makes your artificial eye move realistically.
The thought of having any type of surgery to your eye can be frightening, and you may have worries about how your sight will be affected. You can talk your concerns over with your eye surgeon or specialist nurse - they will answer any questions before your operation.
Eye surgery will be carried out by a specialist surgeon, and you’ll be given either a general anaesthetic or a local anaesthetic and sedation.
Melanoma affecting the conjunctiva, which is the thin lining over the white part of the eye or the inside of the eyelids, is rare. Some conjunctival melanomas may be due to sun exposure. In this way, they are like melanomas of the skin, which are more common in people with fair colouring and light eyes who burn more easily in the sun.
However, most conjunctival melanomas develop from a very rare condition called primary acquired melanosis (PAM), which causes brown or dark patches (pigmentation) on the conjunctiva. Sometimes the melanoma will develop from an existing freckle or mole on the conjunctiva. You should check any new pigmentations or changes to an existing area with your doctor.
A conjunctival melanoma is diagnosed by taking a small sample of cells from the pigmented area (a biopsy). If a melanoma is diagnosed, you'll have a small operation to remove the abnormal area and a margin of surrounding healthy cells.
After surgery you may have a treatment called cryotherapy. This freezes the area to kill any melanoma cells that may have been left behind after surgery. Sometimes radiotherapy may be used instead of cryotherapy. This involves brief daily treatments over a week or so, using a small radioactive disc shaped like a contact lens. Occasionally, eye drops containing chemotherapy drugs may be used. This is known as topical chemotherapy.
If the melanoma is quite large, it may sometimes be necessary to completely remove the conjunctiva as well as the eyeball. This is a rare operation called an orbital exenteration. After this type of surgery you may have a facial prosthesis (false part), that covers the eye socket and contains false lids, lashes, and an artificial eye. The eye will not be able to move or open or close. The prosthesis can be mounted on to a pair of glasses, or fixed to your face with a special glue. Alternatively, studs may be fixed into the bone around the eye socket, although this is rare.
The thought of this operation can be very distressing, and you may need to spend time talking it through with your doctor or specialist nurse, who can answer any questions you may have. There will be support available to help you cope during this difficult time – from doctors, counsellors and patient support groups.
Research into treatments for ocular melanoma is ongoing and advances are being made. Cancer doctors use clinical trials to assess new treatments. Before any trial is allowed to take place, an ethics committee must approve it and agree that the trial is in the interest of patients.
You may be asked to take part in a clinical trial. Your doctor will discuss the treatment with you so that you have a full understanding of the trial and what it involves. You may decide not to take part, or to withdraw from a trial at any stage. You'll still receive the best standard treatment available.
Follow-up for ocular melanoma
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After your treatment is completed, you'll have regular check-ups and possibly scans or x-rays. It may be helpful to discuss with your doctor how often these scans will be. These will probably continue for several years. If you have any problems, or notice any new symptoms between these times, let your doctor know as soon as possible.
Ocular melanoma can sometimes spread to other parts of the body - most often to the liver, but also to the lungs and bones. It's important to let your specialist know if you notice any new symptoms, wherever they are in the body, as it may be possible to have further treatment.
During your diagnosis and treatment of cancer you're likely to experience a number of emotions, from shock and disbelief to fear and anger. At times, these emotions can be overwhelming and hard to control. It's natural and important to be able to express them.
Each individual has their own way of coping with difficult situations - some people find it helpful to talk to friends or family, while others prefer to seek help from people outside their situation, and some people prefer to keep their feelings to themselves. There is no right or wrong way to cope, but help is available if you need it. You may wish to contact our cancer support specialists for information about counselling.
This section has been compiled using information from a number of reliable sources, including:
Ocular Melanoma. UpToDate. www.uptodate.com (accessed September 2012).
Raghavan, et al. Cancer: Principles and Practice of Oncology. 7th edition. 2005. Lippincott Williams and Wilkins.
Raghavan, et al. The Textbook of Uncommon Cancers. 3rd edition. 2006. Wiley.
Singh, et al. Clinical Opthalmic Oncology. 2007. 1st edition. Saunders Elsevier.
Souhami, Tobias. Cancer and its Management. 5th edition. 2005. Oxford Blackwell.
Thank you to Dr Gordon Hay, Clinical Fellow in Ocular Oncology, and all of the people affected by cancer who reviewed this edition. Reviewing information is just one of the ways you could help when you join our Cancer Voices network.