Eye cancer (ocular melanoma)

Eye cancer is rare.  About 850 people are diagnosed with eye cancer in the UK each year.  There are different cancers that can affect the eye. Eye melanoma is the most common type. It is also called ocular melanoma.

Melanoma s a cancer that develops from cells called melanocytes. Melanocytes give our skin its colour, and melanoma usually develops in the skin. But because there are melanocytes in different parts of the body, melanoma can start in other places, such as the eye.

This information is about eye melanoma.

The eye is made up of different layers of tissue and filled with a clear jelly. Different parts of the eye work together to help us see.

The conjunctiva is a thin, clear lining that covers and protects the white outer surface of the eye and the inside of the eyelids.

The uvea is the middle layer around the eyeball. It controls how light comes into the eyeball and helps the eye to focus. It also makes a fluid around the lens (the clear inner part of the eye). This fluid keeps your eye healthy.

The uvea includes the following parts:

• The iris, which is the coloured disc at the front of your eye. It controls the light entering the eye.
• The ciliary body, which makes the fluid around the lens. This keeps your eye healthy and able to focus.
• The choroid, which lines the back of the eye. It contains blood vessels which provide nutrients to the retina.

There are 2 main types of eye melanoma:

• Uveal melanoma, which starts in the uvea. This is the most common type of eye melanoma. It usually affects the choroid or sometimes the ciliary body. It rarely affects the iris.
• Conjunctival melanoma, which starts on the conjunctiva. This is a rarer type of eye melanoma.

Doctors do not know what causes eye melanoma. But there are risk factors that can increase the chance of developing it.

Uveal melanoma is more common in people with:

• skin that burns easily
• fair or red hair
• blue eyes.

It is rare in people with brown eyes or if you are Black or Asian.

The main risk factor for skin melanoma is exposure to ultraviolet rays (UV rays). But it is not clear whether there is a link between UV ray exposure and uveal melanoma. There is some evidence linking conjunctival melanoma to exposure to UV rays through sunlight, sunbeds or sunlamps.

Eye melanoma is more common in people who have atypical mole syndrome. People with this condition usually have more than 100 moles on their body.

Conjunctival melanoma usually develops from a rare condition called primary acquired melanosis (PAM). This causes many brown or dark patches (pigmentation) on the conjunctiva, usually in one eye. PAM can be monitored so that any signs of it changing are found early and treated.

Sometimes the melanoma develops suddenly. But it can also develop from an existing freckle or mole on the conjunctiva.

The results of your tests help your doctors find out more about the size and position of the cancer and whether it has spread. This is called staging. Knowing the stage helps your doctors plan the best treatment for you.

The TNM staging system is commonly used for eye melanoma. TNM stands for tumour, nodes, metastases.

T describes the size of the tumour and whether it has grown into other parts of the eye (intraocular) or areas outside the eyeball (extraocular). It also measures the thickness and width of the eye melanoma.

N is whether the cancer has spread to lymph nodes near the eye.

• N0 means the cancer cells are not in the nearby lymph nodes.
• N1 means there are cancer cells in the lymph nodes. It is more common for conjunctival melanoma to spread to nearby lymph nodes.

M is whether the cancer has spread to another part of the body. This is called metastatic cancer.

• M0 means the cancer has not spread.
• M1 means the cancer has spread to other organs, such as the liver.

Your doctor or nurse may describe the tumour as small, medium or large. Or they may describe it as:

• early or localised – this is eye melanoma that has not spread outside the eye
• advanced – this is eye melanoma that has spread to areas outside the eye, or to the liver or lungs.

Advanced eye cancer is when the cancer has spread to another part of the body or comes back after treatment. The treatment you have will depend on where it has spread to and treatments you have already had.

If melanoma comes back in the eye, it is called a local recurrence. This usually needs to be treated with surgery to remove the eye. If conjunctival melanoma comes back in the same area, you may have surgery to remove the lymph nodes in the neck.

If uveal melanoma comes back in the liver it is called secondary liver cancer. There are different treatments that can be used.

A new immunotherapy drug called tebentafusp or Kimmtrak^® may be used to control uveal melanoma. It has been shown to help people with advanced uveal melanoma to live for longer.

Sometimes targeted drugs may be used to treat advanced conjunctival melanoma.

We have more information about treating advanced eye cancer.

We want everyone affected by cancer to feel our information is written for them.

We want our information to be as clear as possible. To do this, we try to:

• use plain English
• explain medical words
• use short sentences
• use illustrations to explain text
• structure the information clearly
• make sure important points are clear.

We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.

You can read more about how we produce our information here.