Having external radiotherapy for eye cancer

External radiotherapy means having radiation from a machine outside the eye. It only treats the area of the body the radiation is directed at.

When you might have it

You may have external radiotherapy on its own. Or you might have it with other treatments such as surgery and chemotherapy. The treatment you have and the order you have it depends on the type and size of the cancer. The types of eye cancers that are treated with external beam radiotherapy include:

Eye melanoma

Radiotherapy is often used to treat melanoma of the eye. Internal radiotherapy (brachytherapy) is usually used for small or medium sized eye melanomas. If internal radiotherapy is not suitable for your cancer, you might have external radiotherapy. 

You may have surgery before radiotherapy. This depends on the size of the cancer and where it is. Having more than one type of treatment could mean that you can keep some, or all of your sight.

Eye lymphoma

You usually have external beam radiotherapy for:

• ocular adnexal lymphoma

• choroidal lymphoma

• vitreoretinal lymphoma 

Your doctor may suggest radiotherapy treatment similar to that used for non-Hodgkin lymphoma. Radiotherapy for eye lymphoma can include both eyes if there is a high chance of the cancer being present in both eyes. 

Some eye lymphomas can spread to the brain. In this situation, you may have radiotherapy to the eyes and brain. It can clear the cancer in the eye and also help to stop it coming back in the brain or spinal cord.

You may have chemotherapy as well as radiotherapy depending on the type and location of the lymphoma.

Lacrimal gland cancer

You might have external beam radiotherapy following an operation to remove your lacrimal gland cancer. This aims to treat any cancer cells left behind and reduce the risk of it coming back.

Sometimes it is possible to remove the lacrimal gland cancer, without removing the whole eye. 

Squamous cell skin cancer

You may have external radiotherapy on its own for squamous cell skin cancer of the eyelid when surgery is too risky. Or you might have radiotherapy after surgery in one of the following situations:

• your cancer has spread to lymph nodes or nerves

• there is a high risk that it may come back

Types of external radiotherapy

There are different types of machines that give external radiotherapy. Some are better for treating cancers on the surface of the eye. Others are best for eye cancers that are deeper in the socket. Your radiotherapy specialist (clinical oncologist) carefully chooses the machine that is right for your type of eye cancer.

Types of external radiotherapy you may have for eye cancer are:

• stereotactic radiosurgery

• proton therapy

Stereotactic radiosurgery

Stereotactic radiosurgery uses lots of small thin radiation beams. They target a large dose of radiotherapy on the cancer. You may have a single treatment, or up to 5 treatments. 

As treatment is targeted at the cancer, there is less radiation to healthy tissue and fewer side effects. Although it’s called radiosurgery there is no surgery involved.

There are several types of machines that deliver this treatment:

• Linac (linear accelerator)

• Gamma Knife

• CyberKnife

Proton therapy

Proton therapy machines treat eye cancers using a type of radiation known as proton radiation. The proton beams are aimed precisely at the cancer. This type of radiation reduces the risk of damage to the surrounding healthy eye tissue.

You usually have treatment every day for 4 to 5 days.

The radiotherapy room

Radiotherapy machines are very big and could make you feel nervous when you see them for the first time. The machine might be fixed in one position. Or it might rotate around your body to give treatment from different directions. The machine doesn't touch you at any point.

Before your first treatment, your ​radiographers​ will explain what you will see and hear. In some departments, the treatment rooms have docks for you to plug in music players. So you can listen to your own music while you have treatment.

During treatment

Stereotactic radiosurgery

On the day of your treatment, your radiographer takes you to the treatment room. When you are lying comfortably on the couch your head frame or mask is fitted. The radiographers leave the room before treatment starts. Although you are alone, they can see you from the control room. 

Once everything is in place, the couch slides into the machine and the treatment begins. You are awake the whole time. 

You won't feel anything while you are having treatment. It can take a few hours. Before you start your radiographer will tell you exactly how long your treatment takes.

Proton therapy

You might have local anaesthetic eye drops just before your treatment. This helps reduce the amount of eye movement. Each treatment takes about 30 seconds, but the appointment takes around 30 minutes. In this time the radiographer makes sure: 

• you are in the correct position

• you have the correct dose to the right part of the eye

You are in the room on your own during treatment, and you don’t feel or see anything. Sometimes you can hear a hum or buzz while you have it.  

After each appointment, a pad is placed over your eye to protect it until the anaesthetic wears off.

You won't be radioactive

External radiotherapy does not make you radioactive. It's safe to be with other people throughout your course of treatment, including pregnant women and children.

Side effects of treatment

Radiotherapy for eye cancer has some side effects. The side effects you might have depend on which part of your eye has been treated.

Find out more about the side effects of radiotherapy to the eye