Proton beam therapy

Proton beam therapy is a type of external beam radiotherapy. 

Proton beam therapy is only suitable for a small number of people with certain cancer types. It is used to help reduce the risk of long-term side effects that can sometimes develop after standard radiotherapy. It can also be used to treat cancers that are close to important parts of the body.

These cancers may be difficult to treat with standard external beam radiotherapy.

Proton beam therapy is given using specialised equipment that is not available in all UK hospitals. You may be referred to a specialist hospital if your cancer doctor thinks it is a suitable treatment for you.

Proton beam therapy is not suitable for everyone. It can be used to treat children, teenagers, young adults and some adults (see below).

Proton beam therapy may be given on its own or in combination with other treatments. For example, it may be given with surgery, standard radiotherapy and chemotherapy.

Proton beam therapy is still quite a new treatment in the UK. Research is needed to find out more about its long-term benefits and side effects, and to compare it with standard treatments.

It is also important to remember that when treating most types of cancer, standard radiotherapy is a very effective and safe treatment. Standard radiotherapy can cause side effects, but they usually get better when the treatment has finished.

Your healthcare team will give you more information if proton beam therapy is suitable for you. It may be given as part of a clinical trial. We have more information about clinical trials.

Proton beam therapy may be used to treat children, teenagers and young adults. It can be better for these groups than standard radiotherapy, because it:

• reduces the risk of damage to developing or growing cells
• can help reduce the risk of long-term effects on normal cells, such as to the brain or bones.

It is used to treat most tumours that need curative radiotherapy in young people. Examples include:

• brain tumours
• types of soft tissue sarcoma, such as rhabdomyosarcoma
• types of primary bone cancer, such Ewing’s sarcoma
• some types of cancers in the pelvic area
• some types of cancers in the head and neck area.

Proton beam therapy can also be used to treat adults with cancers:

• that can be difficult to treat because of where they are in the body
• that are in a position where the side effects of standard radiotherapy would cause serious problems
• where there is a high risk of late side effects from standard treatments
• that do not respond well to standard radiotherapy and would need a very high dose of treatment to be effective.

It can also be used to treat cancers that are close to important structures. These can include:

• cancers affecting the base of the skull
• cancers affecting the spine
• some types of cancers in the pelvis
• some types of head and neck cancers

Low-dose proton beam therapy is also commonly used to treat cancers affecting the eye, such as ocular melanoma.

Proton beam therapy may sometimes be used to treat other cancers.

You usually have proton beam therapy as an outpatient. The number of treatments you have will depend on the type of cancer you have. You usually have 1 session of treatment a day from Monday to Friday, with a rest at the weekends. The treatment normally lasts for 3 to 8 weeks. This is called a course of treatment. Your cancer doctor, specialist nurse or radiographer will explain the treatment plan to you.

Each appointment usually takes about 30 to 60 minutes, although you may be in the department for longer. The treatment can take up to 30 minutes to deliver. Most of the appointment is spent getting you into the correct position and doing checks.

Before your treatment, the radiographers help you on to the treatment couch and position you carefully. They also adjust the height and position of the couch. It is important you are comfortable, as you have to lie as still as possible during the treatment. Tell the radiographers if you are not comfortable.

Young children who are having proton beam therapy may have a general anaesthetic to help them lie still during each treatment. The anaesthetic only lasts for a short time. They may also have an anaesthetic if they are very anxious. Sometimes a play specialist comes to the treatment session to help them keep calm and still.

Before each treatment, you have a CT scan or x-rays in the treatment room. This makes sure you are in the correct position.

When you are in the correct position, the radiographers leave the room and you start your treatment. There is a camera, so they can see you from outside the room. There is also an intercom, so you can talk to them if you need to during your treatment.

You may have more CT or MRI scans during your course of treatment. This is to make sure the treatment is always accurately aimed at the cancer. The radiographers will tell you if you need to have more scans.

Proton beam therapy machines have a part called the gantry. This moves around you to give the treatment from different angles. Or sometimes the treatment couch moves around and the machine stays still.

The movements are controlled by the radiographers from outside the room. The radiotherapy machine does not touch you. The treatment itself is painless.

When your treatment session has finished, the radiographers will come and help you off the treatment couch. It is important to wait until they tell you it is okay to move. You can usually go home when the treatment is finished.

Proton beam therapy does not make you radioactive. It is safe to be with other people, including children, throughout your treatment.

Most types of radiotherapy cause side effects that develop during treatment and slowly improve after treatment has finished. But sometimes side effects do not go away, or they start months or years after treatment has ended. These side effects are called:

• long-term effects – if they begin during treatment, or shortly after treatment has ended, and do not go away
• late effects – if they begin months or even years later, as a delayed response to treatment.

The possible late effects of proton beam therapy depend on the area of the body that is treated. Your cancer doctor, specialist nurse or radiographer can give you more information.

Children may get different late effects to adults. This is because they are still growing. Children and teenagers are more likely than adults to develop late effects after proton beam therapy.

At the moment, proton beam therapy is only used to treat a few types of cancer. We only know about some of the potential late effects of treatment for these cancers.

More research is needed to find out if proton beam therapy causes late effects when used to treat other types of cancer. If you are worried about the risk of late effects, talk to your cancer doctor or specialist nurse.

As with standard radiotherapy treatment, proton beam therapy can increase the risk of developing a second cancer. But the risk of a second cancer is lower with proton beam therapy than with standard radiotherapy treatment.

This risk is far less than the benefits of treating the first cancer with radiotherapy. If you are worried about your risk of developing a second cancer, talk to your cancer doctor.

Proton beam therapy may cause fewer side effects for some cancers, but we do not know if it is better than standard radiotherapy or other treatments. Proton beam therapy has only been used to treat a few different types of cancer in the UK.

More research is needed before we know if proton beam therapy is as good as, or better than, standard radiotherapy or other treatments.

The benefits of proton beam therapy include:

• It can be used to treat cancers that are close to important parts of the body. These cancers can be difficult to treat with standard radiotherapy.
• It may cause fewer side effects than standard radiotherapy. This is because there is less damage to normal cells.
• It may be possible to give higher doses of treatment, without increasing side effects.
• It may help reduce the risk of developing long-term or late side effects.
• It may help reduce the risk of developing a second cancer.

Disadvantages of proton beam therapy include:

• It is only suitable for certain types of cancer.
• The 2 NHS proton centres in the UK are in London and Manchester. If you live far away from these you may need to stay closer for your treatment.
• The therapy is much newer than standard radiotherapy and more research is needed to understand the differences.

  For example, we do not know the differences between possible late effects of standard radiotherapy and proton beam therapy.

• People treated with proton beam therapy will still have some side effects.

Your cancer doctor or specialist nurse will talk to you about your treatment options. If proton beam therapy is suitable for you they will talk to you about the possible benefits and disadvantages. This will help you decide whether to have proton beam therapy or another type of treatment.