Proton beam therapy treatment for cancer

Proton beam therapy is a type of radiotherapy. Radiotherapy uses high energy X-rays whereas proton beam therapy uses a beam of high energy protons. Protons are small parts of atoms.  

You can find out more about radiotherapy on our information page.

One of the benefits of proton beam therapy is that because the beam is so accurate it sometimes means they can give you a higher dose of treatment as it won’t impact the tissue around the area being treated.   

This also means you might have fewer long-term side effects as a result of the treatment.  

Proton beam therapy can be used to deliver radiation to very specific parts of the body to treat cancer. The high energy protons target and destroy the cancer cells. This means very little or no radiation affects normal tissue around the area being treated.  

Proton beam therapy is given using a machine called a ‘gantry’. The machine rotates 360 degrees around you which means it can accurately aim the proton beam at the area which needs to be treated.   

Proton beam therapy isn’t suitable for all types of cancer and at the moment it can only be used on a limited range of cancer types. Proton beam therapy is generally used for solid tumour cancers such as brain tumours and some types of sarcoma and primary bone cancer. 

Your consultant will talk to you about whether proton beam therapy is an option for you, and they’ll refer you if it’s a good option for you.  

How long your specific treatment programme takes will depend on the area of your body that’s being treated. You’ll be given more information about this during your assessment visit and you can ask any questions you might have about how long it will take.  

Every course of proton beam therapy is different depending on your diagnosis and the type of cancer that is being treated. The minimum course for proton beam therapy is usually three weeks and the maximum course is six and a half weeks. During this time you will have treatment five days a week. You’ll have your treatment on weekdays, not weekends.  

The tests you have before you start proton beam therapy will depend on what your consultant asks for. Some of the tests you have might include CT scans, MRI scans, PET scans, a lumbar puncture and a kidney scan (renogram). Depending on your diagnosis and what other treatment types you’ve had your sight, hearing and teeth may also be checked.   

Depending on the part of your body that is being treated you might have to wear a mask. This is to make sure you stay very still during treatment and it also means they can accurately treat the exact same area every time you have treatment. You can find out more about masks and how they are fitted here.  

You won’t feel any pain while you’re having proton beam therapy. Nothing will touch any part of your body directly. The machine will make some noise and there is sometimes a smell which can be a bit unpleasant. Sometimes people see flashing lights before their eyes during the treatment. Not everyone will experience these but they are all completely normal and safe side effects of the treatment. If you have any questions about what it will be like in the room during your treatment you can always ask your care team.  

The type of side effects you experience will depend on which part of your body is being treated. Your care team should explain any potential side effects before your treatment starts.  

A lot of the common side effects of proton beam therapy are similar to those you might experience after having external radiotherapy. They can be quite mild and don’t last too long, but they can still be unpleasant and uncomfortable. Short-term side effects settle down typically between 6-8 weeks.  

Side effects can include:  

• Sore skin: this will only be in the area you had treated. Your skin might feel dry and itchy and may also peel. It can feel similar to sun burn  
• Hair loss: it’s important to note that you’ll only lose hair in the area of your body that you have had treated  
• Fatigue: you will be using a lot of energy to help your body recover so there’s a chance you’ll feel really tired after having proton beam therapy. Traveling to and from hospital every day can also make you feel tired. Find out more about fatigue here  
• Nausea and diarrhoea: you might feel sick or have diarrhoea after treatment. If you have either of these side effects you can speak to your doctor who should be able to give advice on what to do  
• Appetite: treatment might also affect your appetite too. If you’re not feeling great then you might not want to eat anything either. Try and eat small things when you can to keep your energy levels up   

Sometimes, cancer treatments can have side effects that don’t get better once the treatment has finished. These vary depending on where your cancer is but, if you’re worried, talk to your doctor or nurse about possible long-term side effects before you start any treatment.  

You can find out more about side effects on our radiotherapy information page and there’s more information about any possible late effects here 

You’ll be seen weekly by your consultant and other members of your care team. It’s important to let them know how you’re feeling and any side effects you’re experiencing. They will be able to prescribe medication that can help with some of your symptoms like anti-sickness medication, pain relief or certain creams for sore skin.   

Exercise when you feel up to it and rest when you feel you need to. Try and keep up a healthy lifestyle so you can avoid any breaks in treatment.  

You can also ask to be put in touch with other support staff and allied health professionals who can help you. Allied health professionals work both in and out of hospitals and in some cases might come to your home. They can help with movement or mobility difficulties, visual problems, advice on what to eat and nutrition, communication and everyday activities.   

You can find out more about each allied health professional role on the NHS website.   

If you’re having sex you should use barrier types of contraception, like condoms and dams, to protect you and your partner and to also stop you getting pregnant. You need to let your care team know if you think you might be pregnant as this could affect your treatment.    

You might not feel comfortable talking to your care team about sex but it’s important to remember this is their job and they’ve probably had these conversations lots of times before! They should be able to help you with any questions you might have. 

Proton therapy can affect fertility, but it depends on the part of the body that is being treated. You should speak to your consultant or doctor to find out what impact it may have on your fertility. 

You can find out more about how cancer treatment can affect your fertility on our fertility information page.

You will be on your own for scans and treatment but there will be staff nearby most of the time. There will also be staff watching you all the time on monitors and they can speak to you through the intercom. All you need to do is raise your hand to show you want to speak to someone. They will either be behind a glass shield in the room or down a small corridor during your treatment. 

There are currently two proton beam therapy centres in the UK. They are at The Christie in Manchester and University College Hospital in London (UCLH). 

If you’re referred to The Christie or UCLH for proton beam therapy the teams will be able to answer any questions you have about travelling to and from appointments and whether there is any funding available for travel costs, or accommodation. 

You can find more information about having proton beam therapy at The Christie and at UCLH on their websites, linked below: 

• The Christie 
• UCLH 

You can download our factsheet ‘Common questions about proton beam therapy’ here: 

This page was reviewed in August 2026. It will be reviewed again in August 2029.