Proton beam therapy

What is proton beam therapy?

Proton beam therapy is a specialised form of external radiotherapy. Instead of x-rays (photons), it uses beams of protons. Protons can be aimed to release most of their energy at a set depth and then stop, so there is little 'exit dose' beyond the target. In the right situation this can mean less radiation to healthy tissue sitting just behind the tumour.

This is genuinely useful for certain cancers, especially in children, teenagers and young adults, and for some rare tumours sitting next to critical structures such as the brain, base of skull or spinal cord, where reducing the dose to nearby healthy tissue can lower the risk of long-term harm.

However, it is important to be honest: for the majority of cancers, proton therapy has not been shown to give better results than modern, well-delivered x-ray radiotherapy, which remains the most appropriate treatment for most people. NHS England funds proton therapy only for specific approved indications, with treatment at The Christie in Manchester and University College Hospital in London (and Clatterbridge for some eye tumours).

Proton therapy is still radiotherapy. It is not free of side effects or risks: it causes skin and site-specific reactions and tiredness like other radiotherapy. Be cautious of overseas or private clinics that market it as automatically better for cancers where the evidence does not support that.

Types, options & approaches

There may be different ways to do this. The right approach depends on the clinical question and your circumstances.

Proton therapy compared with standard (x-ray) radiotherapy

A theoretical advantage in the dose pattern does not automatically mean better outcomes. For most cancers the evidence does not show protons are better, which is why the NHS reserves them for specific situations.

Preparing for your treatment

• Ask clearly why proton therapy is being suggested for you, and whether there is good evidence it is better than standard radiotherapy for your specific cancer.
• If you are considering a private or overseas centre, ask your NHS oncology team for an honest second opinion before committing.
• Ask whether you meet the approved NHS criteria, and if not, why proton therapy is still being recommended.
• Plan for a course that may run daily over several weeks, including travel, accommodation and time off, as you may need to stay near the centre.
• For a child, discuss whether daily anaesthetic or sedation will be needed to keep still, and what that involves.
• Tell the team about all your medical conditions, medicines and any previous radiotherapy.
• Bring your scans, diagnosis details and a list of questions, ideally agreed with your existing cancer team.

What happens

Before treatment you have a planning session, usually including a planning CT scan in the treatment position and often an immobilisation device such as a mask or mould. The team uses your scans to design a plan that shapes the proton dose to the tumour.

Each treatment session involves lying still in the same position while the machine delivers the protons, usually over a few minutes of beam time with longer for careful set-up. You do not feel the radiation. A course is often given daily, Monday to Friday, over several weeks, depending on the cancer.

Young children may need a short general anaesthetic or sedation each day so they can stay completely still. Adults are usually awake. Throughout, the team checks your position with imaging to keep treatment accurate.

You are monitored during the course for side effects, which build up gradually and depend on the area treated. After the course, radiotherapy keeps acting on the cancer for weeks to months, and follow-up is arranged to assess the response.

Is this treatment right for me?

A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.

Before you decide

Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.

Comfort, sedation or contrast choices

If local anaesthetic, sedation, contrast or pain relief is used, ask what is planned, why, and what it means afterwards.

The biggest issue with proton therapy is not usually safety but appropriateness: for most cancers it is not proven to be better than standard radiotherapy, and it is still a radiotherapy treatment with real side effects. If a private or overseas provider is recommending it, ask your NHS team whether it genuinely offers you an advantage, what the evidence is for your cancer, and what standard radiotherapy would involve instead.

Published figures to discuss

Outcome and side-effect rates depend on the cancer type, stage, area treated, dose and the rest of the treatment plan, so single numbers would be misleading. The key evidence point is not a percentage but a direction: for most cancers, proton therapy has not been shown to give better outcomes than modern x-ray radiotherapy, which is why the NHS reserves it for specific situations. Side effects are those of radiotherapy in general and vary by site. We describe this honestly rather than invent precise figures; ask your oncologist for evidence specific to your cancer.

These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.

What happens afterwards

Proton therapy is a treatment, not an operation, but side effects build up over the course and can take weeks to settle afterwards, and the cancer's response is judged later. 'Recovery' is mostly about settling of side effects and waiting for planned follow-up.

• Skin redness, soreness or peeling in the treated area that settles over weeks
• Tiredness that may continue for a while after treatment ends
• Site-specific symptoms (such as a sore mouth or bowel changes) easing gradually
• No immediate change in the cancer, because radiotherapy keeps acting over weeks to months
• For children, tiredness and recovery from daily anaesthetic during the course

Aftercare

• Follow the skin-care advice you are given for the treated area, and avoid harsh products or sun exposure as directed.
• Rest when you need to, but keep gentle activity going as you are able, to help with fatigue.
• Take any prescribed medicines for side effects, such as mouth or skin care, as directed.
• Eat and drink as well as you can, and accept dietitian support if offered, especially with head, neck or abdominal treatment.
• Attend all follow-up appointments so the response and any late effects are monitored.
• For a child, keep up the planned developmental and long-term follow-up checks.
• Tell your team about any new or worsening symptoms between appointments.

• Skin-care and site-specific advice understood
• Travel and accommodation for the course arranged
• Support at home for tiredness organised
• Follow-up appointment booked
• Prescribed medicines for side effects collected
• Clear contact number for the radiotherapy team saved
• For children, long-term follow-up plan understood by the family

⚠ Get urgent help if…

• A high temperature, shivering or feeling generally unwell, which could mean an infection
• Severe or worsening skin breakdown in the treated area
• Being unable to eat or drink, or severe pain swallowing, during head or neck treatment
• Severe diarrhoea, vomiting or abdominal pain during treatment to the abdomen or pelvis
• New or worsening neurological symptoms (such as severe headache, weakness or vision changes) during treatment near the brain or spine
• Any symptom your team has told you to report straight away

Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.

General guidance — it doesn't replace the specific advice your specialist gives you.

Results & realistic expectations

A good result is the cancer responding to treatment, but radiotherapy works gradually and the response is judged at planned follow-up over weeks to months, not on the day. The aim — to cure the cancer or to control it and protect quality of life — depends on your diagnosis, and your oncologist should be clear about which applies.

Proton therapy cannot guarantee a cure or that a cancer will never come back. Its main potential advantage is reducing the dose to healthy tissue in suitable cases, not curing cancers that x-ray radiotherapy could not. For most cancers, outcomes are expected to be similar to good standard radiotherapy.

How long the result lasts depends on the cancer type, stage and the whole treatment plan, not on the use of protons in particular. In children, the main hoped-for long-term benefit is fewer late effects on growth, development and the risk of a second cancer, which is why long-term follow-up is so important. Recurrence and late effects can both appear years later.

Related tests, treatments or support

Proton therapy may be combined with surgery, chemotherapy or other treatments as part of a plan agreed by a multidisciplinary team. Combining treatments can increase side effects. The decision to use protons rather than x-ray radiotherapy should be based on whether it genuinely benefits your specific situation, not on the technology alone.

Follow-up & long-term care

After treatment you stay under your oncology team's care, with follow-up to assess the cancer's response, manage side effects and watch for late effects. For children and young people, this includes long-term checks on growth and development. You should know who to contact between appointments, and private or overseas care should be coordinated with your NHS team and GP.

• Attending long-term follow-up so recurrence and late effects are picked up early
• For children, keeping up checks on growth, hormones and development
• Reporting new or persistent symptoms promptly
• Keeping your NHS team informed if any treatment was given privately or overseas

Repeat, follow-on and what comes next

• Radiotherapy works gradually, so the response is judged at follow-up rather than immediately.
• Further treatment may be needed if the cancer does not respond or comes back.
• Late side effects, including effects on growth in children, may need their own management years later.
• Choosing protons over x-rays does not, by itself, allow a higher or repeated dose if the cancer returns.

Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.

What good aftercare looks like

• Honest, evidence-based discussion of whether protons truly benefit you, with input from your NHS team.
• A named contact and clear route to advice for side effects during and after the course.
• Skin and site-specific care advice, and dietitian or specialist nurse support where relevant.
• A scheduled follow-up plan, including long-term checks on growth and development for children.
• Coordination between any private or overseas team, your NHS oncology team and your GP.

What affects the cost

Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:

• Whether your cancer meets approved criteria, as this affects whether NHS funding applies
• The clinical oncologist's and team's fees for planning and delivering treatment
• The number of treatment sessions and length of the course
• Travel and accommodation if you need to stay near a centre
• Daily anaesthetic or sedation for young children, if needed
• Planning scans, imaging during treatment and follow-up appointments

• Whether the recommendation is supported by evidence for your specific cancer
• The specialist and facility fees for planning and delivering the full course
• Travel, accommodation and length-of-stay costs
• Anaesthetic or sedation costs for a child, if relevant
• Follow-up appointments, scans and who provides them
• What happens, and what it costs, if treatment needs to change or a complication occurs

On the NHS? Proton beam therapy is NHS-funded only for specific approved indications (such as certain childhood cancers and some tumours near critical structures); for most cancers it is not routinely funded because it is not proven to be better than standard radiotherapy.

You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.

Consent traps and marketing red flags

These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.

Choosing a specialist safely

• Check the specialist is on the GMC Specialist Register for this area.
• Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
• You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
• Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
• You're entitled to your total cost in writing — including any follow-up — before you decide.

How Vuemedics verifies every consultant →

Take this to your consultation. A good specialist will welcome every one of these.

• Is there good evidence that proton therapy is better than standard radiotherapy for my specific cancer?
• Do I meet the approved NHS criteria for proton therapy, and if not, why is it being recommended?
• What would standard x-ray radiotherapy involve for me, and how would the side effects compare?
• Is the aim of treatment to cure the cancer or to control it and protect quality of life?
• If a child, will daily anaesthetic be needed, and what long-term follow-up will there be?
• How and when will you check whether the cancer has responded?
• Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
• Will you be the specialist who carries out my treatment, and who looks after me afterwards?
• What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
• What does a realistic result look like — and what can this treatment not achieve?
• What are my options, including waiting, doing nothing for now, or choosing a different approach?
• Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
• What is the total cost in writing, including any follow-ups, and how much time do I have to decide?

Find a verified specialist for proton beam therapy

Every consultant is GMC-checked and independently reviewed. Search by postcode and distance, or switch to a map. Ordered by rating, relevance and recency — never by who pays.

How we made this page

Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →

Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.

Sources & standards: NHS England — Proton beam therapy (commissioning and indications) Macmillan Cancer Support — Proton beam therapy The Christie NHS Foundation Trust — Proton beam therapy FAQs NHS England — Proton beam therapy for head and neck cancer in adults (commissioning review) Royal College of Radiologists — Clinical oncology NHS — Radiotherapy

Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.

Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.