Frequently asked questions

Proton beam therapy is an advanced form of radiotherapy that uses protons (positively charged particles) to target and destroy cancer cells. Unlike traditional X-ray (photon) radiotherapy, protons can be precisely controlled to release most of their energy directly into the tumour, minimising damage to surrounding healthy tissue. This allows for higher, more effective doses with generally fewer side effects, making it particularly beneficial for treating tumours near critical organs and in children.

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Protons (positively charged particles) are accelerated to high energies and directed into the body. They deposit their maximum energy at a specific depth, known as the Bragg peak, directly within the tumour. Beyond this point, the radiation dose drops sharply, sparing healthy tissues behind the tumour. This targeted approach reduces exposure to surrounding organs and tissues, potentially lowering the risk of side effects and secondary cancers.

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Proton beam therapy delivers radiation with incredible precision, targeting tumours while reducing damage to nearby healthy tissue. This makes it especially beneficial for treating cancers near vital organs, in children, or where preserving normal bodily functions is critical. Because protons release most of their energy directly into the tumour and then stop, patients often experience fewer side effects compared to traditional radiotherapy. It can also lower the risk of long-term complications and secondary cancers, helping to improve both treatment outcomes and quality of life during and after therapy.

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When protons enter cancer cells, they cause ionisation, damaging the cells’ DNA and disrupting their ability to divide and grow. This damage is intended to kill cancer cells over time.

At Proton International London, we use proton beam therapy to treat a wide range of cancers where precision is especially important. These include: brain tumours, spinal tumours/sarcoma, head and neck cancers, prostate cancer, breast cancer, lung cancer, and several types of cancer in children. 

As research progresses and our clinical partnerships grow, we’re committed to expanding the list of conditions we can treat.

Most patients have treatment five times a week, for around four to six weeks. Each treatment session lasts around an hour, after which you are free to leave the hospital. During each session, you’ll lie on a treatment bed while our radiographers carefully position your body for scanning. The gantry (the rotating part of the machine) directs the proton beam to the tumour from different angles. Unlike an MRI scan, the gantry does not enclose you, so you shouldn’t feel claustrophobic. You won’t feel anything during treatment, and your radiographers will monitor you closely from a nearby control room.

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Proton therapy is well-tolerated by most people, but there are possible side effects, as with all forms of radiation treatment. 

Side effects of proton beam therapy can develop gradually during treatment and may include:

• Skin reactions: Sore, red skin in the treated area, a bit like sunburn.
• Hair loss: In the treatment area only.
• Tiredness or low energy.
• Sore/dry mouth and throat, and difficulty swallowing: This is common when the head and neck area is being treated.
• Headaches: These are more common if the head is being treated.
• Nausea and diarrhoea: Can occur when the lower abdomen or pelvic area is treated. 
• Emotional changes: Feeling low or emotionally drained is understandable, and you shouldn’t hesitate to ask for support if you need it.

Because proton therapy spares more healthy tissue than traditional radiation, patients often experience fewer and less severe side effects. Your care team will discuss any potential side effects relevant to your specific treatment plan.

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Yes, proton therapy is often part of a comprehensive cancer treatment plan. It can be used in conjunction with surgery, chemotherapy, or other forms of radiation therapy.

Your team at Proton International London will create a bespoke treatment plan and liaise with your wider medical team to determine the most effective combination of therapies for your circumstances.

Since the first hospital-based proton therapy centre opened in 1990, over 60,000 patients worldwide have received this treatment. In the UK, proton therapy has been available to NHS patients since 2008. There are currently only two NHS proton beam therapy centres in the UK, The Christie in Manchester and University College Hospital in London as well as one private provider: Proton International London. The two centres treat approximately 650 patients every year.

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Numerous studies have demonstrated the benefits of proton therapy, particularly in reducing long-term side effects and the risk of secondary cancers. Research suggests that proton therapy is effective in treating various types of tumours while preserving healthy tissue. As more centres adopt this technology, ongoing studies continue to support its effectiveness and safety.

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To find out if proton beam therapy is suitable for you, please fill out our referral enquiry form. You must attach a clinical letter from your doctor, including details of your diagnoses, current treatment plan and recent scans. Our team will review your case promptly and get back to you with their recommendations. 

Once we have received your medical information, your case will be carefully reviewed by one of our consultant clinical oncologists.. They will assess your suitability and aim to update you with the next steps within a few working days.

If proton beam therapy appears to be appropriate, you will be invited to meet with the consultant, either face to face at our London clinic or virtually. Following this consultation, your case will be discussed in detail by your dedicated multidisciplinary team. If they agree that proton beam therapy is the right approach, your case is then presented at a final Technical Advisory Panel (TAP) meeting.

Once approved, you will move on to the treatment planning stage. From your initial enquiry to the start of treatment typically takes around three to four weeks. If your case is urgent, this process will be expedited.

You’re welcome to book a consultation with one of our consultants at our London clinic once we’ve confirmed we have the key medical information we need. For safety and privacy reasons, guided tours of treatment rooms are limited during operating hours; however, we can arrange a visit to public areas at University College Hospital (UCH) and talk you through what to expect in the treatment suite. If you prefer, we can also provide a virtual walkthrough of the patient journey.

Yes. From your first enquiry, you’ll have access to a dedicated patient services coordinator who will guide you step-by-step—booking scans, arranging appointments, and answering practical questions. Clinically, your consultant clinical oncologist leads your care, supported by specialist radiographers, radiotherapy nurses, dosimetrists and physicists. For children, our team also includes play therapists. If you’re travelling from outside London or overseas, our concierge team can help with travel, accommodation and interpreters.

Your personalised quote will be explained in full before you proceed. Each package includes:

• An initial consultation with a Consultant
• MRI & CT treatment planning (including immobilisation devices where required)
• Weekly reviews by the clinical team whilst on treatment
• On-treatment imaging and quality assurance
• Daily proton beam therapy delivery for the prescribed number of sessions (Monday – Friday)
• Discharge summary and one post-treatment follow-up consultation

Items that are often billed separately (as needed) include 

• diagnostic scans performed outside UCH
• non-proton treatments (e.g., chemotherapy)
• inpatient admission if required (if you are a UK resident, this will be covered by the NHS; for non-UK residents, this will be charged at a daily rate). 

We’ll go through your plan line-by-line so you know exactly what’s included.