What to expect when having proton beam therapy

It’s natural to have questions and concerns before starting any sort of cancer treatment. That’s why we’ve created this clear and comprehensive guide to walk you through the proton beam therapy experience step by step – before, during, and after your treatment.

You may have read about how proton beam therapy works, its benefits, and which cancers it’s most effective at treating. But clinical details aside, we realise that you may have a lot of questions about what the experience is like. Can my family accompany me? How long will it take? Will I need to stay in hospital? These are all valid questions which we will answer in this guide.

Aside from your recovery, our biggest goal is to help you and your loved ones feel informed and reassured throughout the entire journey, from your initial appointment to your treatment sessions and beyond.

Quick guide: what to expect when having proton beam therapy

Your proton therapy treatment experience

Once you have made a successful referral request and our team has determined that proton beam therapy is a suitable treatment for you, you will begin your treatment journey.

Here is what to expect at each stage.

1. Before your treatment

You will be invited to our London clinic for an initial consultation with one of our specialist oncologistsand members of your care team. The radiation oncologist will discuss your diagnosis with you and talk you through the proposed treatment. They will ensure you understand what the treatment entails, what the potential side effects are and answer all of your questions. We encourage you to bring along a friend or family member for all consultations.

Following your consultation, you may need to undergo an MRI and/or CT scan to provide additional information about your tumour. These will be carried out at UCH (where Proton International London is based) or at another nearby private hospital.

In this phase, we will also discuss the costs of your proton beam therapy and explain your payment options.

2. Preparation for treatment

Careful and precise treatment planning is crucial for proton beam therapy. Our highly experienced team of radiographers, dosimetrists, radiotherapy physicists, and radiation oncologists will create a bespoke treatment plan based on your general health, consultations, past treatments, and scan results.

You will need to attend the hospital for the following appointments:

• Device fitting: It’s essential that you remain as still as possible during proton beam therapy treatment. This allows us to target the cancer cells precisely and minimise radiation exposure to healthy tissues surrounding the tumour. For example, for head and neck cancers, you may require a custom-made mould (also known as an ‘immobilisation device’ or ‘shell’) to keep the head still during treatment. The lightweight, bespoke mesh will fit snugly to your face, which may feel a little unusual at first, but you will be able to see, speak, and breathe normally while wearing it. The use of a shell is dependent on your tumour type and location and you will be advised if required in your initial consultation.
• Treatment set-up: You will be asked to attend a treatment set-up and simulation, which involves gently positioning your body in the correct position on the treatment table. Our team may use small skin marks (either temporary or permanent) to help us place you in the exact same position for each session.
• Scanning: You may need to undergo further CT and/or MRI scans to examine the size, shape, and location of the tumour, as well as surrounding healthy tissues and organs.

Before your first treatment, our expert team will use advanced planning software to work out how to deliver the proton beams with pinpoint accuracy, adjusting the angle, depth, and intensity to treat the tumour effectively while sparing as much healthy tissue as possible. They will also perform rigorous daily quality assurance checks before and throughout your treatment to ensure the treatment remains safe and effective.

Your team

Many different healthcare specialists are involved in the planning and delivery of treatment at Proton International London, including:

• Radiation oncologists – Doctors who lead your treatment.
• Dosimetrists – Specialists who calculate the exact dose of radiation needed.
• Radiotherapy physicists – Experts who ensure the proton radiation is delivered safely and accurately.
• Radiation therapists/therapy radiographers – The professionals who guide you through each session and operate the proton beam machine.
• Radiotherapy nurses – Specialist cancer nurses who offer medical support, advice, and reassurance during your treatment.
• Specialist radiographers – Radiographers who specialise in specific aspects of care, such as imaging or paediatrics.
• Play therapists (for children) – Professionals who use play to help children understand treatment, reduce anxiety, and feel more comfortable in the hospital environment.

3. During your treatment

The good news is that you will receive proton beam therapy as an outpatient, meaning that you can leave straight after the session. Just like traditional radiation therapy, you will be perfectly safe to be around others, including children. In most cases, you can drive after radiotherapy treatment, but this is not advised if you are suffering from fatigue or other side effects.

How often: Most patients have proton beam therapy every day from Monday to Friday, for around four to six weeks. If there is a public holiday or you are ill, sessions are sometimes moved to the weekend.

How long: Treatment appointments last around 60 minutes. The actual proton beam treatment takes approximately 20–40 minutes, and the additional time is used for positioning you correctly and conducting imaging checks.

We aim to deliver proton beam therapy without interruptions wherever possible. If a break is needed due to illness or technical issues, your clinical team will carefully review your situation to determine the best course of action. In rare cases, a short course of photon radiotherapy may be recommended as a backup – this will be explained during your consultation, if relevant to you.

In addition to treatment sessions, you will have regular check-ups with your radiation oncologist and another member of the team (typically, a radiotherapy nurse, specialist radiographer, or fellow proton beam therapy doctor) to review your progress and discuss any side effects.

What happens in a proton therapy treatment session

• The area of your body being treated needs to be exposed during proton beam therapy, so you may be asked to remove some clothing or change into a hospital gown. But rest assured that we will do our best to respect your privacy, dignity, and personal or cultural preferences. If you wish to be treated by someone of a particular gender, please let us know in advance, and we will do everything possible to accommodate you.
• Our radiographers will carefully place you on the treatment table in the position determined during the simulation planning stage. If necessary, they will ensure your immobilisation shell/mask is fitted correctly.
• The radiographers will position the gantry (the large rotating part of the proton beam therapy machine) to align the beam with the treatment set-up marks on your skin. Unlike the confined space of an MRI machine, the gantry is open, so you should not feel claustrophobic.
• You will be asked to stay very still as the treatment is administered.*
• An X-ray or a brief CT scan will be taken in the treatment room to confirm that your position is accurate.
• The therapy radiographers will leave the room to safely operate the machine from a shielded control area. But there is no cause for alarm. A video camera allows them to see, hear and talk to you during treatment, so you will not be alone.
• Once treatment begins, the gantry will project a fine beam at the area being treated. It moves around you to target the tumour from multiple angles, ensuring precise and effective treatment. You won’t be able to feel the beam at any point during the treatment – it is completely painless.
• You may hear clicking noises several times during treatment, as the proton beam stops and starts to reposition itself.

*We sometimes recommend that younger children undergo a general anaesthetic to ensure they remain still during treatment. As a parent or guardian, you can stay with them until they fall asleep and be with them as they wake.

4. After your treatment

At Proton International London, your care doesn’t stop when the course of treatment ends. Our consultant radiation oncologists and patient services team will stay in contact to monitor your recovery, help you manage any side effects, and keep your wider medical team informed.

We’re here to support your physical health, but also understand the emotional toll treatment can take on you, your family, carers or children. We can refer you to trusted specialists, including psychologists, to help you adjust and cope.

Possible side effects of proton beam therapy

Possible side effects of proton beam therapy
One of the main advantages of proton treatment is that it can treat cancer with greater precision than other radiation therapies. It accurately targets tumours, reducing the radiation dose to surrounding healthy cells. As a result, the risk of side effects and developing secondary cancer is significantly reduced. This is why proton beam therapy is used to treat younger patients and types of cancer which occur near sensitive organs, such as prostate cancer and lung cancer – see which cancers we treat here.

That said, side effects can still occur during proton beam therapy, similar to those experienced during conventional photon radiation therapy. Your care team will explain what you might expect in your individual case, closely monitor your symptoms, and provide support throughout.

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

• Skin reactions: Some patients experience sore, red skin in the area the proton beam hits, which can look and feel like sunburn. Skin reactions can be more intense with proton beam therapy than with other radiation treatments, as more energy is delivered to the entry point.
• Hair loss: In the treatment area only.
• Tiredness or low energy: This may build as the treatment progresses, and many patients report becoming more tired around the midway point.
• Sore/dry mouth and throat: This is common when the head and neck area is being treated, which can make swallowing more difficult.
• 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. Staying hydrated, making dietary adjustments, and taking medication can help.
• Emotional changes: Feeling low, anxious, or emotionally drained is certainly not uncommon, and you should feel comfortable asking for support if you need it.

Side effects develop during treatment, peaking in the final week. They should continue for no longer than a week after treatment has finished, and stop around four to six weeks after your last session. Your therapy radiographers and clinical review team will monitor you very closely throughout treatment to see how your body is responding and provide support.