Proton Beam Therapy (PBT) is a type of radiotherapy treatment that uses beams of 'protons' (energised particles), instead the x-rays ('photons'), used in conventional radiotherapy. The aim of both treatments is to direct the radiation towards the tumour cells and destroy them.
With conventional radiotherapy, the beams of X-rays are carefully planned to deliver most of their energy within the tumour, whilst avoiding as much healthy brain tissue as possible. However, the X-rays do also release some of their energy before they reach the tumour, and continue to release some after they have passed through the tumour and continue on through the brain to exit on the other side of the head. This causes some damage to the normal, healthy cells in the path of the radiotherapy, but normal brain cells are more able to repair themselves than tumour cells. This initial damage to the normal cells, however, can cause side-effects in the short-term. Some of the damage may be unrepairable, leading to long-term effects.
Similarly, in PBT the beams of protons are carefully planned to target most of their energy within the tumour.
However, by altering the beam energy, the beam can be designed so that the protons stop and release most of their energy accurately at a particular depth in the brain i.e. where the tumour is situated.
This means that although some of the energy will be released before they reach the tumour, the main radiation dose can be given to the tumour and very little is released the other side of the tumour. (The beam is usually set up to travel a little way past the tumour to make sure it gets any tumour cells beyond the edge of the tumour that can't be seen.)
This means that fewer healthy cells nearby receive a dose of radiation. This is particularly important in children, whose brains are still developing.
Whether your child can have PBT depends on many factors, including:
If the strict set of criteria for referral are met, your child's oncologist will refer you to one of the approved PBT treatment centres, children are normally treated in the USA.
The referral process has many stages, which can take nearly three months (11 weeks) to complete - from when your child's consultant first suggests this could be appropriate treatment to receiving the first PBT.
At any stage, treatment can be refused on the grounds of PBT not being the best option for your child.
The NHS will cover the cost of PBT at these approved treatment centres. It will also fund economy travel and approved accommodation for the patient, plus one to two carers/parents accompanying them. The NHS will NOT fund any meals or refreshments, nor any upgrades to travel or accommodation.
You will need to sort out your own travel insurance and appropriate visas. (If you are going to the US, your travel insurance will be refunded).
(There are slight variations to the process of NHS funding according to which UK nation you live in.)
If you need help with associated essential costs not covered by the NHS, contact our Support & Info Line about sources of grants and other financial help that may be available. Alternatively, your local neuro-oncology centre may have access to charitable funding.
(There are other (private) centres overseas. However, these can be expensive, may not have sufficiently trained staff and often don't offer other treatments, such as chemotherapy, which may be needed alongside the PBT. This could influence the overall effectiveness of the treatment.)
Two Proton Beam Therapy centres for treating brain tumours are planned in the UK - in Manchester (opening 2018) and London (opening 2020).
The procedure for giving PBT is very similar to conventional radiotherapy.
There will be several planning appointments at the treatment centre before you/your child starts PBT. These include:
You will then usually be able to go straight home.
The treatment generally only lasts one minute, but with the positioning and adjustments, the session is likely to be about 20 minutes.
It is usually given daily (Monday to Friday) for up to 5-7 weeks. This depends on your child's tumour type and grade.
You will need to be away from home for at least 8 – 10 weeks.
It is important to appreciate that Proton Beam Therapy is not suitable for everyone.
It is also important to realise that:
Our FREE Brain Tumour Information Pack has been designed to help you through this difficult time, to guide you through the healthcare system, answer your questions, and reassure you that you're not alone so that you feel confident when discussing treatment and care options with your child's medical team.
If you have further questions, need to clarify any of the information on this page, or want to find out more about research and clinical trials, please contact our team:
0808 800 0004 (free from landlines and mobiles)
Phone lines open Mon-Fri, 09:00-17:00
You can also join our active online community on Facebook - find out more about our groups.