Ashya King: Could The Clatterbridge Cancer Centre offer him proton beam therapy?

Posted 1st September 2014

Statement explaining how The Clatterbridge Cancer Centre offers a different type of proton beam therapy from the kind sometimes used for brain tumours:

The Clatterbridge Cancer Centre is currently the only facility in the UK that offers proton beam therapy, so it’s natural that people may be wondering why we can’t use it to treat Ashya King and other children with brain tumours.

The reason is that there are actually two different types of proton beam therapy: high-energy and low-energy. The Clatterbridge Cancer Centre’s beam is low-energy. It has been specifically designed to treat eye cancers so the beam only travels very short distances of less than three centimetres.

That means that, unfortunately, the beam doesn’t travel far enough to treat a brain cancer. For that, you need a high-energy proton beam. Facilities offering this kind of proton beam therapy are being developed at University College London Hospital and The Christie but there is nowhere in the UK that currently has a high-energy proton beam.

So what’s the difference between proton beam therapy and other radiotherapy which uses x-rays? Cure rates are the same but the benefit of proton beam therapy is said to be a potential reduction in late side-effects.

This is because proton beam radiation falls off very sharply in a ‘cliff’. It reaches its target with intensity but then the radiation drops so doesn’t travel very much further. This makes proton beams suitable for treating vulnerable areas of the body where it’s important to minimise the risk of unwanted side-effects to surrounding tissue. It also means, however, that it is so precisely targeted that a low-energy beam like the one at The Clatterbridge Cancer Centre isn’t suitable for treating a brain tumour.

X-rays tail off more gradually than proton beams, although newer types of radiotherapy can be much more precisely targeted than in the past. This means that people who have radiotherapy for brain tumours are receiving very precise treatment of the highest quality.