Radiotherapy works to treat cancer because X-rays damage cancer cells, meaning they can no longer multiply and will die. But the beams don’t discriminate between cancerous and normal tissue, and can cause serious side effects by destroying healthy cells in their path.
Over the past 50 years, advances in technology have meant that doctors can shape radiotherapy ever more precisely to match the shape and size of a patient’s tumour. Some of the latest machines can even track how tumours move as a person breathes, to make sure they’re hitting as little healthy tissue as possible while zapping the cancer.
But no matter how advanced the techniques get, one problem with X-ray radiotherapy remains – once the beams have entered a person’s body, they keep going. Although the radiation beams are focused on a tumour, so the dose to the surrounding tissues is minimised, there will inevitably be some potential damage, leading to short or long-term side effects.
While this is obviously not ideal for cancer patients at any age, it can be particularly harmful for children (especially those being treated for brain tumours) as their bodies are still developing and they’re more susceptible to the effects of radiation. They’re also more at risk of developing a second cancer later in life, caused by their early exposure to radiation. So there’s always the need to strike a balance between delivering a big enough dose of radiotherapy to kill all the cancer cells, while inflicting as little damage as possible on the healthy tissue around them.
One way to avoid these problems is to zap tumours with a beam of protons , rather than X-rays. Protons are positively-charged tiny particles that are found in the centre ( nucleus ) of every atom in the universe, and they can be generated and focused into beams in a controlled way using large particle accelerators.
Like regular radiotherapy treatment, proton beam therapy damages cancer cells in the same way, so that they die. But unlike X-ray beams, proton beams stop once they hit their target, rather than carrying on through the body (due to a quirk of physics known as the Bragg peak , if you’re interested).
This cuts the chances of damaging the surrounding tissues, reducing side effects – something that’s especially important if you’re dealing with a small child’s developing brain and body. However, it’s important to remember that the treatment isn’t a “magic bullet”, and it won’t be suitable for everyone. And although it looks like proton beam therapy has fewer side effects than conventional radiotherapy, it still carries some risks and uncertainties.
At the moment, there are two options for NHS patients whose doctors think they are suitable for proton beam therapy.
Patients with rare types of eye cancer can go to the proton therapy centre at the Clatterbridge Centre for Oncology in Merseyside. The hospital was the first in the world to have its own cyclotron (a machine that generates proton beams), built in 1989 and still going strong.
Thousands of people have been treated there over the years, and more than eight in 10 of them have kept their sight after treatment. But the proton beams produced in Clatterbridge are relatively low energy, and can only travel around three centimetres into the body. So they can’t be used to treat other types of tumour.
The other alternative – mostly for adults and children with brain tumours – is to head abroad for proton therapy. It’s important to point out that at the moment, there’s a lack of good evidence to show that most people who get proton therapy abroad will do better than those who get conventional treatment here in the UK.
Those who do travel for treatment go to the US. There are two US centres used by NHS patients – the University of Florida Proton Therapy Institute in Jacksonville and the ProCure Proton Therapy Centre in Oklahoma City.
Last year Lucy Thomas, aged seven, was diagnosed with a rare type of muscle cancer called rhabdomyosarcoma in her nose and mouth. After surgery and chemotherapy, she and her whole family travelled to Oklahoma where Lucy had 28 doses of proton beam therapy.
Her mum Caroline says:
As a result of her treatment, Lucy wants to be a proton beam therapist in the UK and help other children. And although she’s still having regular checkups, things are looking good and she’s enjoying life back at school.
NHS patients like Lucy first started being treated with proton beam therapy overseas in 2008 , at a cost of around £90,000 per person. But there can also be extra costs, such as any additional medical treatment, living expenses and accommodation for extra family members or carers, so families often turn to charities or their own fundraising to cover the expenses.
Given the key need to treat some patients, particularly children, within a set time, the extra complexity of transferring care abroad raises new risks and could even affect their outcome. So getting the balance right is complicated, and the NHS system takes all of this into account.
There are also issues with transferring medical data across borders (especially images of scans), as well as arranging visas and travel insurance for patients. But despite these hurdles, since the programme started in 2008 a total of 370 patients have been approved for proton therapy abroad, of whom two thirds are children.
So far it’s difficult to tell, as the numbers of patients affected by any one type of cancer are very small, particularly for very rare childhood tumours. This makes it hard to compare survival with people who’ve been treated in other ways.
The data on adults from the UK treated abroad seem to show that they are doing well after proton therapy, but the patients who get the treatment have been selected for it specifically because their doctors think they have a good chance of doing well from it.
For children, the outcomes seem to be comparable to the standard treatment they would have received in the UK. However, it’s too early to say whether the kids who’ve had proton therapy suffer fewer long term side effects than those who had conventional radiotherapy, which is where the really big benefits could lie (assuming that both treatments are equally effective).
In August 2013, the UK government confirmed that £250 million would be made available to build two UK proton therapy centres – one at the Christie Hospital in Manchester, the other at UCL Hospital in London. They’re due to open in 2018, and there’s also an option on the table to have a third facility in Birmingham at some point in the future.
Both facilities will primarily cover English patients, as England’s NHS ‘pot’ is bearing the brunt of the costs, but it’s anticipated that Scottish, Welsh and Northern Irish patients will also be able to use them.
This is a big sum of money for just two treatment centres that are expected to treat around 1,500 patients per year between them – many more people than are currently sent abroad for proton therapy.By way of comparison, the new conventional radiotherapy centre being built at the Beatson Centre in Glasgow seems a snip at just £25 million. Yet the cancer drugs fund – which provides highly expensive drugs, many of which are aimed at prolonging life rather than cure, to around 28,000 patients – costs £200 million per year.
The high costs are due to the fact that these are huge bits of kit. Although a patient will walk into a relatively small room for their treatment, containing a bed within a doughnut-shaped machine, this is just the ‘tip of the iceberg’. Behind that lies an enormous particle accelerator weighing hundreds of tonnes, responsible for generating high-energy proton beams.
However, at around £40,000 per patient, the costs should ultimately work out as cheaper than sending people abroad and are expected to fall over time. What’s more, having facilities in the UK will cut down some of the extra expenses for families and carers. And it should also enable more people to benefit from the treatment.
Importantly, the new proton beam therapy centres are located in two of the UK’s major hubs for cancer research, which are also key care centres for rare adult cancers, as well as children and young adults with cancer. This should help doctors to answer some of the questions that still remain about the effectiveness of the treatment, how best to use it, and who’s most likely to benefit.
Many people involved in cancer research and treatment have welcomed the commitment to build these new proton therapy facilities, but there are a number of issues and concerns that have been raised about bringing such expensive technology to the UK.
When making decisions about cancer treatment, it’s important that they should be based on the best scientific evidence available. One problem with proton beam therapy is that it’s often used to treat very rare cancers, where it’s difficult to gather enough data to get meaningful results. As a knock-on effect, this means that relatively few studies have been published, making it hard to judge exactly how effective the treatment is.
Complicating the issue is the situation in the US, where there’s been a sharp increase in the number of men with prostate cancer who are being treated with proton beam therapy, with little evidence that it’s any better than conventional treatment . It’s been made clear that prostate cancer patients won’t be treated at the new UK proton therapy centres , as they’ll be focusing their time and energy on childhood and rare adult cancers.
At the same time, conventional radiotherapy is getting better all the time – with techniques like stereotactic, image guided and intensity modulated radiotherapy – and there’s an argument to say that the government should focus on expanding access to these technologies ahead of building proton facilities.
Researchers with long memories also remember the saga of neutron beam therapy back in the 70s and 80s. Like protons, neutrons are tiny subatomic particles rather than waves like X-rays. Large amounts of money were invested in equipment and clinical trials, but the results were disappointing and plans for neutron therapy in the UK were shelved.
So there’s understandable caution on the part of some people when it comes to this kind of technology. However the fundamental difference is that protons have very similar biological effects on cancer and normal cells as X-rays, but still have all the advantages of neutrons in terms of better accuracy and a beam that doesn’t go beyond the cancer.
Here in the UK, we’ve made big strides in treating cancer successfully by bringing together doctors, surgeons and radiotherapists into multidisciplinary teams, providing joined-up care for patients throughout their cancer journey. There’s a risk of breaking up individual patients’ care by sending them a long way from home for treatment. And there’s also the issue of providing treatment across the whole of the UK population. Having just two national centres means that some people will find it easier to get there than others, which could lead to inequalities in treatment.
Finally, at least three private healthcare companies have announced plans to build their own proton therapy centres here in the UK, treating NHS and private patients. But it’s not clear how much the NHS would be charged to use the facilities, how decisions might be made on who gets access to therapy, or what the technical specification for the treatment machines would be. This means that the NHS is unlikely to get into bed with the private sector, at least as far as proton beam therapy is concerned.
Doctors think that around one per cent of patients treated radiotherapy in the UK could be suitable for proton therapy. This would mostly be children with various types of cancer including brain tumours, as well as adults with brain tumours, head and neck cancers, spinal tumours and sarcomas. In addition, people with more common types of cancers in tricky locations of the body that would be difficult to treat with conventional radiotherapy might also benefit.
As the UK’s proton therapy centres come to fruition over the next five years, there’s still a vital need to continue gathering and analysing research data from patients receiving the treatment around the world, so doctors can figure out the most suitable candidates for treatment and the best way to use it.
Overall, we’re very happy to hear that the government is investing in cutting-edge techniques like proton therapy – although, of course, this shouldn’t be at the expense of conventional radiotherapy, which still saves thousands of lives.
With the right investment in technology and people, the UK’s radiotherapy services could be among the best in the world. We will continue to keep pushing the government to make sure this happens and even more lives can be saved.