Proton Beam Therapy
According to Cancer Research UK, around 40% of people who survive cancer do so because of radiotherapy.
A new form of this treatment – proton beam therapy, hit the headlines recently when the parents of a five-year-old boy with brain cancer removed him from hospital without the doctors’ permission so they could get him this treatment. After an international manhunt and a High Court battle the NHS ended up paying for the treatment in the Czech Republic.
The happy outcome is that his parents announced in March that he is now clear of cancer after 30 proton beam sessions.
They felt the need to leave the country as the UK does not currently have suitable proton therapy facilities, although two new centres have been promised by the government by 2018.
So what is Proton Beam Therapy?
The basis of all radiotherapy treatments is bombarding the tumour with high frequency waves which cause breaks in the DNA molecule of cancer cells which prevents them replicating resulting in the tumour dying off.
Conventional radiotherapy uses X-rays which are part of the electromagnetic spectrum. This spectrum ranges from slow frequency radio waves, through microwaves, infrared, ultraviolet and X-rays to the very high frequency gamma rays – all forms of ‘radiation’. The particles involved are photons or light particles.
Proton therapy, as the name implies, uses beams of high energy protons which are essentially hydrogen atoms stripped of their electrons producing positively charged particles.
The key difference between the two types of particle beams in radiotherapy is that protons can be ‘programmed’ to stop and release about 80% of their energy at the specific tumour site due to an effect called the ‘Bragg Peak’. This enables higher doses more safely. Photons, as light beams, keep on going releasing their energy all along their path. This can cause damage to surrounding healthy tissue and cause side-effects.
Is proton beam therapy more effective than conventional radiotherapy?
The main challenge to answering this question is the lack of evidence from research on the benefits of the treatment. Without facilities in the UK and the fact that it is used to treat rare forms of cancer, it has been hard to run clinical trials.
Currently proton beam therapy is offered to specific target groups:
- Children with several specific types of cancer
- Some adults with rare cancers, particularly where they are near the brain, base of the skull or spine
The recommendation is that it is most useful where the tumours are hard to reach or where surrounding tissue is hypersensitive which includes growing children.
Authorities feel that proton therapy is unlikely to cure more people than current conventional radiotherapy, but that more research and clinical trials are needed.
Some of the benefits to patients are pointed out by Dr Adrian Crellin, NHS England’s clinical lead on proton beam therapy and a radiotherapy expert. Dr Crellin explains that the new treatment uses a lower dose of radiation than was the case with its predecessor with less being given to the tissues surrounding the area to be treated. This reduces the side effects but does not necessarily improve the chances of a cure.
What Crellin also stresses is that for the majority of those being treated at the moment there is a lack of clinical evidence to support any claim that proton beam therapy is more effective as a cure for cancer or that it improves the patient’s survival chances.
The UK already has a proton beam therapy centre in the Wirral – however it’s of the ‘low energy’ variety and is only suitable for treating some rare forms of eye cancer.
For other types of cancer, the NHS sends patients abroad for more high energy treatment –having sent more than 370 patients (mostly children) to the US or Switzerland since 2009. But the government have now taken the decision to build two new proton beam centres at the total cost of £250 million in 2018.
These will be based at the Christie Hospital in Manchester and UCL in London as two of the most prestigious cancer research hospitals in the country. A new research focused centre is also going to be opened at in institute at Oxford University. Having these facilities in the UK will make the research and clinical trials needed for future development of the treatment much easier.
It is anticipated that the new facilities will treat about 1,500 patients per year, roughly 1% of patients who receive conventional radiotherapy. At a cost of £250 million, this appears to be a high cost for a few patients. The cost of sourcing proton beam therapy from outside the UK can vary depending on how complex the treatment is. The Christie Hospital anticipate that the NHS service will cost less than £40,000 when it becomes available whereas the cost of outsourcing abroad can exceed £75,000.
The cost is mainly due to the sheer scale of the particle accelerator needed to produce the high energy proton beams which is the size of a jumbo jet. Whilst the patient only sees a donut ring and bed, in the background is this very large and state-of-the-art equipment which doesn’t come cheap.
Could more patients benefit?
This is something that the clinical trials will find out through testing different groups of patients. It may also be that there are groups of patients that shouldn’t be treated with proton beam therapy because conventional radiotherapy may be as effective or even more effective for their type of cancer.
Whatever the outcomes of trials, proton therapy won’t be replacing conventional radiotherapy.
Private health companies have also announced they will be providing proton beam therapy from as early as 2016 and some companies claim that they will make the facilities available to the NHS.
New facilities have been promised in London, Cardiff and Newcastle, costing nearly £100 million with others promised in London’s Harley Street and Moorgate in 2017.
This has been met with some concern that it could end up creating the perception of a two-tier health system – particularly when people don’t fully understand that proton therapy is not a ‘silver bullet’ and that conventional radiotherapy can be just as (if not more) effective for all but the rarest cancers. There are also concerns about these centres operating at the same high standards as the NHS and also being able to integrate into patients’ overall care.