Revolutionising radiotherapy: how we’re innovating a century old cancer treatment

Radiotherapy has been used to treat cancer for over a century, with the first recorded treatment in 1886, just seven months after Wilhelm Conrad Röntgen discovered x-rays. Thanks to the dedication of scientists and clinicians, many of them supported by Cancer Research UK or its founding organisations, radiotherapy became more accurate and powerful over the following decades, developing into the indispensable treatment we rely on today.

Radiotherapy is now the cornerstone of cancer treatment, benefitting millions of people around the world each year. Maybe due to this prevalence, it is often thought of as a static treatment – as old fashioned, compared to the newer, more ‘exciting’ treatments such as immunotherapy.

In reality, the field of radiotherapy is rapidly evolving and these advances are helping us to treat cancers more effectively and with fewer side effects.

The potential of FLASH

FLASH is ultra-high intensity radiotherapy, where radiation is delivered around one thousand times faster than in conventional radiotherapy. This increase in intensity damages the DNA in cancer cells but spares normal cells. The effect is striking.

Studies show that the damage to normal, healthy cells is up to 50% lower with FLASH, compared to conventional radiotherapy. This reduces side effects, but it allows clinicians to make radiotherapy more potent against cancer – increasing the radiation dose to levels that would result in too many harmful side effects with conventional radiotherapy.

While still currently in an experimental phase, researchers think the potential for this approach is huge. As Dr Petersson says, “I believe eventually all patients will receive FLASH radiotherapy. We have a long way to go, but the potential to revolutionise how we deliver radiotherapy to patients is there.”

Developing new techniques such as FLASH is only possible thanks to the breakthroughs made during discovery research. In many cases this discovery research continues alongside more clinical trials, allowing techniques and treatments to be improved as understanding grows.

This is the case in FLASH. Scientists have shown what FLASH can do and how this could revolutionise radiotherapy, but they still don’t fully understand why it happens. But rather than just accepting this fact, Dr Petersson and his team are trying and solve this mystery. “We’ve demonstrated the FLASH effect, but we still don’t completely understand it. Our focus now is trying to understand biologically what’s going on. If we can understand it, we can optimise it, and that could make FLASH even more powerful”.

We established RadNet in 2019 in response to a nationwide study that found that a lack of integrated research and infrastructure was hampering progress in radiotherapy. To address this, we committed £56m to establish a network of centres of excellence and state of the art facilities. Bringing together scientists from every part of cancer research – from discovery and translational research to clinical trials – to tackle the major challenges in radiotherapy.

As Professor David Sebag-Montefiore, clinical oncologist at the University of Leeds says, “Because radiotherapy is an effective treatment across such a broad range of cancers, it’s clearly a job that can’t be achieved in one centre alone. This network will allow us to focus along the breadth of cancer research and actually make a big impact.” Ultimately, the aim is to establish an effective pipeline that helps translate new scientific discoveries into treatments that will directly benefit patients within the next 10 to 15 years.

The promise of proton beam therapy

One area of focus for RadNet is proton beam therapy (PBT). PBT is a more recent and advanced form of radiotherapy that uses a beam of high energy protons. Unlike the x-rays used in conventional radiotherapy, protons stop at the tumour. This potentially gives a stronger, more targeted treatment, and reduces the damage to surrounding tissues.

PBT may be particularly useful in cases where the cancer is close to vital organs that are especially sensitive to damage, such as parts of the brain, and in children, whose still-developing bodies are more susceptible to the effects of radiation.

Thanks to a £250m investment by the NHS, the UK’s first two PBT units recently opened in London and Manchester. And our scientists have wasted no time in using these new machines to discover how we can best utilise proton beam therapy to improve cancer treatment.

Reducing harmful side effects

One such trial is TORPEdO, led by Dr David Thompson at The Christie Hospital in Manchester. Supported by the Taylor Foundation, this flagship study is looking at whether proton beam therapy can improve the treatment of head and neck cancers. People with these cancers currently have few treatment options and those that do survive often experience long-term side effects.

TORPEdO is testing whether PBT instead of conventional radiotherapy can improve both survival and quality of life. The trial has been enthusiastically received, with the number of study sites increasing from 15 to 19, demonstrating how keen clinicians and patients are for new possibilities to treat these cancers. As Dr Thompson says, “A few of the newly opened trial sites recruited patients immediately after opening, which is testament to how meaningful trials like this are for patients and how much hope it gives them”.

Alongside the TORPEdO trial, its sub-studies are gathering information that could be used to assess how someone will respond to treatment. Such as whether the effect of proton radiotherapy on the healthy tissues surrounding a tumour can be predicted by MRI images or whether it’s possible to see how well a person is responding to a treatment using a simple blood test.

PBT has also shown promise for other cancer types, like breast cancer. Conventional radiotherapy for breast cancer carries a very small risk of heart damage because breast cancers are near the heart. In most people this risk is very low, less than 1%, but for a few, pre-existing health conditions mean they’re at greater risk of experiencing this potentially fatal side effect.

Led by Professor Charlotte Coles at the University of Cambridge, PARABLE is investigating if proton beam therapy can more safely treat people most at risk of heart damage. “Most patients treated with radiotherapy have decades of healthy life ahead of them, but we need to do everything we can to avoid possible future heart problems related to treatment. Standard breast radiotherapy is really effective for most people with very few side effects, but there is a small group of patients for whom proton beam therapy may be a better option.”

The PARABLE trial is a great example of how scientific advances are making it easier to personalise cancer care, offering people with cancer an individualised treatment plan that gives them the highest chance of both long-term survival and quality of life.

These projects are just the tip of the iceberg. With support from networks such RadNet, scientists and clinicians across the UK are working to improve radiotherapy techniques – from the development of new technologies through to better understanding how we can use radiotherapy during a person’s cancer treatment.

Radiotherapy will continue to be a cornerstone of cancer treatment, both in the UK and around the world. But our vision is a future where people can lead longer, better lives free from debilitating side effects. We will get there – and research is the key.

With thanks to the Taylor Family Foundation for their generous support of our work into proton beam therapy. 

Written by Dr Hattie Brooks, Science Engagement Manager at Cancer Research UK.