Thanks to a £250m investment from the UK government, the first of two NHS Proton Beam Therapy (PBT) centres has opened. After many years of construction, the PBT centre at The Christie Hospital in Manchester is now treating patients. The second planned facility is due to open at University College London Hospital in 2020.

In this blog post, Professor David Sebag-Montefiore, Chair of NCRI’s Proton Beam Therapy Clinical Trials Strategy Group, tells us why research into PBT is so important and how the NCRI is developing a collaborative research strategy around PBT for the UK.

We need high-quality research into PBT

PBT is currently approved for use for treatment in children and for some central nervous system tumours. For treatment of wider patient populations and cancer types, more research is needed to determine if the theoretical rationale for PBT treatment (that it offers benefits over conventional radiotherapy in sparing radiation dose to normal tissue) occurs in practice.

We need to test this new technology to be certain that the most safe and effective (and cost-effective) treatment is being offered.

The precision of conventional radiotherapy has come a long way over the last two decades and there are some examples already of where it would be difficult for PBT to do better – for instance, in the treatment of localised prostate cancer, the long-term side effects we are seeing with conventional radiotherapy are low, so PBT is unlikely to offer additional benefit. This therefore would not be a high priority area to focus research efforts. On the flip-side of this, there are a range of solid tumour sites where there is a clear theoretical benefit for PBT in reducing long-term side effects and the key research questions are: does this translate into meaningful clinical benefit? What is the cost effectiveness of the benefits? Generating clinical evidence is pivotal to determining the required future investment in PBT therapy for patients in the NHS.

Although PBT is new to the UK, the technology has been in use for a while in some other countries, in the USA for example, but high-quality evidence to support its use is unfortunately lacking. NCRI’s CTRad recently published a review of practice changing radiotherapy clinical trials across five tumour sites that have been performed worldwide in radiotherapy over the last 20 years and found 44 conventional radiotherapy trials involving 50,000 patients. This is compared to only three published phase III clinical trials of PBT.

There are still uncertainties around the use of PBT that research needs to answer and we have a way to go before we can use PBT with the same confidence and knowledge base that we have amassed for conventional radiotherapy.

We need to approach PBT research in a coordinated and collaborative way

Clinical trials are often complex, multi-centre projects carried out across disparate geographical locations and involving large numbers of patients. With PBT in the UK, there are added complexities for research – the patient pathway will change for patients who will receive PBT at one of the two PBT centres whereas the standard of care treatment will be delivered locally; we need innovative clinical trial methodology and there is a limit on the research capacity at the PBT centres. So a collaborative approach is especially important.

Through the NCRI’s PBT Clinical Trials Strategy Group, in collaboration with the Cancer Research UK Advanced Radiotherapy Technologies Network (ART-NET) we are connecting the diverse research community and providing essential guidance. We recently published an eight-point framework for the development and delivery of high quality clinical trials in PBT and will be working with both the UK and international research communities to implement this. We we must work with some speed in order to exploit the opportunities that this new and promising technology provides.

We’re making progress already

At an NCRI CTRad workshop in 2018, we reviewed 10 clinical trials proposals involving PBT and provided investigators with expert feedback to strengthen their proposals. At least three of these have progressed further, and we are now supporting the development of these proposals to move them to the next stage; we will also be assisting with the progress of the other proposals.

Furthermore, we are delighted to learn that a PBT study, TORPEdO, that was first presented to one of CTRad’s Proposals Guidance meetings back in 2016 has recently been funded and is now entering the trial set up stage.

About NCRI’s PBT strategy group

  • In August 2017 NCRI set up the PBT Clinical Trials Strategy Group in order to be prepared to seize the research opportunities that would be opened up with the UK’s new NHS PBT centres.
  • The aim of the group is to promote and assist development of high quality clinical studies that will allow us to demonstrate the benefit of PBT to patients.
  • The group has 12 members, including representatives from the two NHS PBT centres and a patient representative.