TRAP: targeting hormone resistant metastases with radiotherapy

What you need to know

  • Treatment options for men with advanced prostate cancer are limited. We need to make sure the treatments we do have work for as long as possible.
  • We're funding Dr Alison Tree to carry out the TRAP trial: using a new kind of radiotherapy to kill treatment-resistant tumours, helping men stay on their current treatment for longer.
  • She hopes the project will lead to a larger-scale trial, that will bring the new treatment to men in five years. 

What they want to find out

Dr Tree from the Royal Marsden, London, plans to conduct a clinical trial, TRAP, for men whose cancer has just begun to grow after treatment with abiraterone or enzalutamide. At the moment, disease progression after hormone therapy is taken as a sign that the cancer has become resistant to the treatment. However, Dr Tree thinks that for some men, it may just be some tumours that are resistant and, if she treats those, the rest of the cancer will still respond to abiraterone or enzalutamide.

By the end of this grant, Dr Tree hopes to show that for some men, treating their metastases with targeted radiotherapy can extend the time that their cancer responds to hormone therapy. She also hopes that the MRI scans and liquid biopsies will have given them some insight into the mechanism of hormone resistance and cancer spread, and could be used in the future to predict who will respond best to this new type of treatment.

In the long term, Dr Tree plans to run further, larger scale clinical trials that, if successful, will provide the evidence needed to make SBRT alongside continuing hormone therapy standard of care for the men who will benefit most from it.

How are they doing it 

She will test this idea by recruiting men whose cancer is only growing in one or two sites. They will continue to receive abiraterone or enzalutamide, but the growing tumour will be hit with a precisely targeted form of radiotherapy called Stereotactic Body Radiotherapy (SBRT). This involves hitting the tumour with beams of radiation from different directions, so that while the cancer receives a high dose of radiotherapy, the surrounding tissues experience much lower doses, which reduces side effects.

While the men are at the hospital for their radiotherapy appointments, Dr Tree will also take blood samples from them. They’ll also have a special type of whole body MRI scan before their first treatment and 6 months after radiotherapy.

The MRIs will help them to see if they can predict who SBRT plus continuing hormone therapy is likely to work best for. They will use the blood samples as liquid biopsies; examining the tumour DNA circulating in the blood to see whether it contains any markers that suggest the cancer’s resistance to hormone therapy has changed after SBRT, but also to see if they can find markers to predict which men will benefit most from this type of treatment.

The trial has begun recruiting patients from the Royal Marsden and is continuing to open recruitment sites across the UK, which you can find below. 

I hope that in five years we’re treating these kinds of patients very differently. I hope we’ll be using radiotherapy as standard to pick off drug resistant parts of the cancer, and this will mean we can keep men on hormone therapy for longer. And that means less men will die of prostate cancer in the future.
Dr Alison Tree, Chief Investigator of TRAP

How to get involved with this trial

This trial is still looking for men to take part. You can read the information below to see if you may be suitable to take part in this study, and contact your medical team for full details on whether you can take part.

If you’d like support with deciding whether taking part in a clinical trial is right for you, you can speak to your medical team or contact our Specialist Nurses on 0800 074 8383.

Who can take part

You may be suitable to take part in this study if you have:

  • Metastatic hormone therapy-resistant prostate cancer, treated with Enzalutamide or Abiraterone 
for a minimum of 6 months. 
  • 1-2 metastatic lesions progressing on imaging (CT, bone scan, MRI or other local imaging) or a clinical or imaging diagnosis of progression of a non-irradiated primary site with the remainder of their metastases currently controlled by Abiraterone or Enzalutamide. 

  • No previous radical radiation to the index area (defined as unable to deliver the SBRT doses in this protocol without taking normal tissues beyond tolerance) 

  • Oligoprogressing site in bone, lymph node, prostate or lung (liver, brain, adrenal or other sites are excluded) 
This includes sites that have developed on treatment.

Who can’t take part

You would not be eligible to take part if you have:

  • A clinical need to switch therapy immediately (e.g. no suspicion of rapid clinical progression)
  • Had previous invasive cancer in the past 5 years, with the exception of non-melanoma skin cancer and small renal masses under surveillance (non-invasive malignancies such as non-muscle invasive bladder cancer are not excluded)
  • Contra-indication to radiotherapy (eg inflammatory bowel disease, where relevant)
  • Contra-indication to MRI (eg Cardiac pacemaker, Internal defibrillator, shrapnel injury, claustrophobia)
  • Lesions that are not suitable for SBRT (e.g. size of > 6 cms)

For full inclusion and exclusion criteria speak to your medical team.

Where the trial is taking place

  • Royal Marsden, Sutton 
  • Royal Marsden, Chelsea
  • Newcastle Freeman Hospital
  • Clatterbridge Hospital, Wirral
  • Christie Hospital, Manchester
  • Velindre Cancer Centre, Cardiff

Please note, We try to keep this information as up to date as possible, but there may be times when study details have changed and we haven’t updated our web information. Speak to your medical team, or our Specialist Nurses, for the most up to date information on prostate cancer clinical studies.

Grant information

Reference - RIA16-ST2-006
Researcher - 
Dr Alison Tree
Institution – The Royal Marsden NHS Foundation Trust
Award - £574,415