Targeting Resistant Prostate Cancer with Precision Radiotherapy

For many men with advanced prostate cancer, hormone therapy is the standard treatment. It can often slow the growth of the cancer for years, even when the cancer has spread to other parts of the body. For some men, a small number of areas where the cancer has spread stop responding and start growing again. When this happens, men can be offered chemotherapy. While chemotherapy can be effective at further delaying the growth and spread of the cancer, it often comes with side effects that affect everyday life and wellbeing.

Thanks to your support, we funded the TRAP clinical trial, led by Dr Alison Tree at The Royal Marsden. The trial looked at men who were still on hormone therapy and had one or two areas where the cancer had started to grow again. These men received a precise kind of radiotherapy called stereotactic body radiotherapy (SBRT).

SBRT works a bit like shining several spotlights on a small, growing area of cancer. Each light by itself isn’t very strong, but together when they focus on the same spot, they combine to deliver a much stronger effect. In the same way, SBRT works by sending several low-dose beams of radiation from multiple angles focussing on the small areas of cancer, while protecting the healthy tissue around them.  

The results from the trial were astounding. SBRT helped men whose prostate cancer had spread to two or fewer places keep their cancer under control for an average of six months, with 40% of men in the trial still seeing no cancer growth after a whole year. While SBRT can still cause some side effects, they are generally fewer than those from chemotherapy. This treatment also delayed the need for chemotherapy by nearly two and a half years, sparing many of the men from the side effects of chemotherapy during this time. For these men, SBRT was a kinder treatment option, helping men live longer with a better quality of life. 

From research idea to access for all

Idea

Dr Tree and her team wanted to find out if a precise type of radiotherapy could help men whose prostate cancer had spread to a few places and had stopped responding to hormone therapy. This question was explored in the TRAP clinical trial.

Lab research

The team at The Royal Marsden worked on a way to deliver several low-dose beams of radiation directly to one or two sites where the cancer has become resistant to hormone therapy, while giving much lower doses to the surrounding tissue. They wanted to see if SBRT could slow the growth of cancer, delay chemotherapy, and help men maintain their quality of life.

Clinical trial

The TRAP trial showed that this group of men benefitted from the addition of SBRT to their hormone therapy. The treatment slowed the growth of their cancer, delayed the need for chemotherapy, and caused fewer side effects - helping men have a better quality of life.

Approved for use

We’re now funding STAR-TRAP, led by Dr Julia Murray and Professor Emma Hall at The Institute of Cancer Research, alongside Dr Alison Tree. This larger study applies the TRAP approach to an earlier stage of the disease to see if SBRT can help men whose prostate cancer has spread but is still responding to hormone therapy, helping them benefit from treatment for longer. the disease to see if SBRT can help men whose prostate cancer has spread but is still responding to hormone therapy, helping them benefit from treatment for longer.

Access for all

While SBRT is already available at specialist NHS centres, it’s not yet widely accessible and its use is mainly focused towards treating early-stage prostate cancer.

Thanks to your support, the STAR-TRAP trial is now underway, with researchers working to gather evidence on whether SBRT could be an effective treatment option for more men. If the trial proves successful, SBRT could then become available to help many more men live longer with fewer side effects and a better quality of life.