RecruitingInterventional

Using targeted radiotherapy to postpone the need to change treatment in men diagnosed with metastatic prostate cancer

When prostate cancer spreads to other parts of the body, doctors usually treat it with hormone therapy to keep it under control. Over time, the cancer can start to grow again, meaning patients need to switch to stronger treatments that may cause more side effects. This trial is called STAR-TRAP. It is testing whether adding a focused, high-dose radiotherapy called stereotactic body radiotherapy (SBRT) can help men who have five or fewer active cancer spots. SBRT aims high-energy beams directly at cancer spots while protecting healthy tissue. Half the participants will carry on with their usual medication alone. The other half will also receive targeted radiotherapy to their cancer spots over two weeks. Researchers hope this extra treatment will delay the cancer from progressing and allow men to stay on their current medication for longer.

At a glance

Status

Recruiting

Sponsor

Institute of Cancer Research

Enrolment target

236

Start

19 Dec 2024

Estimated completion

18 Dec 2026

Prostate cancer

What is this study about?

Prostate cancer often responds well at first to hormone treatments, which work by starving cancer cells of the hormones they need to grow. However, over months or years, cancer cells can adapt. When this happens, doctors usually have to move on to different treatments, such as chemotherapy or other medicines, which can bring unwanted side effects and impact daily living.

Doctors have noticed that sometimes cancer only remains active or starts regrowing in a few small places—often five spots or fewer. This trial aims to find out if using a highly targeted type of radiation, called stereotactic body radiotherapy (SBRT), can wipe out these few remaining or growing spots. By clearing these areas, doctors hope to keep the rest of the cancer quiet and delay the need for new drugs.

SBRT is already used safely for several types of cancer across the NHS. It delivers pinpoint beams of radiation directly to tumours with great accuracy, meaning healthy surrounding organs receive very little radiation. If this study shows that SBRT works well for advanced prostate cancer, it could change standard NHS practice and give patients more time with their cancer kept under control.

Key takeaways

The STAR-TRAP trial tests if targeted radiotherapy can keep advanced prostate cancer stable for longer.
It is designed for men with five or fewer active cancer spots on scans.
Participants continue their normal hormone therapy, with half also receiving targeted radiotherapy over two weeks.
The goal is to delay the need for stronger, more demanding treatments.
Taking part involves extra hospital visits for scans, radiotherapy sessions, and follow-up checks.

Who may be eligible?

This study is open to men aged 18 and over who have been diagnosed with prostate cancer that has spread to other parts of the body. To take part, you must already be receiving standard hormone therapy (sometimes alongside chemotherapy) and be reasonably active and able to look after yourself in daily life.

You may be suitable if you fit into one of two groups. The first group includes men whose initial treatment has worked very well, leaving five or fewer active cancer spots visible on scans. The second group includes men whose PSA blood test has recently started to rise, but scans show that no more than five cancer spots are growing.

You will not be able to take part if you have previously received radiotherapy very close to the cancer spots that need treatment, as having more radiation to the same area might not be safe. Your hospital care team can check your past scans and treatment history to confirm if you are eligible.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

I am a man aged 18 or older.
I have been diagnosed with prostate cancer that has spread beyond the prostate.
I am currently receiving standard hormone therapy (such as enzalutamide, apalutamide, abiraterone, or darolutamide).
My scans show five or fewer active cancer spots.
I am well enough to carry out daily activities and attend hospital appointments.

Answer every question to see your result.

What does participation involve?

If you take part, a computer will place you by chance into one of two groups. This is called randomisation. One group will continue with their standard hormone medications as normal. The other group will continue their standard medications and also receive targeted radiotherapy (SBRT) to their cancer spots, and sometimes to the prostate as well.

If you are chosen to receive radiotherapy, you will attend hospital for between three and five short treatment sessions over a two-week period. These are outpatient visits, meaning you can go home the same day. Before treatment begins, you will have detailed imaging scans, such as a PET-CT or MRI, so the team can map out exactly where the radiation needs to go.

All participants will have regular check-ups, PSA blood tests, and scans so doctors can monitor how well the cancer is controlled. You will also be asked to fill in questionnaires about your general well-being and any side effects. The study is scheduled to follow participants over several years.

Potential risks and benefits

There is no guarantee that taking part will improve your health, but the radiotherapy might destroy remaining cancer spots and delay the need for more intensive treatments. The knowledge gained will also help doctors care for men with prostate cancer in the future. As with any radiotherapy, there is a risk of side effects, which can include tiredness, temporary soreness, or irritation to nearby organs such as the bowel or bladder. Your care team will explain these risks in detail. Taking part is entirely voluntary, and you are free to leave the trial at any time without your regular NHS care being affected.

Locations (2)

The Royal Marsden Hospital (surrey)
City only
Sutton, England
The Royal Marsden Hospital (london)
Approximate
London, England

Common questions

What is SBRT?

SBRT stands for stereotactic body radiotherapy. It is a modern technique that uses computer guidance to aim high doses of radiation at tumours with pinpoint precision, sparing healthy tissue nearby.

Will I have to stop taking my current cancer medicine?

No. Everyone in the trial continues taking their standard hormone therapy. The study simply tests whether adding radiotherapy gives extra benefit.

Can I choose which treatment group I go into?

No. A computer allocates participants at random to ensure the two groups are fairly balanced. This is the best way to prove whether the radiotherapy really helps.

Does the radiotherapy require a stay in hospital?

No. Radiotherapy sessions are done as an outpatient. Each appointment takes a short time, and you can usually go home straight afterwards.

What happens if my cancer gets worse during the trial?

Your doctors will monitor you closely with scans and blood tests. If your cancer shows signs of growing, your medical team will discuss switching you to other standard NHS treatments right away.

How to find out more

Sandy Cheung

startrap-icrctsu@icr.ac.uk +44 (0)20 3437 6660 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.