STAMPEDE2 is a UK‑wide clinical trial for people whose prostate cancer has spread to other parts of the body but is still responding to hormone treatment. Run by University College London, the study welcomes people from all backgrounds and ethnicities. Its aim is to find out whether adding a new type of targeted radiotherapy to standard treatment can slow the cancer down and help people live longer.

Everyone who joins the trial will receive the best current standard care for advanced prostate cancer. This includes ongoing hormone therapy (ADT) and one of the modern hormone‑targeting drugs such as abiraterone, enzalutamide, apalutamide, or darolutamide. Some people may also have chemotherapy (docetaxel) or radiotherapy to the prostate, depending on their individual situation.

After joining the study, a computer will randomly assign each person to one of two groups. This is done completely by chance, like flipping a coin, and means there is a 50/50 chance of being placed in either group.

·One group will continue with standard treatment alone (Control group).

·The other group will receive standard treatment plus targeted radiotherapy called SABR to areas of spread. SABR is designed to treat all visible areas of cancer and is usually delivered in three to five treatment sessions (Experimental Group).

The purpose of comparing these two approaches is to see whether adding SABR can slow the cancer’s growth, keep it under control for longer, and ultimately help people live longer.

Throughout the trial, participants will have regular scans, blood tests, and check‑ups so the clinical team can monitor how the cancer is responding and look out for any side effects. Treatment will be stopped if side effects become too difficult or if a participant chooses to leave the study at any point. People can withdraw whenever they wish, and their clinical team will continue to support them with appropriate care.