Radiotherapy is a very effective treatment for prostate cancer that is still contained within the prostate. Thanks to improvements in technology, we can now give radiotherapy much more precisely. This means higher doses can be delivered safely in fewer treatment sessions. Prostate radiotherapy used to take 37 sessions, and the current standard is 20 sessions.

Recent research has shown that giving radiotherapy in just 5 sessions works just as well as 20 sessions for men with early prostate cancer.

One of the newest machines, called an MR‑Linac, combines an MRI scanner with a radiotherapy machine. This allows doctors to see the prostate clearly before each treatment and adjust the radiotherapy to match the position of the prostate and the surrounding organs on that day. This helps make treatment more accurate.

Even with these advances, some men still experience side effects from radiotherapy. These can affect the bladder, bowel, urethra, or nearby nerves because these organs sit very close to the prostate. To reduce side effects, we would need to reduce the dose of radiotherapy to these healthy tissues — but this is difficult if the whole prostate receives the same high dose.

This study aims to reduce side effects by giving a high dose only to the part of the prostate where cancer is clearly seen on MRI and a lower dose to the rest of the prostate, which looks normal. Although the healthy‑looking part of the prostate may still contain tiny cancer cells that cannot be seen on scans, we believe a moderate dose will be enough to treat those.

The study will test this new approach in a randomised trial. One group will receive this “focused” radiotherapy, and the other will receive the standard approach where the whole prostate gets the same dose. The study will look at side effects and how well the cancer is controlled over time.