A randomised controlled trial of high dose versus standard dose conformal radiotherapy for localised prostate cancer

What’s the safest and most effective dose of radiotherapy for men with prostate cancer?

What was this study about?

Radiotherapy is often given to men with prostate cancer. Newer methods of giving radiotherapy are being developed all the time. In the late 1990s, it became possible to give "conformal radiotherapy" in many centres across the UK. This meant that the radiotherapy beam could be better shaped, so that the prostate tumour would be irradiated, but the normal tissue surrounding the prostate would receive lower doses of radiation.

The RT01 trial investigated whether giving higher doses of radiotherapy would be safe and effective. RT01 was a randomised controlled trial.. Men who agreed to join the study were randomly allocated into one of two groups. Men in one group were given the standard dose of radiotherapy. Men in the other group received the higher dose.

What difference did this study make?

We found that giving men the higher dose of radiotherapy helped to better prevent prostate cancer coming back and reduced the need for additional hormone treatment later on.

Radiotherapy can cause short-term side-effects around the time that radiotherapy is given and longer-term side-effects many months after radiotherapy. In the short-term, we found that most people on each dose had bladder and bowel side-effects during radiotherapy. In both groups, the side-effects quite quickly improved after radiotherapy was finished.

In the longer-term, we found that men who received the higher dose were more likely to continue to have problems with their bowels. Long-term bladder problems were the same for both groups of men. There was some evidence that general physical well-being was a little worse in the higher dose group.

This study has helped us to measure the risks and benefits of higher dose radiotherapy. Like all good treatments there are good sides, like the better cancer outcomes, and downsides, like the increased bowel problems. Overall, we believe that the benefits reported so far outweigh the risks for most men. In future, it’s likely that more men will be offered the higher dose of radiotherapy. Information from this study will help men to choose their treatment.

The findings were published in the Lancet Oncology Journal, you can read them here. 

Type of study

Randomised trial

Contact details


Who funded the study?

The Medical Research Council.

When did it take place?

The trial recruited patients between January 1998 and December 2001. The first results were published in 2007. Updated results were published in early 2014.

Where did it take place?

Hospitals throughout the UK and some hospitals in Australia and New Zealand.

Who was included?

862 men who had early stages of prostate cancer that had not spread to other parts of the body and who had chosen radiotherapy as their main treatment.