A trial comparing treatment approaches for prostate cancer (ProtecT)

Cancer type:

Prostate cancer




Phase 3

This trial was done to compare 3 treatment options for prostate cancer that is contained within the prostate gland. This is called localised cancer.

The treatment options were radiotherapy, surgery and active monitoring. The trial was done because doctors weren’t sure if any one treatment was better than another for men in this situation.

It was open for people to join between 1999 and 2009. The team published long term results in 2023.

More about this trial

This trial was for men aged between 50 and 69 who had been diagnosed with prostate cancer following a PSA blood test. They all had prostate cancer that was contained within the prostate. 

In this trial, they compared:

Active monitoring involves seeing a doctor or nurse regularly, and having PSA tests to monitor whether the cancer has grown. You may hear this called active surveillance. People can have surgery or radiotherapy if there are any signs that the cancer is beginning to change or grow.

The main aims of this trial were to find out:

  • which treatment was best for localised prostate cancer
  • how each treatment affected quality of life

Summary of results

The trial team found that all 3 options worked well for men with localised prostate cancer. Each treatment had different side effects, so it’s important to weigh up the pros and cons of each one.

Trial design
The men taking part in this trial all had prostate cancer that was contained within the prostate gland. Most of the men had a low or medium risk that their cancer would grow.

A total of 1,643 men joined the trial. They were put into 1 of 3 groups at random. Neither they nor the doctors could decide which group they were in.

There were:

  • 545 men in the radiotherapy group
  • 553 men in the surgery group
  • 545 men in the active monitoring group

The research team looked at whether the prostate cancer had grown or spread over time. And at how many people were living, an average of 15 years after the trial started.

The research team looked at the long term results in 2020. The men taking part had been in the trial an average of 15 years by then.

How well treatment worked
They looked at how many men had prostate cancer that had spread to another part of the body. They found it was higher for men who had active monitoring:

  • 27 men who had radiotherapy (5.0%)
  • 26 men who had surgery (4.7%)
  • 51 men who had active monitoring (9.4%)

But when they looked at how many men had died because of their prostate cancer, they found it was low and similar in all 3 groups:

  • 16 men who had radiotherapy (2.9%)
  • 12 men who had surgery (2.2%)
  • 17 men who had active monitoring (3.1%)

They also looked at how many men had died in total, not just because of their prostate cancer. This was also similar in the 3 groups. 

This means that men with low or medium risk localised prostate cancer can live a long time whether they have surgery, radiotherapy or active monitoring. 

It is important to remember that these results are not for men who have a high risk of their cancer growing, or have cancer that has spread. Men in this situation need treatment straight away.

Side effects and quality of life
The research team asked the men to complete questionnaires about side effects they were having and their quality of life. These are called patient reported outcome measures or PROMs.  

The questionnaires asked about the effect on quality of life in 4 main areas (domains). These were:

  • urinary function
  • sexual function
  • bowel function
  • health related quality of life

The men completed questionnaires before, during and after treatment. The team have the results of these questionnaires for most people, every year up to 12 years after they joined the trial. 

It is important to remember that men in this trial may have had other treatments to treat their cancer or help with symptoms they were having. These treatments can also cause side effects.

Urinary function
The questionnaire asked about urinary symptoms, including leakage. One way to assess urinary leakage (incontinence) is whether people need to use pads. The research team looked at the number of men who used at least 1 pad each day to control urinary leakage.

They found this was higher in those who had surgery, up to 12 years after joining the trial:

  • 29 out of 379 men who had radiotherapy (8%)
  • 91 out of 386 men who had surgery (25%)
  • 42 out of 368 men who had active monitoring (11%)

They asked the men whether urinary leakage interfered with their daily lives. Some men said it interfered a moderate or large amount. This was higher in those who had surgery:

  • 25 out of 374 men who had radiotherapy (7%)
  • 59 out of 385 men who had surgery (15%)
  • 41 out of 361 men who had active monitoring (11%)

Sexual function
The questionnaire asked men about the effect of treatment on their sex life. The impact was greatest in those who had surgery. 

They asked the men if they had an erection that was firm enough for intercourse.  After 7 years, this was possible for fewer men who had surgery:

  • 123 out of 453 men who had radiotherapy (27%)
  • 82 out of 459 men who had surgery (18%)
  • 133 out of 438 men who had active monitoring (30%)

They asked the men how much impact problems with sex life had on their quality of life. Some men said it had a moderate or large impact. This was higher in those who had surgery, 7 years after treatment:

  • 156 out of 452 men who had radiotherapy (35%)
  • 213 out of 457 men who had surgery (47%)
  • 169 out of 435 men who had active monitoring (39%)

When they looked at the results at 12 years, there was little difference between the groups.

Bowel function
The questionnaire asked the men about bowel symptoms. Most were similar in all groups. 

One question asked about bowel leakage. The number of men who had bowel leakage at least once a week was higher in those who had radiotherapy, 12 years after treatment:

  • 32 out of 266 men who had radiotherapy (12%)
  • 17 out of 263 men who had surgery (6%)
  • 15 out of 263 men who had active monitoring (6%)

Health related quality of life
The questionnaire asked the men about:

  • physical health
  • mental health
  • anxiety
  • depression
  • overall quality of life

The results showed that these were similar for all 3 treatment groups. 

Overall conclusions
The research team concluded that the number of men living 15 years after being diagnosed with low or medium risk localised prostate cancer was high. It was not affected by the treatment the men had when they were first diagnosed. 

The research team said that this was reassuring, and each treatment had pros and cons. 

They say that taking time to decide on a treatment plan won’t affect long term outcomes. There is no need to rush into a decision about treatment. Each man should discuss all the benefits and side effects of each treatment approach with their doctor. Together they can decide which treatment option is best.

The team is planning a longer term analysis of the results. They plan to look at how well treatment has worked after an average of 20 years. And at patient reported outcomes after an average of 15 years. We hope to update this page once these results are available.

More detailed information
There is more information about this research in the references below. 

Please note, the information we link to below is not in plain English. It has been written for healthcare professionals and researchers.

Fifteen-Year Outcomes after Monitoring, Surgery, or Radiotherapy for Prostate Cancer
FC Hamdy, JL Donovan and others
The New England Journal of Medicine (NEJM), published online March 2023.

Patient-Reported Outcomes 12 Years after Localized Prostate Cancer Treatment
JL Donovan, FC Hamdy and others
NEJM Evidence, published online March 2023.

Where this information comes from    
We have based this summary on the information in the articles above. These have been reviewed by independent specialists (peer reviewed Open a glossary item) and published in a medical journal. We have not analysed the data ourselves.

Recruitment start:

Recruitment end:

How to join a clinical trial

Please note: In order to join a trial you will need to discuss it with your doctor, unless otherwise specified.

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Chief Investigator

Professor FC Hamdy
Professor JL Donovan
Professor DE Neal

Supported by

NIHR Health Technology Assessment (HTA) programme 
University of Oxford
University of Bristol
University of Cambridge
Cancer Research UK 
NIHR Oxford Biomedical Research Centre

Other information

You can read more on the ProtecT trial website.





If you have questions about the trial please contact our cancer information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:


Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Keith took part in a trial looking into hormone therapy

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"Health wise I am feeling great. I am a big supporter of trials - it allows new treatments and drugs to be brought in.”

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