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A long-running clinical trial of how best to treat men diagnosed with early prostate cancer found that active monitoring was as effective as surgery or radiotherapy in preserving life. Active monitoring, sometimes called 'watch and wait', means that men have regular tests, and only have surgery or radiotherapy if the cancer progresses.

In the trial, surgery and radiotherapy both reduced the likelihood of the cancer progressing compared to active monitoring. But these treatments were associated with damage to sexual and urinary function.

The Prostate Testing for Cancer and Treatment (ProtecT) study included men aged 50-69 years diagnosed with prostate cancer which had not spread beyond the prostate (localised). It was diagnosed following a simple blood test. Ten years after diagnosis, 99% of men were still alive, regardless of whether they had been allocated to surgery, radiotherapy or active monitoring.

Prostate cancer usually progresses slowly and there is a long running debate on the best course of action for men with localised prostate cancer. These results will help individual men and their clinicians decide together on the most appropriate treatment for them.

What’s the issue?

Prostate cancer is the most common cancer in men. It is often found by blood tests showing raised levels of a marker called prostate-specific antigen (PSA). Cancer is confirmed or ruled out by a biopsy in which a small sample of the prostate is removed and examined under a microscope.

The PSA test became available in the late 1980s and led to a surge in diagnoses. But it frequently detects small cancers that would never cause harm. It is difficult to recognise those early cancers which will go on to become harmful and tell them apart from those which will not.

When prostate cancer is localised, the conventional radical treatments are surgery or radiotherapy. Both these treatments carry side effects including leaking urine (incontinence) and difficulty getting an erection. Another option is active monitoring, which involves regular PSA measurements, clinical examinations, scans and sometimes biopsies. Surgery or radiotherapy are offered only if the cancer progresses.

Before this study, there were no reliable data to directly compare the effects of active monitoring with surgery or radiotherapy.

What’s new?

The study included 82,429 men aged 50–69 years who agreed to have a PSA test. Some 2664 were diagnosed with localised prostate cancer, and of this group, 1643 agreed to be randomly allocated to surgery, radiotherapy, or active monitoring. Urinary and sexual function was assessed by questionnaires completed by the men.

The results showed that, ten years after diagnosis:

  • 99% of men were alive in each of the three groups
  • compared with active monitoring, surgery and radiotherapy reduced the risk of disease spreading outside the prostate by half
  • urinary leakage and sexual function were worst after surgery
  • sexual and bowel functions were most affected by radiotherapy
  • More than half (55%) men on active monitoring moved to a radical treatment but many (44%) remained disease free and avoided the side effects of treatments.

The study found that overall, quality of life was similar across all groups. Men on active monitoring had an expected gradual decline in their urinary and sexual function over time. The researchers concluded that longer follow-up is needed to determine the most cost-effective treatment for localised prostate cancer over a man’s lifetime.

Why is this important?

The findings give individual men and specialists (urologists and oncologists) more information on which to base the decision on the best approach to localised prostate cancer. Men need to weigh up the possible benefits in cancer control with surgery and radiotherapy, against a higher risk of spread but fewer side effects with active monitoring. The study found that two in five men in the active monitoring arm (44%) never needed surgery or radiotherapy and were spared the negative effects..

The results have already helped to change guidelines across the world on how to deal with prostate cancer. NICE, for example, updated its guidance in 2019 to say that patients should be able to consider active monitoring.

The study results have been long-awaited because the disease is slow to progress, and large numbers of men must be studied to detect small differences. This trial is the first randomised controlled comparison of all conventional treatments.

What’s next?

The trial has continued since these results were collected. The research team is currently analysing data after a further five years, so a total of 15 years’ follow up is eagerly awaited.

This will help show the longer-term effects of these treatment options on survival and quality of life. This is vital information to help men diagnosed with the disease and their doctors to choose whether to treat the cancer and how.

You may be interested to read

The full study: Hamdy F, and others. Active monitoring, radical prostatectomy and radical radiotherapy in PSA-detected clinically localised prostate cancer: the ProtecT three-arm RCT. Health Technology Assessment. 2020;37:1-176

Economic analysis: Noble SM, and others. The ProtecT randomised trial cost-effectiveness analysis comparing active monitoring, surgery, or radiotherapy for prostate cancer. British Journal of Cancer. 2020;123:1063–1070

NICE guidance: Prostate cancer: diagnosis and management [NG131] (2019), covering communication and patient-centred care throughout the patient journey


Funding: The study was funded by the NIHR Health Technology Assessment programme.

Conflicts of Interest: Several authors report fees and support from various pharmaceutical companies.

Disclaimer: NIHR Alerts are not a substitute for professional medical advice. They provide information about research which is funded or supported by the NIHR. Please note that views expressed in NIHR Alerts are those of the author(s) and reviewer(s) and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.

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