This trial showed that only a few less men who were invited for a PSA test died because of prostate cancer.
There was a small difference between the group of men who were invited to have a PSA test, and those who weren’t.
Results
This trial recruited over 400,000 men who had not been diagnosed with prostate cancer at the start of the trial. The men taking part were placed into 1 of 2 groups at random, and:
- about half were offered a PSA blood test
- about half were not offered a PSA test (the control group)
Just under 200,000 men were invited to see a nurse to discuss having a PSA test to begin with. Of these:
- more than 70,000 saw a nurse
- more than 60,000 had a PSA blood test
- just under 7,000 had a raised PSA level
- just under 6,000 had a biopsy of their prostate
- just under 3,000 were diagnosed with prostate cancer
The team looked at the long term results in 2021. The men taking part had been in the trial between 12 and 19 years by then. The median 
time they’d been in the trial was 15 years.
Prostate cancer risk
The team looked at the risk of being diagnosed with prostate cancer 15 years after joining the trial.
They found that out of every 1,000 men it was:
- 71 men in the group who had been offered a PSA test
- 69 men in the control group who were not offered a PSA test
They then looked at the risk of dying because of prostate cancer. Out of every 1,000 men this was:
- 7 men in the group who had been offered a PSA test
- 8 men in the control group who were not offered a PSA test
They also looked at the total number of men that had died of any cause. This could have been because of prostate cancer. But it could have been for any other reason. It was just over 230 out of every 1,000 men in each group.
The results showed that the men who were diagnosed with prostate cancer after having the PSA test as part of the trial, were more likely to:
- be younger when they were diagnosed
- have cancers that were low risk
- have cancer that had not spread
So it was more likely that they had prostate cancer diagnosed that wouldn’t need treatment or cause problems during their lifetime.
Conclusion
The trial team concluded that a few less men in the PSA test group died because of prostate cancer. But the difference between the two groups was very small.
Out of every 1,000 men who were invited for a PSA test, one less man died of prostate cancer. There was no difference in the number who died overall.
The team point out that it is important to balance the potential benefits of screening with the risks of being overdiagnosed with prostate cancer that would never cause harm in someone’s lifetime. The team say this overdiagnosis can affect quality of life and having unnecessary treatment can cause side effects. These possible side effects include infection after a prostate biopsy , bladder and bowel problems and problems getting an erection.
The team say this trial provides men aged 50 to 69 years with information about the potential benefits and risks of having a PSA test. They point out that this information can now be used to support decision making about whether or not to have a PSA test.
More detailed information
There is more information about this research in the references below.
Please note, the information we link to here is not in plain English. It has been written for healthcare professionals and researchers.
PSA Screening and 15-year Prostate Cancer Mortality: A secondary analysis of the CAP randomized clinical trial.
Richard M. Martin and others
Journal of the American Medical Association (JAMA), published online 6th April, 2024.
Effect of a Low-Intensity PSA-Based Screening Intervention on Prostate Cancer Mortality: The CAP Randomized Clinical Trial.
Richard M Martin and others
Journal of the American Medical Association (JAMA), 2018. Volume 319, issue 9, pages 883-895.
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 ) and published in medical journals. We have not analysed the data ourselves.
