There is no single, diagnostic test.
Doctors make a diagnosis based on various measures.
This can include a prostate-specific antigen (PSA) blood test and a scan, as well as a biopsy, which involves taking a small tissue sample to examine in the laboratory.
PSA tests are not routinely used to screen healthy men for prostate cancer because the results can be unreliable.
A high PSA does not always mean cancer. It can go up if there is an infection, for example.
And some men with a raised PSA may have a prostate cancer that would not have caused problems or needed treatment, causing unnecessary worry and further investigations.
Researchers have repeatedly looked at whether it would be beneficial to introduce the screening. Those studies, overall, show that offering all men of a certain age a PSA test would only lead to a small reduction in the number of men dying from prostate cancer.
Men over 50 can usually ask their GP for a PSA blood test if they want to. Your GP will explain the potential benefits and risks of having a PSA test.
If you decide you want a PSA test, you should refrain from sexual activity and vigorous exercise, such as cycling, in the two days beforehand as this can affect the results.
Doctors are looking at whether adding in MRI scans to PSA tests might improve the situation.
