Researchers from the Universities of Bristol, Oxford and Cambridge have revealed that a prostate-specific antigen (PSA) blood test for prostate cancer has a small impact on reducing deaths and can lead to overdiagnosis and missed early detection of aggressive forms of cancer.
Published in the Journal of the American Medical Association and funded by Cancer Research UK (CRUK), the CAP trial studied over 400,000 men aged 50 to 69 years from 570 GP practices in the UK.
Currently the second biggest cause of death for men in the UK, responsible for around 12,000 deaths a year, prostate cancer is a disease that occurs when malignant cells grow in the prostate gland.
Widely used for diagnosis, a PSA blood test measures the amount of PSA, a protein made by the prostate gland, in the blood. If high levels of PSA are indicated, it could suggest the presence of prostate cancer.
However, research has shown that the PSA test can sometimes increase the detection of low-risk prostate cancers and miss some high-risk cases.
Researchers followed up with the male participants for 15 years and compared 189,386 men who were invited to have a one-off PSA test to 219,439 men who were not.
The team found prostate cancer in 4.3% of the screened group compared to 3.6% in the non-screened grou p, while nearly seven men out of every 1,000 in the group invited for screening died from the disease compared to nearly eight men out of every 1,000 in the group who had not.
Additionally, results demonstrated that an estimated one in six cancers was overdiagnosed by the PSA screening test.
Professor Richard Martin, lead author and CRUK scientist, University of Bristol, commented: “The small reduction in prostate cancer deaths by using the test to screen healthy men does not outweigh the potential harms.
“We need to find better ways to spot aggressive prostate cancers, so we can treat them early.”
