Prostate cancer screening tests in men with no symptoms do not save lives
Prostate cancer is the most common cancer in men in the UK, but there is no screening program because of uncertainty about the screening blood test, prostate specific antigen (PSA). About 75% of men with an abnormal PSA test result do not have prostate cancer, and some have a small and slow-growing low-risk tumour that may never cause trouble. Conversely, about 15% of men with a normal PSA test result do have prostate cancer.
The results of the largest trial yet to settle the balance of risks and benefits of PSA screening was published in the Journal of the American Medical Association on 6 March 2018. The study was led by Richard Martin, Professor of Clinical Epidemiology in the University of Bristol. It involved more than 400,000 participants registered with 573 general practices across the UK. Practices were randomised so that their male patients aged 50 to 59 years either had an invitation to have a single PSA test or received their usual care as controls. About 40% of those invited to participate accepted, 64,436 men providing a PSA result. The clinical histories of these men and those in the control group were recorded for an average of 10 years, follow-up being very nearly complete. A standard approach to the diagnosis of prostate cancer was used in both groups of practices, including a 10-core prostate biopsy in those with a raised PSA result.
Prostate cancer was diagnosed during the 10-year follow-up in 4.3% of those screened and 3.6% of the control group. Biopsy results showed that the tumours were low-risk in 1.7% of those screened and in 1.3% of controls. The death rates from prostate cancer were 0.29% in both groups. The authors concluded that there was no significant difference in prostate cancer mortality after a median follow-up of 10 years but the detection of low-risk prostate cancer cases increased.
Professor Richard Martin said "Our large study has shed light on a highly debated issue. We found that offering a single PSA test to men with no symptoms of prostate cancer does not save lives after an average follow-up of ten years. The results highlight the multitude of issues the PSA test raises - causing unnecessary anxiety and treatment by diagnosing prostate cancer in men who would never have been affected by it and failing to detect dangerous prostate cancers.”
Well men who are concerned about the risks and benefits of having a PSA measurement are able to obtain an information leaflet from their GP, and may request a test if they wish. Cancer Research UK, who funded the screening study with the Department of Health and Social Care, has requested that the leaflet be updated to reflect the new study’s findings.