PSA levels 'fail to pick out prostate cancer'
Prostate-specific antigen levels fail to predict the presence of cancer and are only weakly related to tumour volume, a UK study concludes.
The researchers insisted PSA was largely produced by benign prostatic hyperplasia, and was a poor screening tool in asymptomatic men.
Their study found PSA levels were not significantly higher in men with prostate cancer than in those who had had their prostates removed but did not have cancer.
Levels were non-significantly higher – at 3.1ng/ml compared with 1.1ng/ml – but this was skewed by four large-volume cancers with high PSA levels.
Despite this, PSA levels correlated only poorly with tumour volume, according to the study, published in the latest issue of BJU International.
Study leader Mr Timothy Christmas, consultant surgeon at the department of urology, Charing Cross Hospital, said: 'This is further evidence that most of the PSA in prostates with cancer is produced by benign prostatic hyperplasia.
'PSA is therefore confirmed as a poor screening tool, which appears to cause a serendipitous detection of cancer.'
The researchers called for PSA to be abandoned as a trigger for biopsies, although they admitted this would be a 'major change' in management strategies for the disease.
Dr James Kingsland, member of the scientific reference group on prostate cancer for the National Screening Committee, said: 'It's exactly what the national cancer screening programme is trying to instil in general practice and male patients. It's just a tool to aid in diagnosis or establish how effective cancer treatments are.'
Dr Kingsland, a GP in Wallasey, Merseyside, added GPs had the right to refuse tests to demanding patients: 'We have never had tests on demand – it's the clinician's decision.
'The patient could have an abnormal test and then you're condemning them to have a prostate biopsy. There's so much danger in doing it.'The researchers evaluated data on 97 prostates removed at radical cystoprostatectomy and detected prostate cancer in 60 per cent of specimens.
National Screening Committee's position on PSA testingNational Screening Committee's position on PSA testing National Screening Committee's position on PSA testing
• Prostate cancer screening can be provided on request, provided the man fully understands the lack of quality evidence about the benefits and risks of testing
• Ensure people considering a PSA test are given all the facts about the risks, using methods for ensuring informed choice
• PSA testing to an explicit standard should be available to all who agree to have a test
• Patients must have access to systematic and standardised follow-up pathways if their tests are above the threshold