Prostate cancer blood test could more accurately spot men who need a biopsy
A new test that measures blood protein levels, DNA, a prostate examination and facts about a man’s background could more accurately predict which men need a prostate biopsy, Swedish researchers have found.
“If we can do this early testing accurately, then we should also be able to spare those men with prostate cancers that wouldn’t ever cause them any harm from the problems of a biopsy" - Professor Malcom Mason, Cancer Research UK
The test also appeared to be able to spot high risk prostate cancers, but experts cautioned that this would need confirming in clinical trials.
Current testing for prostate cancer relies on measuring blood levels of a protein called prostate specific antigen (PSA). But this can be unreliable, resulting in some men having unnecessary biopsies and can lead to men being diagnosed and treated for prostate cancers that may never have harmed them in their lifetime (known as ‘overdiagnosis’).
To address this, scientists at the Karolinska Insitute in Sweden combined PSA measurement and a prostate exam, along with analysis of more than 200 genetic markers linked to prostate cancer, and clinical information such as age and family history, to try to develop a more accurate test.
In a study of 58,818 men aged 50-69, published in The Lancet Oncology, the researchers found that the test, known as STHLM3, reduced the number of biopsies given to men who received it by around 30 per cent, compared to relying solely on PSA measurement.
Professor Malcom Mason, Cancer Research UK’s prostate cancer expert, said this combined approach was precisely what was needed for more accurate diagnosis.
“We need to find better ways of identifying those men who actually need a prostate biopsy so we can make an earlier diagnosis of potentially aggressive prostate cancer. So this is precisely the sort of approach that’s needed,” he said.
“If we can do this early testing accurately, then we should also be able to spare those men with prostate cancers that wouldn’t ever cause them any harm from the problems of a biopsy,” he added.
Not only was the STHLM3 test found to be more reliable than the standard PSA blood test, it also picked up some potentially high risk cancers in men with low PSA values that may have otherwise been missed.
Casey Dunlop, health information officer at Cancer Research UK, said the findings were “a step in the right direction”, but stressed that more questions need to be answered before such a test like could be reliably used to determine who needs a biopsy.
“It shows the potential of combining the PSA test with other biomarkers, and genetic and clinical information to more accurately identify men with potentially low-or high risk prostate cancers, compared with the PSA test alone,” she added.
Both Mason and Dunlop agreed that large-scale clinical trials would be needed to prove that the new test could reduce the number of men dying from prostate cancer, as well as addressing the challenge of overdiagnosis and overtreatment.
“This sort of targeted screening of high risk men is very different from screening a whole population of healthy individuals. But identifying those at higher risk may be a challenge. And this approach would need to be tested in larger clinical trials to prove it could avoid men being diagnosed and treated unnecessarily,” said Mason.
Lead scientist Professor Henrik Gronberg, from the Karolinska Institute in Sweden, said the results were promising.
“If we can introduce a more accurate way of testing for prostate cancer, we'll spare patients unnecessary suffering and save resources for society,” he added.