New prostate test finds more tumours than PSA screening, study finds

A new test could be more effective at detecting dangerous prostate cancer than current screening methods, a study suggests.

Researchers in Sweden say a tool, known as Stockholm3, finds 90 per cent of 'clinically significant' prostate cancers, compared with 74 per cent uncovered by the standard prostate-specific antigen (PSA) test.

The PSA test, which measures levels of a protein produced by the prostate gland, is currently the main method used to assess a man's risk of prostate cancer. 

While high PSA levels can be a sign of the disease, they can also be caused by other conditions - prompting researchers to look for more accurate ways of identifying men at risk, preventing unnecessary scans and biopsies.

Prostate cancer is the most common form of the disease among men in the UK - affecting around one in eight adults and linked to around 63,000 new cases and 12,000 deaths each year. 

Men looking to protect themselves can request a PSA test from a GP, but the effectiveness of the screening has long been debated by critics because it can produce false-positive results and miss some aggressive tumours.

Now, researchers from the Karolinska Institute in Stockholm now believe Stockholm3 could be a potential answer.

The new test combines PSA measurements with genetic markers linked to a heightened prostate cancer risk, as well as additionally relevant proteins in the blood, and factors such as age, family history and previous biopsy results. 

A new test could be more effective at detecting dangerous prostate cancer than current screening methods, a study suggests

It then generates a risk score that estimates a man's likelihood of having clinically significant prostate cancer - defined in the study as anything above grade two of the disease. 

Grade two cancers, while still likely to grow slowly, are considered potentially harmful and are more likely to need treatment than tumours in grade one.

The study involved 12,670 men aged between 50 and 74 with an average age of 62, who underwent both PSA and Stockholm3 testing. 

Among those screened, 443 were diagnosed with clinically significant prostate cancer.

Researchers found that Stockholm3 bettered the standard PSA test by reducing the number of serious tumours that were missed and by also bringing down the amount of unnecessary biopsies. 

Over a follow-up period of two years, the new test missed just 10 per cent of clinically significant cancers, compared with 26 per cent for PSA screening. The rate of false positives was similar for both tests.

Stockholm3 also correctly identified nine in 10 clinically significant cancers, while this was around three in four for the PSA test. 

Authors wrote: 'In this screening cohort with short-term follow-up, Stockholm3 provided greater clinical net benefit than PSA for detecting (clinically significant prostate cancer), driven by fewer false-negative results, although follow-up was limited to 2 years.'

They add that the findings suggest the Stockholm3 test could be more accurate than standard PSA testing and reduce the need for unnecessary procedures.

Because levels of PSA can rise for other reasons than prostate cancer, such as an infection and advancing age, critics say the PSA blood test can wrongly reassure someone cancer is not present, and can lead to unnecessary scans and biopsies when levels are raised for reasons other than cancer. 

The researchers acknowledged limitations to their new research , including that only around a quarter of the men invited to participate in the screening study chose to take part. 

However, they believe their findings warrant more scrutiny, adding: 'Further investigation, including longer-term follow-up of survival and cause-specific mortality, will be needed to evaluate the long-term effect and cost-effectiveness of this screening approach. 

'If confirmed, integrating Stockholm3 into screening pathways may improve the efficiency and clinical utility of prostate cancer screening programs.'

It comes just weeks after a new study suggested an alternative approach to testing for prostate cancer using MRI scans could be more effective than current screening methods used by the NHS.