Hi-tech prostate cancer test to improve detection 

Mar 2022

University College London researchers discover a breakthrough in prostate cancer screening that will lead to better diagnosis.

SCIENTISTS have developed a new high-tech prostate cancer test that is safer and more accurate than existing methods. 

The breakthrough could pave the way for countries like the UK and US to introduce national screening programmes for the disease – similar to those in place for breast and cervical cancer. 

Research published in the Journal of Medical Screening shows the test – developed by a team at University College London – detects 90 per cent of cancers before any symptoms show but also reduces the rate of false positives by up to 75 per cent compared to current checks. 

False positives are where cancer is wrongly diagnosed, or a tumour is present but is so slow-growing that it needs no immediate medical treatment and may never actually cause ill health. 

The high rate of false positives is one reason why the existing prostate specific antigen, or PSA, blood test is not routinely used to screen men for the disease. 

Although PSA testing can find aggressive prostate tumours that need urgent treatment, levels can be elevated for reasons other than cancer and it gives a false positive result in around 70 per cent of cases. As a result some men undergo invasive procedures – such as biopsies – that cause unnecessary discomfort and worry. 

PSA tests also have a high false negative rate – where results wrongly conclude a man is cancer-free. It’s thought this happens in up to one in seven cases. 

Researchers have been searching for better ways to spot the disease early and save more lives. 

Prostate cancer leads to the death of more than 34,000 men a year in the US and 11,500 a year in the UK. 

In the latest breakthrough, UCL scientists combined standard PSA testing with measures of another prostate cancer marker, called human kalliknein peptidase, or hK2. 

Like PSA, hK2 is not considered an accurate enough signal on its own to diagnose prostate cancer. 

But by combining it with PSA results and then setting a ‘risk threshold’ – where blood levels of both markers are significantly above average according to a man’s age – they were able to correctly identify 90 per cent of cancer cases and at the same time reduce the false positive rate to just over 1 per cent. 

The big advantage, researchers claim, is this combined method screens men on the basis of their overall risk,  rather than the results of a single test, as with PSA. 

The UCL team came up with the findings after analysing data and blood samples from more than 21,000 men who took part in a long-running health study spanning 40 years. 

They analysed prostate cancer markers in blood samples of 571 men who later died from or with prostate cancer, comparing these with a control group of 2,169 men who were never diagnosed with the disease. 

Scientists believe the two-in-one-test could be carried out every five years to assess a man’s risk of cancer. 

Professor Sir Nicholas Wald, a leading epidemiologist who spearheaded the study, said: ‘This method would make screening for prostate cancer safer and more accurate, reducing overdiagnosis and overtreatment. 

‘If that’s successful, we believe it should be considered as part of a national screening programme for all men.’ 

Prostate Cancer UK president Professor Roger Kirby welcomed the new test. 

‘It carries the genuine promise of significantly reducing the death rate from this most common cancer in men,’ he said. 

‘The next step is to test it with a pilot project inviting healthy men for screening. 

‘If that’s successful, we believe it should be considered as part of a national screening programme for all men.’

Source https://journals.sagepub.com/doi/10.1177/09691413221076415 copy