Prostate cancer scan is 'a big leap forward'

20th January 2017 – A new test to detect prostate cancer is being hailed as the biggest leap forward in diagnosing the disease in decades.

Doctors say an advanced type of magnetic resonance imaging (MRI) scan could help around a quarter of men avoid an unnecessary biopsy and reduce the number who are over-diagnosed.

However, campaigners say many men will be unable to get the test because of a shortage of scanners and skilled operators in the NHS.

Flawed diagnosis techniques

The standard test for prostate cancer is called the prostate-specific antigen (PSA) test. High levels of PSA may indicate prostate cancer. However, the test is not always accurate and may indicate non-cancerous conditions too. For this reason, many men undergo unnecessary biopsies, in which a small sample of tissue is removed and examined for cancerous cells.

The biopsies carry the risk of side-effects, including bleeding, pain and infections.

Over 100,000 prostate biopsies are carried out in the UK each year.

A study in the medical journal The Lancet involved 576 men with suspected prostate cancer who underwent multi-parametric MRI scans (mp-MRI).

The technique provides information about the cancer's size, how densely packed its cells are and how well connected it is to the bloodstream. This information can help form a picture of whether the cancer is aggressive or harmless.

More accurate results

The results of the trial, called PROMIS, showed that 27% of the men did not need to undergo a biopsy.

They also showed that scanning accurately diagnosed 93% of the aggressive cancers, compared with just 48% when the most commonly used biopsy technique was carried out.

The research team, led by University College London (UCL), says scanning could be used to identify men who have harmless cancers and don't need an immediate biopsy. Instead, they could be monitored by their doctors.

Lead researcher Dr Hashim Ahmed from UCL says in a statement: "Our results show that mp-MRI should be used before biopsy.

"Our study found that using the two tests could reduce over-diagnosis of harmless cancers by 5%, prevent 1 in 4 men having an unnecessary biopsy, and improve the detection of aggressive cancers from 48% to 93%."

Commenting on the research in a statement, Ros Eeles, professor of prostate cancer genetics at the Institute of Cancer Research, which helped fund the trial, says: "This is a very important study that compares our current standard practice for men who have raised levels of PSA in the blood – which requires them to undergo an invasive prostate biopsy – with a new method, using MRI as an added step to diagnose the disease.

"We are searching for better ways to diagnose prostate cancer, the commonest cancer in men in the UK, since PSA alone is an imperfect test. This study provides ground breaking data that the addition of a multi-parametric MRI can be used in the diagnostic pathway after PSA to better predict who would most benefit from prostate biopsy."