MRI scans are more effective than blood tests at spotting prostate cancer and could “significantly” reduce deaths from the disease, new research has suggested.
Prostate cancer is the most common type of the disease found in men, and those aged over 50 can request a blood test that measures the level of a protein called PSA, or prostate-specific antigen, if they have symptoms.
Scientists say the blood test has been linked to over-diagnosis and over-treatment of low-risk cancer.
The new Reimagine study invited 303 men aged between 50 and 75 to have screening MRIs and PSA tests. The scans diagnosed cancer requiring treatment more often in men who would have been reassured they were healthy using the blood test readings alone.
Of the total, 48 men, or 16 per cent, had an MRI that indicated the presence of prostate cancer despite having a median PSA density.
Of that group, 32 had lower PSA levels than the current screening benchmark of 3ng/ml, meaning they would not have been referred for further investigation.
But after NHS assessment, 29 men were diagnosed with cancer that required treatment, 15 of whom had serious cancer and a PSA of less than 3ng/ml.
Only three men, 1 per cent, were diagnosed with low-risk cancer that did not require treatment.
The study was led by University College London, University College London Hospitals NHS Foundation Trust and King's College London and is published in the medical journal BMJ Oncology.
Prof Caroline Moore, consultant surgeon at UCLH, chief investigator of the study and NIHR research professor, said the finding is “sobering” and “reiterates the need to consider a new approach to prostate cancer screening”.
“Our results give an early indication that MRI could offer a more reliable method of detecting potentially serious cancers early, with the added benefit that less than 1 per cent of participants were 'over-diagnosed' with low-risk disease,” she added.
Prof Mark Emberton, consultant urologist at UCLH, said: “The UK prostate cancer mortality rate is twice as high as in countries like the US or Spain because our levels of testing are much lower than other countries.
“Given how treatable prostate cancer is when caught early, I'm confident that a national screening programme will reduce the UK's prostate cancer mortality rate significantly. There is a lot of work to be done to get us to that point, but I believe this will be possible within the next five to 10 years.”
Nick James, a professor of prostate and bladder cancer research at the Institute of Cancer Research in London, said the study “further reinforces the value of MRI in the diagnostic pathway for prostate cancer”.
“The well-known limitations of the old PSA-based screening studies of over-diagnosis and linked over-treatment are increasingly mitigated by the use of MRI,” he added.
“Similarly, MRI can also spot cases of prostate cancer in patients with normal PSA levels, who would have been missed using PSA-only screening programmes.”
Prof Sir Mike Richards, chairman of the UK National Screening Committee (NSC), said the organisation does not currently recommend prostate cancer screening “because there is no clear evidence that the benefits outweigh the harms”.
However, it is preparing to look at various proposals.
He added: “The UK NSC will soon commission a major piece of work to consider six prostate cancer screening proposals that were submitted during its annual call for topics.
“These include targeted and risk-stratified screening proposals for screening groups of men at higher risk due to factors such as ethnicity and family history.”
Simon Grieveson, assistant director of research at Prostate Cancer UK, said: “MRI scans have revolutionised the way we diagnose prostate cancer, and it's great to see research into how we might use these scans even more effectively.
“These results are extremely exciting, and we now want to see much larger, UK-wide studies to understand if using MRI as the first step in getting tested could form the basis of a national screening programme.”
Another trial, known as Limit, is being conducted with a much larger number of patients, which the research team said is the “next step towards a national prostate screening programme”.
The trial will also attempt to recruit more black men, after the team behind Reimagine found they were much less likely to respond to the invitation to screening than others.
Saran Green of King's College London said: “One in four black men will get prostate cancer during their lifetime, which is double the number of men from other ethnicities.
“Given this elevated risk, and the fact that black men were five times less likely to sign up for the Reimagine trial than white men, it will be crucial that any national screening programme includes strategies to reach black men and encourage more of them to come forward for testing.”
