Image copyright Getty Images Image caption MRI scans can safely reduce the numbers of men needing an invasive biopsy

A large new trial is testing whether MRI scans could be an effective way to screen men for prostate cancer, in a similar way to mammograms offered to women to check for breast cancer.

In this article for the BBC, leading expert Prof Mark Emberton explains why finding a suitable screening method for this common male cancer is vital but has proved difficult so far.

"Prostate cancer is the most common form of cancer in men, with around 130 new cases diagnosed in the UK every day and more than 10,000 men a year dying from the disease.

"Unfortunately, the way we currently spot the disease is not very precise.

"Traditionally, we have used a blood test looking for raised levels of prostate-specific antigen (PSA) and then carried out a biopsy which means taking some tissue from the prostate gland to examine under the microscope.

"But PSA levels are not a reliable indicator of prostate cancer - about 75% of men who get a positive result are not found to have cancer, while it misses the cancer in about 15% of men with prostate cancer.

"So we currently diagnose cancers that are harmless, leading to unnecessary investigations and operations, and we miss cancers that are harmful, leaving the disease to multiply and move around the body unchecked."

Is imaging the answer?

The ReIMAGINE project, which Prof Emberton is part of, is being led by University College London and includes researchers at Imperial College, Kings College London and clinicians at UCLH.

Prof Emberton says: "By using magnetic resonance imaging (MRI), we hope to change how prostate cancer is diagnosed and then treated.

"We know from international research that MRI can markedly and safely reduce the numbers of men needing an invasive biopsy.

"This research recently led to changes in official health guidelines, with MRI now recommended as the first test for men referred to hospital by their GP with suspected prostate cancer.

"As part of the project, we want to see if MRI could also be an effective tool for screening healthy men, in the same way there are national NHS screening programmes to detect signs of breast or cervical cancer."

How is it being trialled?

From this month, 300 men, aged between 50 to 75 years old, will be randomly selected from London GPs and sent a letter explaining that they can join the trial.

Each patient will be given a PSA blood test and a 10-minute MRI scan.

Image caption Hundreds of men will be involved in the trial using MRI scans

By combining the results of the PSA test and analysing the MRI images, radiologists and urologists will work together to more accurately diagnose whether a man has signs of prostate cancer or not.

Why is this important?

Prof Emberton explains: "Capturing harmful cancer at the earliest opportunity will lead to quicker treatments, significantly better outcomes for those men affected and ultimately save lives.

"It will also reduce the numbers of men undergoing biopsy, which in turn will reduce NHS costs and free up staff time.

"The other important aspect of the study will be to examine whether, combined with cutting-edge techniques such as genomics and machine learning, MRI scans can replace prostate biopsies.

"Prostate cancer patient groups are a hugely important part of the study, and the prospect of achieving a large reduction in biopsies is a significant wish - as they can have serious side effects in patients, including pain, bleeding and infections.

"Our team aims to recruit 1,000 men with medium to high risk cancers to find out if MRI can be combined with other high-tech diagnostic tests to predict cancer progression.

"The ultimate aim is to develop tests that are better than biopsies for targeting the right cancer treatment to the right person - including determining if they don't need treatment.

"We are hopeful that, as a result of our study, we might be in a position to get rid of the biopsy and advise men on their risk based on and MRI and a blood test alone.

"Targeting and treating prostate cancer using advanced imaging is one of the most disruptive discoveries I can recall in men's health and draws on multi-disciplinary expertise from university researchers and clinicians across the globe.

"By working together, we can and will continue to make significant breakthroughs in tackling cancer."