Waiting and checking is a sufficiently safe option if the MRI findings of the prostate are negative
Photo: MRI machine at the Department of Radiology © Charité | Rafael Poschmann
There are various strategies for detecting prostate cancer at an early stage: The first step is often a blood test (PSA test). If the PSA value is above a certain limit, a tissue sample is usually taken. Another option is to first look for signs of a tumour using MRI scans if cancer is suspected and only carry out a biopsy if there are any abnormalities. A study by Charité – Universitätsmedizin Berlin has investigated whether the MRI-based strategy is also safe in the long term. It concludes that patients are not exposed to any increased risk for at least three years. The study has now been published in the journal JAMA Oncology*.
In a PSA test for the early detection of prostate cancer, the amount of prostate-specific antigen (PSA) in the blood is determined. If the value is elevated, this may indicate prostate cancer – but may also be due to other causes. To be on the safe side, a punch biopsy is often carried out if PSA levels are elevated. Ten to twelve tissue samples are taken from the entire prostate with a small hollow needle and analysed – a procedure that is associated with unpleasant side effects in the days that follow as well as a certain risk of infection. ‘We therefore wanted to find out whether men whose MRI images are unremarkable can wait and observe instead of undergoing a biopsy straight away,’ explains Dr Charlie Hamm, first author of the publication and physician at the Charité Department of Radiology.
Biopsies can be avoided if MRI findings are negative
In fact, this procedure, in which regular urological check-ups followed an unremarkable MRI result, proved to be sufficiently reliable: The probability that a man with an unremarkable MRI result would not develop aggressive prostate cancer within three years was 96 per cent in the study. Only four per cent of participants were diagnosed with aggressive prostate cancer during further check-ups despite negative MRI results.
‘The risk of cancer is therefore very low if the MRI scan of the prostate shows no abnormalities,’ summarises Charlie Hamm. ‘Although an inconspicuous MRI finding alone does not offer 100 per cent certainty, if patients are checked regularly, possible cancer can be detected early enough. For many men, this means they can avoid the unpleasant tissue sample for the time being and still not have to worry about cancer being overlooked.’
Check-ups are sufficient to detect cancer at an early stage
For the study, the team examined almost 600 men with suspected prostate cancer. A so-called multiparametric MRI (mpMRI) – also known as MR prostatography – was carried out on them at the Charité. This MRI combines several tissue-specific parameters, such as the signal intensity of the prostate tissue, blood flow and the diffusion of water molecules in the tissue. A team of experienced radiologists analysed the images. ‘A tissue sample was only taken if the MRI images showed suspicious changes in the prostate. The men with unremarkable MRI findings underwent regular urological check-ups for three years instead. This allowed us to see whether this approach was safe,’ says Charlie Hamm, describing the procedure.
High-quality MRI findings and safety net are essential
The study has now been completed after eight years. ‘The results are an important step towards personalised prostate cancer care. By using magnetic resonance imaging more effectively, we can ensure that men receive the right examinations and treatments at the right time,’ says the doctor and fellow of the Junior Clinician Scientist Programme, which Charité runs together with the Berlin Institute of Health at Charité (BIH).
The results are also relevant for doctors to help their patients decide when a biopsy is really necessary. The European Society of Urology already recommends an MRI before a prostate biopsy in its guidelines. However, it was previously unclear how safe it is to completely forgo a biopsy in the event of a negative MRI result. ‘Our results now show that the so-called MRI diagnostic route is safe and effective even in a decentralised, outpatient care network,’ says Charlie Hamm. ‘We hope that the study will provide an impetus to further strengthen the importance of MRI as a decision-making aid for or against a biopsy in the German guideline.’
However, according to the study authors, two further aspects are crucial if the new findings are to find their way into practice in the near future: firstly, the MRI images must be performed and analysed by experienced specialists. This means training more radiologists in the accurate interpretation of prostate MRI images and applying standardised procedures. Secondly, it is important to create a safety net for men who do not initially receive a biopsy. ‘This means clear guidelines for PSA monitoring, repeated MRI examinations and criteria for when a biopsy might be necessary later,’ emphasises Charlie Hamm.
*Hamm CA. et al. Oncological Safety of MRI-Informed Decision-Making in Men With Suspected Prostate Cancer. 2024 JAMA Oncol. Dec 12 doi: 101001/jamaoncol.2024.5497
About the Study
The study was conducted in close cooperation between urology practices in Berlin and the Charité Department of Radiology. The doctors in private practice were involved in the design of the study as well as in the recruitment, follow-up examinations and treatments. The study was funded by the Berliner Krebsgesellschaft e.V., the Berliner Röntgengesellschaft – Röntgenvereinigung zu Berlin und Brandenburg e.V. and the Berliner Urologische Gesellschaft e.V., among others.