Prostate cancer is a big worry for many men as they get older, and when urinary symptoms start, it is best to get checked out by a doctor, even if just to be on the safe side. There are a number of different tests and scans to check for signs of prostate cancer. Multi-parametric MRI (mpMRI) scans are an advanced form of MRI scanning which produces more detailed images than standard MRIs. Leading urologist Professor Richard Hindley explains how mpMRIs are changing how we look for prostate cancer.
What are the benefits of mpMRI scanning for prostate cancer diagnosis?
The benefits of a multi-parametric MRI for prostate cancer diagnosis are very significant thanks to a trial called the PROMIS Trial, which was run by the MRC (Medical Research Council) in London. We are now routinely offering men the opportunity to have an MRI of their prostate gland if we suspect that there is a possibility of prostate cancer. That would either be due to the PSA blood test reading being elevated or the recent development of urinary symptoms or the prostate gland feeling abnormal or worrying after an examination.
This will allow close to 40% of men to avoid the need for a biopsy, because if the MRI is normal, we can then reassure the patient, and avoid the need for potentially harmful biopsies. Furthermore, if the MRI highlights an area or areas within the prostate gland where there is something suspicious, then we can target our biopsies on those areas or lesions within the prostate gland so that we can get a more accurate diagnosis.
What happens following an mpMRI scan?
After an MRI scan, you will normally be reviewed by a urologist and have a discussion about the result of the MRI scan. If it's normal, then it is likely that you could be discharged back to your GP or be reviewed perhaps in six months or a year with another PSA blood test.
If the MRI has shown an area or some areas of concern, then it's likely that you would then need to have some targeted biopsies of these areas. Sometimes there can be a scan which is equivocal, meaning that we're not sure whether there's anything to worry about or not, and that would be down to the urologist to discuss with you how best to manage things moving forward. Some of those men will require biopsies and others can be safely monitored.
How do mpMRI scanning and template biopsies improve the accuracy of diagnosis?
Essentially, having an MRI to look at when one is proceeding with biopsies enables you to be more accurate in targeting any areas of concern within the prostate gland. The best way to do that is by the transperineal approach, which means going through the perineum (the bit between the legs that we sit on when we ride a bike).
We target any areas of concern that have been highlighted on the MRI and we can use special fusion software to do that, because when we're actually taking the biopsies we have to use ultrasound; we can't currently biopsy somebody in an MRI scanner. We use those MRI scan images though and upload them into the cloud and then marry them up with the ultrasound pictures that we have in real time when we're doing the biopsies. That enables us to hit the centre or close to the centre of any significant areas of possible prostate cancer, which is usually where the most aggressive component of that cancer is.
In this way, we’re better able to identify if there is cancer there, and determine whether treatment is required (some prostate cancers can be monitored). Although it's too soon for this to translate into an improvement in outcomes, it's almost certain that this is going to happen over the next decade as more men come through this new, improved pathway, which involves having an MRI scan at the start rather than having the traditional hit-and-miss transrectal biopsies, which are very unreliable and come with a risk of significant infection.