We have carried out MRI scans before biopsy for the past four years. Now a major study shows this is twice as effective in identifying prostate cancer and should be adopted as standard practice in the UK

Mr Alan Doherty

By Alan Doherty, consultant urologist, BPC

It has been hailed as a game changer which is the biggest leap forward in prostate cancer diagnosis for decades. Such is the significance of the major trial, published today in The Lancet ,  which shows a multi-parametric MRI scan is twice as accurate in prostate cancer detection, compared with a traditional TRUS biopsy.

The trial, called the PROMIS study, involved 576 men with suspected prostate cancer, who were allocated either a standard TRUS biopsy (trans-rectal ultrasound guided) or a multi-parametric MRI scan.

The findings from these two types of assessments was then compared with a benchmark template biopsy to see how accurate the results of both assessment methods were in identifying prostate cancer.

The ‘headline’ results are emphatic:

  • The MRI identified up 93 per cent of aggressive cancers, compared with 48 per cent for the TRUS biopsy
  • Up to a quarter of men who have a MRI scan before biopsy could avoid proceeding to biopsy because the MRI accurately indicates this is not necessary
  • 11 per cent of harmful prostate cancers were missed using mpMRI, whereas 26 per cent were missed using a TRUS biopsy alone.

As such, the chief executive of the Prostate Cancer Charity, Angela Culhane, was unequivocal in describing the study as a game changer which must drive a wholescale transformation in the way prostate cancer is assessed.

When we first introduced multi-parametric MRI at BPC six years ago, the quality of the information they produced was immediately evident. Multi-parametric means an MRI process which combines three different types of scan and uses a contrast agent to enhance three different images. We recognised the importance of mpMRI particularly when prostate cancer is present in the anterior lobe (one in four prostate cancers), in assessing risk and therefore making the decision about next steps.

It was also evident that if we carried out a biopsy then an MRI, the biopsy traumatised the prostate tissue and could compromise the quality of the images from the MRI. It was logical to change our diagnostic pathway to MRI before biopsy and doing so four years ago, we were recognised as one of the first to make this change.

We have also always believed in the need to constantly review, assess and beware of any assessment or treatment which is hailed as ‘the solution’ to the imperfect science of assessing prostate cancer.

So while the PROMIS study attests to the quality of mpMRI, as a patient, the finding that mpMRI only missed 11 per cent of harmful cancers, compared with 26 missed using TRUS biopsy would not fully reassure me.

For this reason, at BPC our standard pathway also includes the PCA3 test,which we have also been using for six years as it has a proven record of predicting prostate cancer risk. The PCA3 result works very well with the mpMRI, together with the PSA result and findings from the physical examo.uination.

I need to feel very reassured by all four measures before I tell a patient we do not need to proceed to biopsy. Equally, with those four measures, I can feel confident moving to biopsy because I know that I am doing so with solid evidence.

I very rarely use a TRUS biopsy because it does not give me sufficient assurance. The trans-rectal biopsy is a simpler procedure, needing only a local anaesthetic and not requiring theatre time, but it is notoriously inaccurate. Using 12 needles to take tissue samples from a whole gland is something I would only do if I have particularly clear evidence of a single lesion and high confidence in its location.

For the vast majority of our patients, we use a template biopsy method, as they did in the PROMIS study, to provide a much higher degree of assurance and accuracy. The template is based on using a larger number of tissue samples (can be about 24 but depends on individual) and mapping techniques mean that the space between tissue samples throughout the whole gland is only 5 millimeters, thus the risk of missing cancer is much reduced.

In conclusion, I welcome the PROMIS study as a very significant important step for much needed improvements in assessing prostate cancer, firmly challenging any assessment pathway based on the notoriously ‘blunt tools’ of raised PSA leading to a TRUS biopsy.

FIND OUT MORE

» The distinctive way we assess and diagnose prostate cancer at The Birmingham Prostate Clinic

» Our prostate cancer pathway, step-by-step

» Why we support MRI before biopsy

» Our patients describe their treatment at Birmingham Prostate Clinic

» See our consultants in television documentaries and discussing our approach to prostate cancer treatment and diagnosis