'25 at 25': Improving prostate cancer diagnosis
13 Nov 2024
As part of our ‘25 at 25’ series, highlighting 25 achievements of the MRC Clinical Trials Unit at UCL from the last 25 years, we look at how the PROMIS study has improved how prostate cancer is diagnosed, sparing thousands of men unnecessary biopsies.
Prostate cancer is the most common cancer among men in the UK. Every year many thousands of men have a transrectal-ultrasound (TRUS) biopsy to see if they have the disease, but there are problems with this approach. Before the PROMIS study, it was suspected that TRUS biopsies were not very good at detecting cancer and may have been missing clinically important cases. This meant that men were often required to have extra tests if the biopsy did not find signs of cancer. The biopsies are uncomfortable for patients, and have risks, including infections, pain, blood in urine or sperm and pain while urinating.
PROMIS tested whether an MP-MRI (multi-parametric magnetic resonance imaging) scan before biopsy could identify men who might safely avoid a biopsy. PROMIS compared the accuracy of both MP-MRI and TRUS-biopsy against another, more accurate but more invasive type of biopsy, called Template Prostate Mapping (TPM) biopsy. It is not practical for TPM biopsies to be given to everyone in standard of care, but they are the most accurate way of determining whether there is any cancer in the prostate.
Between May 2012 and December 2015, 740 men volunteered for the trial of whom 576 had all three tests - an MP-MRI scan, followed (under general anaesthetic) by a combined TPM-biopsy and TRUS-biopsy. Patients and clinicians were not aware of the results of the other tests until all tests had been completed and reported independently.
PROMIS found that an MP-MRI scan before biopsy would allow at least one in four men to safely avoid a biopsy. This was because the chance that men with a negative MP-MRI had clinically important prostate cancer was very low. The MP-MRI scan identified more than 90% of patients who had clinically important cancer, compared to TRUS biopsies which only identified 48% of the men who had clinically important cancer.
Men whose MP-MRI scan suggest they may have prostate cancer still need to have a biopsy, but the scan results may help improve the accuracy of the biopsy by showing doctors which part of the prostate to target. This is called MRI-targeted biopsy.
The PROMIS team worked with Prostate Cancer UK to help develop training and other tools to help clinicians implement the approach safely and effectively. This includes a series of short films about the trial and its results.
In 2019, the National Institute of Health and Care Excellence updated their guidance, based on the PROMIS results, to recommend that MP-MRI is used prior to biopsy for people with suspected prostate cancer. The European Association of Urology and American Urology Association also updated their guidelines to recommend pre-biopsy MRI.
PROMIS was coordinated by the MRC CTU at UCL, and took place in 11 hospitals in the UK. PROMIS was funded by the NIHR Health Technology Assessment programme (project number 09/22/67). The views and opinions expressed therein and in any media associated with this study are those of the authors and do not necessarily reflect those of the HTA programme, NIHR, NHS or the Department of Health.
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