The finding could lead to fewer men having biospies they do not need.
PSA is a protein found in the blood that can be used to help diagnose prostate cancer. But not all men with raised PSA have prostate cancer.
Men with raised PSA are usually advised to have ultrasound-guided biopsy (TRUS), where a needle is inserted into the prostate multiple times to remove tissue for subsequent analysis.
But many men undergoing a biopsy will not have prostate cancer, and occasionally these biopsies can miss cancers or underestimate how serious they are.
The PROMIS study involved 576 men in 11 UK hospitals who had an elevated PSA and no prior biopsy.
They were first given an MRI scan, then a combination of two forms of biospy – a ‘standard’ TRUS biopsy, which takes 10-15 samples, and a more accurate but more-invasive form called a TPM-biopsy, which can take up to 50 samples.
Comparing the results of all the tests, the research team calculated that using MRI before a TRUS biospy could help avoid a primary biopsy in 27 per cent of men.
Professor Malcolm Mason, Cancer Research UK’s prostate cancer expert, said: “These results confirm the potential benefit of using MRI scans to help diagnose prostate cancer. It’s now up to NICE to assess this approach for use by the NHS.
“If it were introduced it would reduce the number of men having unnecessary biopsies. But to ensure it was robust, there would need to be consistent standards for the MRI imaging technique, equipment and analysis.”
Under current NHS guidelines, patients with suspected prostate cancer are not routinely offered an MRI due to its high cost.
Ahmed, H. et. al. (2016) The PROMIS study: A paired-cohort, blinded confirmatory study evaluating the accuracy of multi-parametric MRI and TRUS biopsy in men with an elevated PSA. J Clin Oncol 34 (suppl; abstr 5000)