In an international first, a clinical trial at Brisbane’s Wesley Hospital has shown that a medical resonance imaging (MRI)-guided technique will significantly improve diagnosis of life-threatening prostate cancer while reducing over-diagnosis of non-life-threatening cases.
Wesley urologist Dr Les Thompson today detailed key findings of a two-year study published in the journal European Urology. The study found that use of multi-parametric MRI (mpMRI):
• Reduced the number of men needing prostate biopsies by 51%
• Reduced the problem of over-diagnosis of non-life threatening disease by about 90%
• Had a 92% sensitivity in diagnosing life-threatening prostate cancer. (Compared with the current leading method for prostate cancer diagnosis - transrectal ultrasound biopsy – which had a 70% sensitivity in diagnosing life-threatening prostate cancer).
"This latest mpMRI imaging technique will reduce over-treatment of men with non-life-threatening prostate cancer, avoiding the possible side-effects of treatment,” Dr Thompson said.
"This is a significant improvement in terms of accuracy and in reducing discomfort for patients and spares many men the burden of multiple prostate biopsies.”
The clinical trial was conducted by Dr Thompson in collaboration with Dr Rob Parkinson, a specialist radiologist from Wesley Medical Imaging, Professor Jelle Barentsz, from the Radboud University Nijmegen Medical Center, The Netherlands and Dr Morgan Pokorny, a Research Urological Fellow at Queensland University of Technology. The trial was supported by the Wesley Research Institute and the Thoresen Foundation.
In the study, 223 patients who had elevated prostate-specific antigen (PSA) levels underwent two different diagnostic approaches: a standard transrectal ultrasound biopsy (TRUSGB) and mpMRI imaging of their prostates. Only those patients whose MRI images pointed to high-risk prostate cancer then underwent mpMRI-guided biopsy to pinpoint cancer.
TRUSGB had a 70% sensitivity in diagnosing life-threatening prostate cancer while mpMRI had a 92% sensitivity in diagnosing life-threatening prostate cancer.
“TRUSGB uses as many as 12 to 30 needles for biopsy to randomly test cells in the prostate,” Dr Thompson said. “The mpMRI-guided biopsy needs only two needles directed into the suspicious area that has been identified on the mpMRI images.”
Wesley Medical Imaging radiologist Dr Parkinson said that mpMRI used three parameters when imaging the prostate.
“Diffusion-weighted imaging, one of these three parameters, assesses movement of water molecules within tissues. An imaging map is mathematically generated from this information, and prostate cancer is evident as a dark area,” Dr Parkinson said.
“When biopsies are done under ultrasound guidance, random core samples are obtained from all areas of the prostate.
“When biopsies are performed after a prostate mpMRI, you know where the tumour is located and thus where to direct the biopsy needle.”