OBJECTIVE: To determine whether multiparametric magnetic resonance imaging (mp-MRI) has a role in reducing the uncertainty in risk stratification by transrectal ultrasound (TRUS) biopsy, using histology at transperineal template-guided prostate mapping (TPM) biopsy as the reference test.
MATERIALS AND METHODS: Overall, 194 patients underwent TRUS biopsy, who were followed up in less than 18 months by means of (a) mp-MRI with pelvic phased array using T2-weighted, diffusion-weighted and dynamic contrast-enhanced sequences and (b) TPM biopsy. Of those patients, low risk on TRUS biopsy was defined in 4 different ways-(a) definition 1: Gleason 3+3 (any cancer core length) (n = 137), (b) definition 2: maximum cancer core length (MCCL)< 50% (any Gleason score) (n = 62), (c) definition 3: Gleason 3+3 and MCCL< 50% (n = 52), and (d) definition 4: Gleason 3+3, MCCL< 50%, prostate-specific antigen level< 10ng/ml, and< 50% positive cores (n = 28). Mp-MRI was scored for the likelihood of cancer from 1 (cancer very unlikely) to 5 (cancer very likely). Binary logistic regression analysis was performed to evaluate the association between MRI scores and TPM histology.
RESULTS: Median prostate-specific antigen level was 7ng/ml (range: 0.9-29), median time between TRUS biopsy and mp-MRI was 120 days (range: 41-480), and median time between mp-MRI and TPM biopsy was 60 days (range: 1-420). A median of 48 cores (range: 20-118) were taken at TPM biopsy. Gleason score was upgraded in 62 of 137 (45%) patients at TPM biopsy. The negative predictive values of mp-MRI score 1 to 2 for predicting that cancer remained low risk (according to each definition) were 75%, 100%, 83%, and 100% for definitions 1, 2, 3, and 4, respectively. An mp-MRI score of 4 to 5 had positive predictive values for upgrade or upsize of 59%, 67%, 75%, and 69% for definitions 1, 2, 3, and 4, respectively.
CONCLUSION: The presence of an mp-MRI lesion in men with low-risk prostate cancer on TRUS biopsy confers, in most patients, a high likelihood that higher-risk disease will be present (either Gleason pattern 4 or a significant cancer burden). Conversely, if a lesion is not seen on mp-MRI, the attribution of low-risk grade or cancer burden is much more likely to be correct. Mp-MRI might therefore be used to triage men for resampling biopsies before entering active surveillance.
Written by:
Abd-Alazeez M, Ahmed HU, Arya M, Allen C, Dikaios N, Freeman A, Emberton M, Kirkham A. Are you the author?
Department of Urology, University College London Hospital NHS Foundation Trust, London, UK; Department of Urology, Faculty of medicine, Fayoum University, Fayoum, Egypt; Division of Surgery and Interventional Science, University College London, London, UK; Department of Urology, University College London Hospital NHS Foundation Trust, London, UK; Barts Cancer Institute, Queen Mary University of London, London, UK; Department of Radiology, University College London Hospital NHS Foundation Trust, London, UK; Centre for Medical Imaging, University College London, London, UK; Department of Histopathology, University College London Hospitals NHS Foundation Trust, London, UK.
Reference: Urol Oncol. 2014 Aug;32(6):741-7.
doi: 10.1016/j.urolonc.2014.01.008
PubMed Abstract
PMID: 24981993
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