Prostate biopsy targeted to suspicious lesions on multiparametric magnetic resonance imaging has encouraging rates of detection of clinically significant cancer while also decreasing the detection rate of clinically insignificant cancer. This is achieved with fewer biopsy cores than for systematic template guided biopsy. Further prospective, multicenter, comparative trials of the performance of targeting strategies are needed to consider magnetic resonance imaging targeted biopsy an alternative to conventional systematic biopsy.
Background
Multi-parametric MRI (mp-MRI) has the potential to serve as a non-invasive triage test for men at risk of prostate cancer. Our objective was to determine the performance characteristics of multi-parametric MRI (mpMRI) in men at risk prior to first biopsy using 5mm template prostate mapping (TPM) as the reference standard.
Methods
One hundred and twenty nine consecutive men with clinical suspicion of prostate cancer that had no prior biopsy, underwent mpMRI (T1/T2-weighted, diffusion-weighting, dynamic-contrast enhancement) followed by TPM. The primary analysis used: a) radiological scores of suspicion of ≥3 attributed from a 5-point ordinal scale, b) a target condition on TPM of any Gleason pattern ≥4 and/or a maximum cancer core length of ≥4mm and c) two sectors of analysis per prostate (right and left prostate halves). Secondary analyses evaluated the impact of: a) changing the mpMRI score threshold to ≥4 and b) varying the target definition for clinical significance.
Results
141/258 (55%) sectors of analysis showed “Any cancer”; 77/258 (30%) had the target histological condition for the purpose of deriving the primary outcome. Median (with range) for age, PSA, gland volume and number of biopsies taken were 62 years (−41-82), 5.8ng/ml (1.2-20), 40ml (16-137) and 41 cores (20-93). For the primary outcome sensitivity, specificity, positive and negative predictive values and area under the receiver operating curve (with 95% CI) were 94% (88-99%), 23% (17-29%), 34% (28-40%), 89% (79-98%) and 0.72 (0.65-0.79), respectively.
Conclusion
MpMRI demonstrated encouraging diagnostic performance characteristics in detecting and ruling-out clinically significant prostate cancer in men at risk who were biopsy naive.
PurposeTo assess the performance of multiparametric magnetic resonance imaging (mp-MRI) in patients with previous negative transrectal ultrasound (TRUS) guided prostate biopsy.Materials and methodsFifty-four patients with at least 1 previous negative TRUS prostate biopsy underwent mp-MRI in the form of T2-weighted, diffusion-weighted, and dynamic contrast-enhanced imaging. This was followed by transperineal template systematic prostate biopsies. Analysis was done based on 2 sectors per prostate, right and left (108 sectors out of 54 prostates). mp-MRI was scored using an ordinal scale 1 to 5 based on the suspicion of the presence of clinically significant disease. We used 6 different definitions for clinically significant disease and tested the performance of mp-MRI at each single definition.ResultsMedian age was 64 (range, 39–75), median PSA level was 10 (range, 2–23), and median number of biopsies was 45 (range, 21–137). Cancer of any volume and any grade was detected in 34 of 54 (63%) patients. mp-MRI accuracy at detection of clinically significant cancer using University College London (UCL) definition 2 (any Gleason score of 4 or maximum cancer core length of ≥4 mm or both) showed sensitivity of 76%, specificity of 42%, positive predictive value of 38%, and negative predictive value of 79%. For a different definition of significant tumor (UCL definition 1; dominant Gleason score 4 or maximum cancer core length ≥6 mm or both), the sensitivity was 90%, specificity 42%, positive predictive value 26%, and negative predictive value 95%.Conclusionsmp-MRI showed good performance at both detection and ruling out clinically significant disease, according to the definition used. mp-MRI can then be used as a triage test in the population with persistently elevated or rising PSA levels to select patients that can avoid unnecessary prostate biopsy.
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