Detection of significant prostate cancer with magnetic resonance targeted biopsies--should transrectal ultrasound-magnetic resonance imaging fusion guided biopsies alone be a standard of care?

PURPOSE: Magnetic resonance imaging-transrectal ultrasound fusion targeted prostate biopsies were suggested to detect significant cancer with more accuracy than systematic biopsies. In this study we evaluate the pathological characteristics of multiparametric magnetic resonance imaging detected and undetected tumor foci on radical prostatectomy specimens. MATERIALS AND METHODS: We selected 125 consecutive patients treated with radical prostatectomy for clinically localized prostate cancer diagnosed on magnetic resonance imaging-transrectal ultrasound targeted biopsy and/or systematic biopsy. On multiparametric magnetic resonance imaging each suspicious area was graded according to the PI-RADS score. On radical prostatectomy specimen, tumor foci with a Gleason score greater than 3+3 and/or tumor volume greater than 0.5 ml were considered significant. A correlation analysis between multiparametric magnetic resonance imaging and pathological findings was performed. RESULTS: Pathological analysis of radical prostatectomy specimens detected 230 tumor foci. Of these, 137 were considered significant (Gleason score greater than 3+3 in 112) and were observed in 111 (89%) glands. A total of 95 individual tumor foci, including 14 significant foci, were missed with multiparametric magnetic resonance imaging. All of them were located in glands where another focus was detected with multiparametric magnetic resonance imaging. An additional 9 individual tumor foci, including 7 significant, were detected on multiparametric magnetic resonance imaging but missed with targeted biopsy, resulting in 5 (4%) significant cancers undetected with magnetic resonance imaging-transrectal ultrasound fusion targeted biopsy. The magnetic resonance imaging target largest diameter was associated with high volume (greater than 0.5 cc) foci detection, while PI-RADS score and cancer involvement on targeted biopsy were associated with significant foci detection. CONCLUSIONS: In these series of men with suspicious prostate multiparametric magnetic resonance imaging findings, magnetic resonance imaging-transrectal ultrasound fusion guided targeted biopsy alone strategy would have resulted in the under detection of only 4% significant cancers.

Prebiopsy magnetic resonance imaging and prostate cancer detection: comparison of random and targeted biopsies.

PURPOSE: We compared the accuracy of visual targeted biopsies vs computerized transrectal ultrasound-magnetic resonance imaging registration using a rigid (Esaote®, nondeformable) or elastic (Koelis®, deformable) approach. MATERIALS AND METHODS: A total of 391 consecutive patients with suspected localized prostate cancer were prospectively included in analysis. All patients underwent prostate magnetic resonance imaging, followed by 10 to 12-core random prostate biopsies. When magnetic resonance imaging detected suspicious findings, targeted biopsy was performed, including visual, rigid system and elastic system targeted biopsies in the first 127 patients, the next 131 and the last 133, respectively. Cancer detection rates were assessed by conditional logistic regression. Targeted biopsies alone and random biopsies were further compared for the amount of tissue sampled and microfocal cancer detection, the latter defined as a single core with 5 mm or less of Gleason 6 cancer. RESULTS: Patient characteristics and random biopsy detection rates were similar among the groups. Magnetic resonance imaging detected at least 1 suspicious area in 54 (42%), 78 (59%) and 82 patients (62%) in groups 1, 2 and 3, respectively. The cancer detection rates of rigid and elastic system targeted biopsies were significantly higher than the random biopsy rate (p = 0.0065 and 0.0016, respectively). Visual targeted biopsy did not perform better than random biopsy (p = 0.66). Rigid and elastic system targeted biopsies allowed for decreasing the number of cores and the detection of microfocal cancer, while increasing the detection of high grade cancer. CONCLUSIONS: When performed with computerized magnetic resonance imaging-transrectal ultrasound image registration, targeted biopsy alone improved cancer detection over random biopsies, decreased the detection rate of microfocal cancer and increased the detection rate of cancer with a Gleason score of greater than 6.