Objectives: The purpose of this study was to investigate the detection rate of prostate cancer (PCa) by multiparametric magnetic resonance imaging-targeted biopsies (mp-MRI-bx) in patients with prior negative transrectal ultrasound biopsy (TRUS-bx) sessions without previous experience of this.
Material and methods: Eighty-three patients with prior negative TRUS-bx scheduled for repeated biopsies due to persistent suspicion of PCa were prospectively enrolled. mp-MRI was performed before biopsy and all lesions were scored according to the Prostate Imaging Reporting and Data System (PI-RADS) and Likert classification. All underwent repeated TRUS-bx (10 cores) and mp-MRI-bx under visual TRUS guidance of any mp-MRI-suspicious lesion not targeted by systematic TRUS-bx.
Results: PCa was found in 39 out of 83 patients (47%) and mp-MRI identified at least one lesion with some degree of suspicion in all 39 patients. Both PI-RADS and Likert scoring showed a high correlation between suspicion of malignancy and biopsy results (p < 0.0001). Five patients (13%) had cancer detected only on mp-MRI-bx outside the TRUS-bx areas (p = 0.025) and another seven patients (21%) had an overall Gleason score upgrade of at least one grade based on the mp-MRI-bx. Secondary PCa lesions not visible on mp-MRI were detected by TRUS-bx in six out of 39 PCa patients. The secondary foci were all Gleason 6 (3 + 3) in 5-10% of the biopsy core. According to the Epstein criteria, 37 out of 39 cancer patients were classified as clinically significant.
Conclusion: Using mp-MRI, even without previous experience, can improve the detection rate of significant PCa at repeated biopsy and allows more accurate Gleason grading.
Keywords: multiparametric MRI; prostate biopsy; prostate cancer; targeted biopsy; transrectal ultrasound; visual fusion.