Theresa Renner

Direct comparison of multiparametric magnetic resonance imaging (MRI) results with final histopathology in patients with proven prostate cancer in MRI/ultrasonography‐fusion biopsy

To compare multiparametric magnetic resonance imaging (mpMRI) of the prostate and histological findings of both targeted MRI/ultrasonography‐fusion prostate biopsy (PBx) and systematic PBx with final histology of the radical prostatectomy (RP) specimen.

Prospective comparison of transperineal magnetic resonance imaging/ultrasonography fusion biopsy and transrectal systematic biopsy in biopsy-naïve patients

To evaluate the value of multiparametric magnetic resonance imaging (mpMRI) in the detection of significant prostate cancer (PCa) and to compare transperineal MRI/ultrasonography fusion biopsy (fusPbx) with conventional transrectal systematic biopsy (sysPbx) in biopsy‐naïve patients.

Evaluation of Prostate Imaging Reporting and Data System Classification in the Prediction of Tumor Aggressiveness in Targeted Magnetic Resonance Imaging/Ultrasound-Fusion Biopsy

Objectives: The study aimed to evaluate the prediction of Prostate Imaging Reporting and Data System (PI-RADS) with respect to the prostate cancer (PCa) detection rate and tumor aggressiveness in magnetic resonance imaging (MRI)/ultrasound-fusion-biopsy (fusPbx) and in systematic biopsy (sysPbx). Materials and Methods: Six hundred and twenty five patients undergoing multiparametric MRI were investigated. MRI findings were classified using PI-RADS v1 or v2. All patients underwent fusPbx combined with sysPbx (comPbx). The lesion with the highest PI-RADS was defined as maximum PI-RADS (maxPI-RADS). Gleason Score ≥7 (3 + 4) was defined as significant PCa. Results: The overall PCa detection rate was 51% (n = 321; 39% significant PCa). The detection rate was 43% in fusPbx (n = 267; 34% significant PCa) and 36% in sysPbx (n = 223; 27% significant PCa). Nine percentage of significant PCa were detected by sysPbx alone. A total of 1,162 lesions were investigated. The detection rate of significant PCa in lesions with PI-RADS 2, 3, 4, and 5 were 9% (18/206), 12% (56/450), 27% (98/358), and 61% (90/148) respectively. maxPI-RADS ≥4 was the strongest predictor for the detection of significant PCa in comPbx (OR 2.77; 95% CI 1.81-4.24; p < 0.005). Conclusions: maxPI-RADS is the strongest predictor for the detection of significant PCa in comPbx. Due to a high detection rate of additional significant PCa in sysPbx, fusPbx should still be combined with sysPbx.

Evaluation of Magnetic Resonance Imaging/Ultrasound-Fusion Biopsy in Patients with Low-Risk Prostate Cancer Under Active Surveillance Undergoing Surveillance Biopsy

Introduction: Targeted biopsy of tumour-suspicious lesions detected in multiparametric magnetic resonance imaging (mpMRI) plays an increasing role in the active surveillance (AS) of patients with low-risk prostate cancer (PCa). The aim of this study was to compare MRI/ultrasound-fusion biopsy (fusPbx) with systematic biopsy (sysPbx) in patients undergoing biopsy for AS. Methods: Patients undergoing mpMRI and transperineal fusPbx combined with transrectal sysPbx (comPbx) as surveillance biopsy were investigated. The detection of Gleason score upgrading and reclassification according to Prostate Cancer Research International Active Surveillance criteria were evaluated. Results: Eighty-three patients were enrolled. PCa upgrading was detected in 39% by fusPbx and in 37% by sysPbx (p = 1.0). The percentage of patients who were reclassified in fusPbx and sysPbx (p = 0.45) were 64 and 59% respectively. ComPbx detected more frequently tumour upgrading than fusPbx (71 vs. 64%, p = 0.016) and sysPbx (71 vs. 59%, p < 0.001) and more patients had to be reclassified after comPbx than after fusPbx or sysPbx alone. Conclusions: The combination of fusPbx and sysPbx outperforms both modalities alone with regard to the detection of upgrading and reclassification in patients under AS. Because a high missing rate of significant PCa still exists in both biopsy modalities, a combination of fusPbx and sysPbx should be recommended in these patients.

Evaluation of Transperineal Magnetic Resonance Imaging/Ultrasound-Fusion Biopsy Compared to Transrectal Systematic Biopsy in the Prediction of Tumour Aggressiveness in Patients with Previously Negative Biopsy

Objectives: We compared the transperineal MRI/ultrasound-fusion biopsy (fusPbx) to transrectal systematic biopsy (sysPbx) in patients with previously negative biopsy and investigated the prediction of tumour aggressiveness with regard to radical prostatectomy (RP) specimen. Material and Methods: A total of 710 patients underwent multiparametric magnetic resonance imaging (mpMRI), which was evaluated in accordance with Prostate Imaging Reporting and Data System (PI-RADS). The maximum PI-RADS (maxPI-RADS) was defined as the highest PI-RADS of all lesions detected in mpMRI. In case of proven prostate cancer (PCa) and performed RP, tumour grading of the biopsy specimen was compared to that of the RP. Significant PCa (csPCa) was defined according to Epstein criteria. Results: Overall, scPCa was detected in 40% of patients. The detection rate of scPCa was 33% for fusPbx and 25% for sysPbx alone (p < 0.005). Patients with a maxPI-RADS ≥3 and a prostate specific antigen (PSA)-density ≥0.2 ng/mL2 harboured more csPCa than those with a PSA-density < 0.2 ng/mL2 (41% [33/81] vs. 20% [48/248]; p < 0.001). Compared to the RP specimen (n = 140), the concordance of tumour grading was 48% (γ = 0.57), 36% (γ = 0.31) and 54% (γ = 0.6) in fusPbx, sysPbx and comPbx, respectively. Conclusions: The combination of fusPbx and sysPbx outperforms both biopsy modalities in patients with re-biopsy. Additionally, the PSA-density may represent a predictor for csPCa in patients with maxPI-RADS ≥3.

PD43-01 ASSESSMENT OF TUMOUR-AGGRESSIVENESS IN TRANSPERINEAL MRI/ULTRASOUND-FUSION BIOPSY IN COMPARISON TO TRANSRECTAL SYSTEMATIC PROSTATE BIOPSY IN PATIENTS WITH AND WITHOUT PRIOR BIOPSY

INTRODUCTION AND OBJECTIVES: To address limitations of current commercial, mass-produced robot-assisted surgical systems widely used in urology and other surgical specialties, we propose to develop patientand procedure-specific dexterous robots. Our focus is on a class of continuum robots known as concentric tube robots, which are comprised of a series of hollow, nesting, precurved tubes that are individually inserted and rotated with respect to one another in order to change the shape of the overall robot. We aim to develop a method for designing, fabricating, and driving a patient-specific concentric tube robot as an alternative paradigm to traditional robotic surgical systems in order to improve procedures for specialized patient groups. As a test case we focus here on nonlinear renal access, for example, subcostal punctures into the upper pole calyces of the kidney to ablate an endophytic renal mass. METHODS: To enable patient-specific design of these robots, a virtual-reality based interface was developed. The interface leverages the expertise of a surgeon by immersing him or her in a 3-D virtual environment that includes a reconstructed model of the patient’s thoracoabdominal anatomy based on CT scans. Once the surgeon designs the set of concentric tubes, we generate a 3-D model and subsequently 3-D print each tube using a biocompatible polycaprolactone (PCL) filament. The printed tubes are then nested one inside the next and attached to the compact, modular actuation and control system we built for driving these robots. The surgeon controls the movement of the concentric tube robot through a teleoperation control scheme. RESULTS: A board-certified urologist performed a preliminary test of the entire system. After an explanation of the interface and its features, the surgeon was immersed in the virtual environment (using 3D reconstructions of an actual patient’s upper abdominal anatomy, including kidney and an associated upper caliceal lesion) and tasked with designing a set of tubes to access the lesion. Based on his intuition and expertise, he designed three different sets, which were then 3-D printed with PCL. The surgeon then performed mock procedures by driving each concentric tube robot into a phantom model of the patient’s thoracoabdominal anatomy in order to reach the lesion. The lesion was generated using a thermochromic dye which changes color when heated. Once the target was reached, a radiofrequency ablation (RFA) probe was passed through the concentric tube robot and successful ablation confirmed by color change of the lesion. CONCLUSIONS: This work proposes a framework for integration of the surgeon into design and fabrication of a set of patientand procedurespecific concentric tubes. Preliminary results demonstrate that a surgeon can use the interface to design a concentric tube robot to access and ablate renal lesions by RFA.