What the urologist needs to know before radical prostatectomy: MRI effective support to pre-surgery planning

BACKGROUND

Radical prostatectomy (RP) is recommended in case of localized or locally advanced prostate cancer (PCa), but it can lead to side effects, including urinary incontinence (UI) and erectile dysfunction (ED). Magnetic resonance imaging (MRI) is recommended for PCa diagnosis and staging, but it can also improve preoperative risk-stratification.

PURPOSE

This nonsystematic review aims to provide an overview on factors involved in RP side effects, highlighting anatomical and pathological aspects that could be included in a structured report.

EVIDENCE SYNTHESIS

Considering UI evaluation, MR can investigate membranous urethra length (MUL), prostate volume, the urethral sphincter complex, and the presence of prostate median lobe. Longer MUL measurement based on MRI is linked to a higher likelihood of achieving continence restoration. For ED assessment, MRI and diffusion tensor imaging identify the neurovascular bundle and they can aid in surgery planning. Finally, MRI can precisely describe extra-prostatic extension, prostate apex characteristics and lymph-node involvement, providing valuable preoperative information for PCa treatment.

CONCLUSIONS

Anatomical principals structures involved in RP side effects can be assessed with MR. A standardized MR report detailing these structures could assist urologists in planning optimal and tailored surgical techniques, reducing complications, and improving patients' care.

Indications for nerve-sparing surgery for radical prostatectomy: Results from a single-center study

Purpose

To explore the clinical indications of using the nerve-sparing technique in radical prostatectomy.

Patients and methods

We retrospectively analyzed the clinical and pathological data of 101 patients who underwent radical prostatectomy (RP) at our institution. Twenty-five patients underwent open surgery, and 76 patients underwent laparoscopic surgery. The biochemical recurrence (BCR) rate was analyzed by the method of Kaplan–Meier. The distance between the ipsilateral neurovascular bundles (NVBs) and foci of prostate tumor (N-T distance) was measured in postoperative specimens. We defined the N-T distance >2 mm as the threshold to perform nerve-sparing (NS) in RP. Through logistic regression analysis, we determined the preoperative clinical indications for the nerve-sparing technique in RP.

Results

The average BCR-free survival time was 53.2 months in these 101 patients with RP, with the 3- and 5-year BCR-free rates being 87.9% and 85.8%, respectively. The N-T distance was measured in 184 prostate sides from postoperative specimens of 101 patients. Univariate analysis showed that the percent of side-specific biopsy cores with cancer (≥1/3), maximum tumor length in biopsy core (≥5 mm), average percent involvement of each positive core (≥50%), PI-RADS score, and prostate MP-MRI imaging (extra-capsular extension) were associated with the N-T distance (p < 0.003). Furthermore, the percent of side-specific biopsy cores with cancer (≥1/3) (OR = 4.11, p = 0.0047) and prostate MP-MRI imaging (extra-capsular extension) (OR = 3.92, p = 0.0061) were found to be statistically significant independent predictors of the N-T distance in multivariate analysis.

Conclusions

The clinical indications of nerve-sparing RP were <1/3 side-specific biopsy cores with cancer and no extra-capsular extension by prostate MP-MRI examination.

Evaluation of the Efficiency of MRI-Based Radiomics Classifiers in the Diagnosis of Prostate Lesions

Objective

To compare the performance of different imaging classifiers in the prospective diagnosis of prostate diseases based on multiparameter MRI.

Methods

A total of 238 patients with pathological outcomes were enrolled from September 2019 to July 2021, including 142 in the training set and 96 in the test set. After the regions of interest were manually segmented, decision tree (DT), Gaussian naive Bayes (GNB), XGBoost, logistic regression, random forest (RF) and support vector machine classifier (SVC) models were established on the training set and tested on the independent test set. The prospective diagnostic performance of each classifier was compared by using the AUC, F1-score and Brier score.

Results

In the patient-based data set, the top three classifiers of combined sequences in terms of the AUC were logistic regression (0.865), RF (0.862), and DT (0.852); RF “was significantly different from the other two classifiers (P =0.022, P =0.005), while logistic regression and DT had no statistical significance (P =0.802). In the lesions-based data set, the top three classifiers of combined sequences in terms of the AUC were RF (0.931), logistic regression (0.922) and GNB (0.922). These three classifiers were significantly different from.

Conclusion

The results of this experiment show that radiomics has a high diagnostic efficiency for prostate lesions. The RF classifier generally performed better overall than the other classifiers in the experiment. The XGBoost and logistic regression models also had high classification value in the lesions-based data set.

The impact of 3D models on positive surgical margins after robot-assisted radical prostatectomy

PURPOSE

To evaluate the role of 3D models on positive surgical margin rate (PSM) rate in patients who underwent robot-assisted radical prostatectomy (RARP) compared to a no-3D control group. Secondarily, we evaluated the postoperative functional and oncological outcomes.

METHODS

Prospective study enrolling patients with localized prostate cancer (PCa) undergoing RARP with mp-MRI-based 3D model reconstruction, displayed in a cognitive or augmented-reality fashion, at our Centre from 01/2016 to 01/2020. A control no-3D group was extracted from the last two years of our Institutional RARP database. PSMr between the two groups was evaluated and multivariable linear regression (MLR) models were applied. Finally, Kaplan-Meier estimator was used to calculate biochemical recurrence at 12 months after the intervention.

RESULTS

160 patients were enrolled in the 3D Group, while 640 were selected for the Control Group. A more conservative NS approach was registered in the 3D Group (full NS 20.6% vs 12.7%; intermediate NS 38.1% vs 38.0%; standard NS 41.2% vs 49.2%; p = 0.02). 3D Group patients had lower PSM rates (25 vs. 35.1%, p = 0.01). At MLR models, the availability of 3D technology (p = 0.005) and the absence of extracapsular extension (ECE, p = 0.004) at mp-MRI were independent predictors of lower PSMr. Moreover, 3D model represented a significant protective factor for PSM in patients with ECE or pT3 disease.

CONCLUSION

The availability of 3D models during the intervention allows to modulate the NS approach, limiting the occurrence of PSM, especially in patients with ECE at mp-MRI or pT3 PCa.

Attitudes and perceptions towards multiparametric magnetic resonance imaging of the prostate: A national survey among Italian urologists

OBJECTIVE

We aimed to assess the attitudes and perceptions towards multiparametric magnetic resonance imaging (mpMRI) of the prostate among Italian urologists.

MATERIAL AND METHODS

A national, web-based survey was performed. A questionnaire composed of 18 multiple choice questions was e-mailed to 941 currently active urologists, members of the Italian Society of Urology. Preserving anonymity, respondents' demographics were collected (e.g. geographic region, type of workplace, prostate procedures performed) as well as data concerning their attitudes and perceptions towards mpMRI (e.g. indications deemed appropriate, degree of confidence in mpMRI results). Data were expressed as raw numbers and percentages of survey answers.

RESULTS

In total, 98 responses were received (participation rate = 10.4%). Respondents mostly worked in urban areas (96%) and primarily in hospital settings (89%), while 48% of them worked in southern Italy. 97% of respondents considered mpMRI useful to detect Prostate Cancer (PCa) in patients with prior negative biopsy, 64% in biopsy-naïve patients and 60% for PCa pre-operatory staging. About half (42%) of the participants declared that mpMRI results frequently lead them to change PCa management strategy. Standardization of mpMRI acquisition and reporting was partially unsatisfactory. Reported waiting time for mpMRI scans was longer than 4 weeks for 51% of respondents. The major limitation of this survey includes the small number of participants.

CONCLUSIONS

Prostate mpMRI is used by Italian urologists mainly for detection and for pre-operative staging of PCa. Further improvements in terms of mpMRI availability and report standardization are required.

Performance of prostate multiparametric MRI for prediction of prostate cancer extra-prostatic extension according to NCCN risk categories: implication for surgical planning

BACKGROUND

Prediction of extra-prostatic extension (EPE) in men undergoing radical prostatectomy (RP) is of utmost importance. Great variability in the performance of multiparametric magnetic resonance imaging (mpMRI) has been reported for prediction of EPE. The present study aimed to determine the diagnostic performance of mpMRI for predicting EPE in different National Comprehensive Cancer Network (NCCN) risk categories.

METHODS

Overall 664 patients who underwent radical prostatectomy with a staging mpMRI were enrolled in this single-center, retrospective study. Patients with mpMRI report non-compliant with PI-RADSv2.0, were excluded. Patients were stratified according to NCCN criteria: very low/low (VLR-LR) to High Risk (HR) in order to assess final pathology EPE rates (focal and established). Sensitivity, specificity, positive and negative predictive values of staging mpMRI were computed in each group. Univariable and multivariable analysis were used to evaluate predictors of positive surgical margins.

RESULTS

Pathological evaluation demonstrated established and focal EPE in 60 (9%) and 106 (16%) patients, respectively, while mpMRI suspicion for EPE was present in 180 (27%) patients. Age, preoperative PSA, PSA density, number of positive cores, NCCN groups, prostate volume, mpMRI suspicion for EPE, PIRADSv2.0 and lesion size differed significantly between the patients with any EPE and without EPE (all P≤0.05). The sensitivity of mpMRI in detecting any EPE varied from 12% (95% CI: 0.6-53%) in VLR-LR to 83% (66-93%) in HR while the corresponding values for the specificity were 92% (85-96%) and 63% (45-78%), respectively. Patients with false-negative mpMRI EPE prediction were more likely to have positive surgical margins in univariable (OR: 2.14; CI: 1.18, 3.87) as well as multivariable analysis adjusting for NCCN risk categories (OR: 1.97; CI: 1.08, 3.60).

CONCLUSIONS

The performance of mpMRI for prediction of EPE varies greatly between different NCCN risk categories with a low positive predicting value in patients at low to favorable intermediate risk and a low negative predictive value in patients at Unfavorable intermediate to high risk PCa. Given that mpMRI EPE misdiagnosis could have a negative impact on oncological and functional outcomes, NCCN risk categories should be considered when interpreting mpMRI findings in PCa patients.

Three-dimensional Elastic Augmented-reality Robot-assisted Radical Prostatectomy Using Hyperaccuracy Three-dimensional Reconstruction Technology: A Step Further in the Identification of Capsular Involvement

BACKGROUND

In prostate cancer (PCa) surgical procedures, in order to maximize potency recovery, a nerve-sparing (NS) procedure is preferred. However, cancer abutting or focally extending beyond the prostate capsule increases the risk of a positive surgical margin.

OBJECTIVE

To evaluate the accuracy of our new three-dimensional (3D) elastic augmented-reality (AR) system in identifying capsular involvement (CI) location of PCa during the NS phase of robot-assisted radical prostatectomy (RARP). Secondarily, the accuracy of this technology was compared with two-dimensional (2D)-based cognitive procedures.

DESIGN, SETTING, AND PARTICIPANTS

A prospective study, enrolling 40 patients with PCa undergoing RARP at our center, from May to October 2018.

SURGICAL PROCEDURE

Patients underwent 3D AR RARP or, in case of unavailability of this technology, 2D cognitive RARP. In all patients, total anatomical reconstruction was used.

MEASUREMENTS

Clinical data were collected. In order to compare the two groups, nonparametric Mann-Whitney and chi-square tests were performed. A metallic clip was placed at the level of suspicious CI on the basis of images given by the 3D AR or magnetic resonance imaging (MRI) report. The pathological analysis evaluated the presence of tumor at the level of the clip.

RESULTS AND LIMITATIONS

Twenty patients were enrolled in each group. Focusing on the 3D AR group at macroscopic evaluation, the metallic clip was placed at the tumor and capsular bulging in all cases. At microscopic assessment, cancer presence was confirmed in the suspicious area in 95.4% of the cases. Moreover, CI was correctly identified in 100.0% of the cases, thanks to the 3D image overlap. These results were compared with the 2D MRI cognitive group, showing, at microscopic analysis, statistically significant superiority of the 3D AR group in CI detection during the NS phase (100% vs 47.0%; p<0.05). The main limitation of this technique is that the segmentation and overlapping of the images are performed manually.

CONCLUSIONS

Our findings suggest that, with the introduction of the elastic 3D virtual models, prostate deformation is correctly simulated during surgery and lesion location is correctly identified, even in dynamic reality with a subsequent potential reduction of positive surgical margin rate and, in the meantime, maximization of functional outcomes.

PATIENT SUMMARY

On the basis of our findings, the three-dimensional elastic augmented-reality technology seems to help the surgeon in lesion location identification even in a dynamic phase of the intervention, optimizing the oncological outcomes.