Efficacy of using three-tesla magnetic resonance imaging diagnosis of capsule invasion for decision-making about neurovascular bundle preservation in robotic-assisted radical prostatectomy

Selection of patients for nerve sparing surgery in robot‐assisted radical prostatectomy

Context

Robot‐assisted radical prostatectomy (RARP) has become the standard surgical procedure for localized prostate‐cancer (PCa). Nerve‐sparing surgery (NSS) during RARP has been associated with improved erectile function and continence rates after surgery. However, it remains unclear what are the most appropriate indications for NSS.

Objective

The objective of this study is to systematically review the available parameters for selection of patients for NSS. The weight of different clinical variables, multiparametric magnetic‐resonance‐imaging (mpMRI) findings, and the impact of multiparametric‐nomograms in the decision‐making process on (side‐specific) NSS were assessed.

Evidence acquisition

This systematic review searched relevant databases and included studies performed from January 2000 until December 2020 and recruited a total of 15 840 PCa patients. Studies were assessed that defined criteria for (side‐specific) NSS and associated them with oncological safety and/or functional outcomes. Risk of bias assessment was performed.

Evidence synthesis

Nineteen articles were eligible for full‐text review. NSS is primarily recommended in men with adequate erectile function, and with low‐risk of extracapsular extension (ECE) on the side‐of NSS. Separate clinical and radiological variables have low accuracy for predicting ECE, whereas nomograms optimize the risk‐stratification and decision‐making process to perform or to refrain from NSS when oncological safety (organ‐confined disease, PSM rates) and functional outcomes (erectile function and continence rates) were assessed.

Conclusions

Consensus exists that patients who are at high risk of ECE should refrain from NSS. Several multiparametric preoperative nomograms were developed to predict ECE with increased accuracy compared with single clinical, pathological, or radiological variables, but controversy exists on risk thresholds and decision rules on a conservative versus a less‐conservative surgical approach. An individual clinical judgment on the possibilities of NSS set against the risks of ECE is warranted.

Patient summary

NSS is aimed at sparing the nerves responsible for erection. NSS may lead to unfavorable tumor control if the risk of capsule penetration is high. Nomograms predicting extraprostatic tumor‐growth are probably most helpful.

Prostate cancer local staging using biparametric MRI: assessment and comparison with multiparametric MRI

PURPOSE

The value of adding dynamic contrast-enhanced (DCE) imaging to T2-weighted (T2W) magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) to improve the detection and staging of prostate cancer (PCa) is unclear. The aim of this retrospective study was to compare the diagnostic performance of non-contrast biparametric MRI (bpMRI) with multiparametric MRI (mpMRI), for local staging of PCa.

METHODS

Ninety-two patients who underwent prostate MRI on a 3-Tesla MRI system before radical prostatectomy for PCa were included retrospectively. Four readers independently assigned a Likert score (ranging from 1 to 5) for predicting extra-prostatic extension (EPE) on T2W + DWI (bpMRI) and then on T2W + DWI + DCE imaging (mpMRI). MRI-based staging results were compared with radical prostatectomy histology. A prediction of EPE generalized linear mixed model was used to assess the added-value of DCE and discriminative power of staging accuracy by area under the receiver-operating curve (AUC ROC).

RESULTS

AUC was not significantly improved by DCE (mpMRI, AUC = 0.73 [95%CI: 0.655‒0.827] vs. bpMRI, AUC = 0.76 [95%CI: 0.681‒0.846]). After applying a selection procedure, only MRI criteria were retained in a multivariate model. The following criteria were significantly associated with local extension: localization in the peripheral zone (p < 0.001), maximal diameter of the lesion (<0.0001), curvilinear capsular contact on T2W (p < 0.0001), capsular irregularity on T2W (p < 0.0001), bulging on T2W (p < 0.001) and seminal vesicle hypo-signal (p < 0.001).

CONCLUSION

Use of bpMRI did not result in a decrease in local staging accuracy.

Prostate MRI: staging and decision-making

Multi-parametric prostate MRI (mpMRI) plays a critical role in the diagnosis, staging, and evaluation of treatment response in patients with prostate cancer. Radiologists, through an accurate and standardized interpretation of mpMRI, can clinically stage prostate cancer and help to risk stratify patients who may benefit from more invasive treatment or exclude patients who may be harmed by overtreatment. The purpose of this article is to describe key findings to accurately stage prostate cancer with mpMRI and to describe the contexts in which mpMRI is best applied.

Accuracy of multiparametric magnetic resonance imaging for detecting extracapsular extension in prostate cancer: a systematic review and meta-analysis

OBJECTIVE

To evaluate the diagnostic accuracy of multiparametric MRI (mpMRI) for detecting extracapsular extension (ECE) in patients with prostate cancer (PCa).

METHODS AND MATERIALS

We searched MEDLINE, PubMed, Embase and the Cochrane library up to December 2018. We included studies that used mpMRI to differentiate ECE from organ-confined PCa with a combination of T₂ weighted imaging (T₂WI), diffusion-weighted imaging, and dynamic contrast-enhanced MRI. All studies included had pathological diagnosis with radical prostatectomy. Two reviewers independently assessed the methodological quality of included studies by using Quality Assessment of Diagnostic Accuracy Studies 2 tool. We calculated pooled sensitivity, specificity, positive and negative predictive values, diagnostic odds ratios and receiver operating characteristic curve for mpMRI from 2 × 2 tables.

RESULTS

A total of 17 studies that comprised 3374 participants were included. The pooled data showed a sensitivity of 0.55 (95% confidence interval 0.43, 0.66]) and specificity of 0.87 (95% confidence interval 0.82, 0.91) for extracapsular extension detection in PCa.

CONCLUSION

First, our meta-analysis shows moderate sensitivity and high specificity for mpMRI to differentiate ECE from organ-confined prostate cancer before surgery. Second, our meta-analysis shows that mpMRI had no significant differences in performance compared with the former meta-analysis with use of T₂WI alone or with additional functional MRI.

ADVANCES IN KNOWLEDGE

It is the first meta-analysis to evaluate the accuracy of mpMRI in combination of TWI, diffusion-weightedimaging and dynamiccontrast-enhanced-MRI for extracapsular extension detection.

3.0-T multiparametric magnetic resonance imaging modifies the template of endoscopic, conventional radical prostatectomy in all cancer risk categories

INTRODUCTION

We aimed to evaluate the diagnostic performance of 3.0-T multiparametric magnetic resonance imaging (mpMRI) in preoperative staging of prostate cancer (PCa) and its influence on the extent of resection during endoscopic radical prostatectomy (ERP) among cancer risk groups.

MATERIAL AND METHODS

The data of 154 patients with PCa in whom mpMRI was performed prior to ERP between 2011 and 2015 were included. The initial decision whether to perform neurovascular bundle (NVB) sparing surgery was based on EAU guidelines. mpMRI images were reevaluated prior to prostatectomy to modify the surgical template. Imaging was compared with pathological reports to investigate the diagnostic performance of mpMRI.

RESULTS

The surgical template was modified in 69 (44.8%) patients after reevaluation of mpMRI. More preserving NVB sparing was attempted in 17 (11.0%) men, in whom NVB would have been resected if mpMRI had not been available. More aggressive NVB resection was performed in 52 (33.8%) men, in whom innervation would have been spared if basing solely based on guidelines. Among all PCa risk groups mpMRI had an impact on the surgical template with more aggressive surgery in 63.0% and 33.3% of men in the low- and intermediate-risk group, respectively, and more preserving in 21.4% of the high-risk patients. The change in extent of resection was not correlated with a higher risk of positive surgical margins (p = 0.196).

CONCLUSIONS

Preoperative mpMRI exerts a significant impact on decision making concerning the extent of resection during ERP irrespective of the PCa risk group.

The value of periprostatic fascia thickness and fascia preservation as prognostic factors of erectile function after nerve-sparing robot-assisted radical prostatectomy

PURPOSE

To determine the correlation of preoperative fascia thickness (FT) and intraoperative fascia preservation (FP) with erectile function (EF) after nerve-sparing robot-assisted radical prostatectomy (RARP).

METHODS

Our analysis included 106 patients, with localized prostate cancer and no erectile dysfunction (ED) before RARP, assessed with preoperative 3 Tesla (3 T) multiparametric magnetic resonance imaging (MRI). FP score was defined as the extent of FP from the base to the apex of the prostate, quantitatively assessed by the surgeon. Median fascia thickness (MFT) per patient was defined as the sum of the median FT of 12 MRI regions. Preserved MFT (pMFT) was the sum of the saved MFT. The percentage of pFMT (ppMFT) was also calculated. Fascia surface (FS) was measured on MRI and it was combined with FP score resulting in preserved FS (pFS) and percentage of pFS (ppFS).

RESULTS

FP score, pMFT, ppMFT, pFS and ppFS were significantly lower (p < 0.0001) in patients with ED. In the multivariate regression analysis, lower FP score [odds ratio (OR) 0.721, p = 0.03] and lower ppMFT (OR 0.001, p = 0.027) were independent predictors of ED. ROC analysis showed the highest area under the curve for ppMFT (0.787) and FP score (0.767) followed by pMFT (0.755) and ppFS (0.743).

CONCLUSIONS

MRI-determined periprostatic FT combined with intraoperative FP score are correlated to postprostatectomy EF. Based on the hypothesis that a thicker fascia forms a protective layer for the nerves, we recommend assessing FT preoperatively to counsel men for the odds of preserving EF after RARP.

Neurovascular bundle size measured on 3.0-T magnetic resonance imaging is associated with the recovery of erectile function after robot-assisted radical prostatectomy

BACKGROUND AND OBJECTIVE

Erectile dysfunction is one of the complications occurring after radical prostatectomy (RP), and recovery of erectile function is quantitatively related to the preservation of the neurovascular bundles (NVB).We evaluated the significance of NVB area on functional outcomes after RP.

MATERIALS AND METHODS

Preoperative magnetic resonance imaging was performed on 141 patients who underwent bilateral, nerve-sparing, robot-assisted RP for clinically localized prostate cancer (clinically T2N0M0 on magnetic resonance imaging) and were evaluated at least 12 months after surgery. NVB area was measured as a region of interest that coincided with the outline of the maximum area of the posterolateral region of the prostate on T2-weighted axial imaging. Factors associated with functional outcomes were evaluated using logistic regression analysis.

RESULTS

Of 141 patients, 36 patients (25.5%) had no preoperative potency (group 1), 66 patients (46.8%) recovered potency (group 2), and 39 patients (27.7%) did not recover potency (group 3). Although the mean age of the entire cohort was 65.4 years, the mean age of group 1 was greater than groups 2 and 3 (P = 0.001). The NVB area of group 2 was larger than those of groups 1 and 3 (P = 0.001). Potency evaluations involved 105 patients (74.5%; groups 2 and 3), and patients with pre-existing erectile dysfunction were excluded. The median time to potency recovery was 3.0 months after surgery. The multivariable analysis revealed that the NVB area was the only significant factor predictive of potency recovery.

CONCLUSIONS

The NVB area in the posterolateral region of the prostate is an independent factor for predicting potency recovery. The degree of postoperative erectile function can be predicted based on the preoperative NVB area.

Intraoperative Frozen Section of the Prostate Reduces the Risk of Positive Margin Whilst Ensuring Nerve Sparing in Patients with Intermediate and High-Risk Prostate Cancer Undergoing Robotic Radical Prostatectomy: First Reported UK Series

INTRODUCTION

Nerve sparing during robotic radical prostatectomy (RRP) considerably improves post-operative potency and urinary continence as long as it does not compromise oncological outcome. Excision of the neurovascular bundle (NVB) is often performed in patients with intermediate and high risk prostate cancer to reduce the risk of positive surgical margin raising the risk of urinary incontinence and impotence. We present the first UK series outcomes of such patients who underwent an intra-operative frozen section (IOFS) analysis of the prostate during RRP allowing nerve sparing.

PATIENTS AND METHODS

We prospectively analysed the data of 40 patients who underwent an IOFS during RRP at our centre from November 2012 until November 2014. Our IOFS technique involved whole lateral circumferential analysis of the prostate during RRP with the corresponding neurovascular tissue. An intrafascial nerve spare was performed and the specimen was removed intra-operatively via an extension of the 12 mm Autosuture™ camera port without undocking robotic arms. It was then painted by the surgeon and sprayed with "Ink Aid" prior to frozen section analysis. The corresponding NVB was excised if the histopathologist found a positive surgical margin on frozen section.

RESULTS

Median time to extract the specimen, wound closure and re-establishment of pneumoperitoneum increased the operative time by 8 min. Median blood loss for IOFS was 130 ± 97 ml vs. 90 ± 72 ml (p = NS). IOFS was not associated with major complications or with blood transfusion. PSM decreased significantly from non-IOFS RRP series of 28.7 to 7.8% (p < 0.05). Intra-operative PSM on the prostate specimen was seen in 8/40 margin analysis (20%) leading to an excision of the contra-lateral nerve bundle. On analysis of the nerve bundle on a paraffin embedded block, 6 nerve bundle matched tumor on the specimen whereas 2 NVB were retrospectively removed unnecessarily in our series. All 40 patients have undetectable PSA at a mean follow up of 21.2 months (SD 7.79). Functional data at 18 months confirms a reduction in the urinary incontinence from 37% in the IOFS group vs 57% in the non-IOFS group (p = NS). IOFS technique has resulted in a significant increase in intravesical nerve sparing in both T2/T3 patients with intermediate and high risk prostate cancer when appropriately counselled and selected (T2 from 100% in the IOFS group versus 67% and T3 from 100% in the IOFS group to 42%) (p < 0.05).

CONCLUSION

Introduction of the IOFS analysis during intrafascial nerve spare RRP has reduced PSM and the rate of urinary incontinence.

Accuracy of Multiparametric Magnetic Resonance Imaging for Extracapsular Extension of Prostate Cancer in Community Practice

INTRODUCTION

The presence of extracapsular extension (ECE) in prostate cancer (PCa) can influence a surgeon's decision to perform a nerve-sparing approach during radical prostatectomy (RP). Preoperatively, multiparametric MRI (mp-MRI) is often used to stage PCa. More recently, the use of mp-MRI has gained wide acceptance in fusion biopsy of the prostate. In this framework, the reported accuracy of mp-MRI has been highly variable, with data often originating from large referral centers with experienced radiologists. We sought to determine the sensitivity and specificity of mp-MRI for detecting ECE in the community.

MATERIALS AND METHODS

We reviewed a prospectively maintained database of men with PCa who had undergone RP. We recorded the prevalence of ECE at RP and determined the sensitivity, specificity, positive predictive value, and negative predictive value of MRI for detecting ECE. We assessed these values according to the D'Amico risk groups and compared the predictive value of MRI to that of the Partin tables.

RESULTS

The prevalence of ECE was 11.5%, 28.1%, and 47.1% in the low-, intermediate, and high-risk groups, respectively, with an overall prevalence of 24.1%. The overall sensitivity, specificity, positive predictive value, and negative predictive value of MRI was 12.5%, 93.1%, 36.4%, and 77.0%, respectively.

CONCLUSION

The reduction in the sensitivity of preoperative mp-MRI to determine ECE in the community setting is significant. Even with stratification using the D'Amico criteria and Partin tables, the performance of mp-MRI was not significantly improved. Because most cases of PCa are diagnosed and treated in the community, it is questionable whether mp-MRI is a suitable staging modality in the community.

Novel methods for mapping the cavernous nerves during radical prostatectomy

The cavernous nerves, which course along the surface of the prostate gland, are responsible for erectile function. During radical prostatectomy, urologists are challenged in preserving these nerves and their function. Cavernous nerves are microscopic and show variable location in different patients; therefore, postoperative sexual potency rates are widely variable following radical prostatectomy. A variety of technologies, including electrical and optical nerve stimulation, dye-based optical fluorescence and microscopy, spectroscopy, ultrasound and magnetic resonance imaging have all been used to study cavernous nerve anatomy and physiology, and some of these methods are also potential intraoperative methods for identifying and preserving cavernous nerves. However, all of these technologies have inherent limitations, including slow or inconsistent nerve responses, poor image resolution, shallow image depth, slow image acquisition times and/or safety concerns. New and emerging technologies, as well as multimodal approaches combining existing methods, hold promise for improved postoperative sexual outcomes and patient quality of life following radical prostatectomy.

Magnetic resonance imaging for prostate cancer: Comparative studies including radical prostatectomy specimens and template transperineal biopsy

Purpose

Multiparametric magnetic resonance imaging (mpMRI) is an emerging technique aiming to improve upon the diagnostic sensitivity of prostate biopsy. Because of variance in interpretation and application of techniques, results may vary. There is likely a learning curve to establish consistent reporting of mpMRI. This study aims to review current literature supporting the diagnostic utility of mpMRI when compared with radical prostatectomy (RP) and template transperineal biopsy (TTPB) specimens.

Methods

MEDLINE and PubMed database searches were conducted identifying relevant literature related to comparison of mpMRI with RP or TTPB histology.

Results

Data suggest that compared with RP and TTPB specimens, the sensitivity of mpMRI for prostate cancer (PCa) detection is 80–90% and the specificity for suspicious lesions is between 50% and 90%.

Conclusions

mpMRI has an increasing role for PCa diagnosis, staging, and directing management toward improving patient outcomes. Its sensitivity and specificity when compared with RP and TTPB specimens are less than what some expect, possibly reflecting a learning curve for the technique of mpMRI.

Diagnosis of Extracapsular Extension of Prostate Cancer on Prostate MRI: Impact of Second-Opinion Readings by Subspecialized Genitourinary Oncologic Radiologists

OBJECTIVE

The purpose of this article is to investigate the added value of second-opinion evaluation of prostate MRI by subspecialized genitourinary oncologic radiologists for the assessment of extracapsular extension (ECE) of prostate cancer.

MATERIALS AND METHODS

We performed a retrospective evaluation of initial and second-opinion radiology reports of 76 patients who underwent MRI of the prostate before prostatectomy for histologically proven prostate cancer. Initial outside reports and second-opinion reports were unpaired and reviewed in random order by a urologist who was blinded to patients' clinical details and histopathologic data. Histopathologic analysis of the prostatectomy specimen served as the reference standard.

RESULTS

Among cases with diagnostic-quality images available (71/76; 93%), disagreement between the initial report and the second-opinion report was observed in 30% of cases (21/71; κ = 0.35); in 18 of these 21 cases (86%), histopathologic analysis proved that the second-opinion report was correct. The second-opinion interpretations had statistically significantly higher sensitivity (66% vs 24%; p < 0.0001) than did the initial reports, whereas there was no statistically significant difference in specificity (87% vs 93%; p = 0.317). On ROC curve analysis, the second-opinion reports yielded a statistically significantly higher AUC for the detection of ECE (0.80 vs 0.65; p = 0.004).

CONCLUSION

The reinterpretation of prostate MRI examinations by subspecialized genitourinary oncologic radiologists improved the detection of ECE of prostate cancer.

Current role of multiparametric magnetic resonance imaging in the management of prostate cancer

The purpose of this review was to evaluate the current role of multiparametric magnetic resonance imaging (mp-MRI) in the management of prostate cancer (PC). The diagnosis of PC remains controversial owing to overdetection of indolent disease, which leads to overtreatment and subsequent patient harm. mp-MRI has the potential to equilibrate the imbalance between detection and treatment. The limitation of the data for analysis with this new technology is problematic, however. This issue has been compounded by a paradigm shift in clinical practice aimed at utilizing this modality, which has been rolled out in an ad hoc fashion often with commercial motivation. Despite a growing body of literature, pertinent clinical questions remain. For example, can mp-MRI be calibrated to reliably detect biologically significant disease? As with any new technology, objective evaluation of the clinical applications of mp-MRI is essential. The focus of this review was on the evaluation of mp-MRI of the prostate with respect to clinical utility.

Value of preoperative MRI for prostate cancer staging and continence outcomes prior to prostatectomy: A review of the literature

Pelvic imaging in newly diagnosed prostate cancer is primarily used for staging prior to definitive treatment. Over the past decade use of magnetic resonance imaging (MRI) for pre-surgical planning has increased, as well has he technology and methods for performing prostate MRI. To investigate and define the different MRI technologies available and further assess MRI technology ability to predict pathologic stage. Searching PubMed, we identified current published literature, where the cohort population underwent pre-operative MRI followed by prostatectomy. Keywords used in the PubMed literature search included: MRI, prostate cancer, prostate cancer staging, multiparamentric MRI and incontinence. Papers were included for review if they discussed use of MRI prior to prostatectomy and had corresponding pathologic data, staging, incontinence, and surgical outcomes. Primary information noted was MRI sensitivity, specificity and overall accuracy for detecting extracapsular extension (ECE) and seminal vesicle involvement (SVI). Secondary information derived included assessing the surgical influence of staging information, and identifying predictors of urinary incontinence recovery. Review of the literature showed that in regards to extracapsular extension the reported MRI accuracy ranged from 76%-98%, sensitivity from 20%-90% and specificity from 82%-99%. As for seminal vesicle involvement the reported MRI accuracy ranged from 76%-98%, sensitivity from 20%-90% and specificity from 82%-99%. There is a widely varying sensitivity and specificity for both ECE and SVI and the wide variability in the MRI technology used in the literature supports that use of MRI technology for prostate cancer remains investigational.