Patterns of Benign Prostate Hyperplasia Based on Magnetic Resonance Imaging Are Correlated With Lower Urinary Tract Symptoms and Continence in Men Undergoing a Robot-assisted Radical Prostatectomy for Prostate Cancer

Membranous urethral length measurement on preoperative MRI to predict incontinence after radical prostatectomy: a literature review towards a proposal for measurement standardization

OBJECTIVES

To investigate the membranous urethral length (MUL) measurement and its interobserver agreement, and propose literature-based recommendations to standardize MUL measurement for increasing interobserver agreement. MUL measurements based on prostate MRI scans, for urinary incontinence risk assessment before radical prostatectomy (RP), may influence treatment decision-making in men with localised prostate cancer. Before implementation in clinical practise, MRI-based MUL measurements need standardization to improve observer agreement.

METHODS

Online libraries were searched up to August 5, 2022, on MUL measurements. Two reviewers performed article selection and critical appraisal. Papers reporting on preoperative MUL measurements and urinary continence correlation were selected. Extracted information included measuring procedures, MRI sequences, population mean/median values, and observer agreement.

RESULTS

Fifty papers were included. Studies that specified the MRI sequence used T2-weighted images and used either coronal images (n = 13), sagittal images (n = 18), or both (n = 12) for MUL measurements. 'Prostatic apex' was the most common description of the proximal membranous urethra landmark and 'level/entry of the urethra into the penile bulb' was the most common description of the distal landmark. Population mean (median) MUL value range was 10.4-17.1 mm (7.3-17.3 mm), suggesting either population or measurement differences. Detailed measurement technique descriptions for reproducibility were lacking. Recommendations on MRI-based MUL measurement were formulated by using anatomical landmarks and detailed descriptions and illustrations.

CONCLUSIONS

In order to improve on measurement variability, a literature-based measuring method of the MUL was proposed, supported by several illustrative case studies, in an attempt to standardize MRI-based MUL measurements for appropriate urinary incontinence risk preoperatively.

CLINICAL RELEVANCE STATEMENT

Implementation of MUL measurements into clinical practise for personalized post-prostatectomy continence prediction is hampered by lack of standardization and suboptimal interobserver agreement. Our proposed standardized MUL measurement aims to facilitate standardization and to improve the interobserver agreement.

KEY POINTS

• Variable approaches for membranous urethral length measurement are being used, without detailed description and with substantial differences in length of the membranous urethra, hampering standardization. • Limited interobserver agreement for membranous urethral length measurement was observed in several studies, while preoperative incontinence risk assessment necessitates high interobserver agreement. • Literature-based recommendations are proposed to standardize MRI-based membranous urethral length measurement for increasing interobserver agreement and improving preoperative incontinence risk assessment, using anatomical landmarks on sagittal T2-weighted images.

Quality of life after non-nerve-sparing, robot-assisted radical prostatectomy

OBJECTIVE

To evaluate quality of life (QOL) after non-nerve-sparing, robot-assisted radical prostatectomy (RARP) and factors associated with worsened QOL.

METHODS

Patients who underwent non-nerve-sparing RARP (n = 115) were enrolled. The Expanded Prostate Cancer Index Composite and 8-item Short Form Health Survey were used to evaluate QOL at baseline and postoperative 1, 3, 6, 12, and 24 months. Preoperative factors were evaluated by multivariate analysis for worsened QOL.

RESULTS

Postoperative 24-month urinary QOL worsened in 68 of 115 (59%) patients. In multivariate analysis, membranous urethral length ≥10.8 mm [odds ratio (OR): .26, 95% confidence interval (CI): .07-.96] and intravesical prostatic protrusion ≥12 mm (OR: .14, 95% CI .06-.35) were significantly associated with maintaining postoperative 24-month urinary QOL. Significantly more patients with intravesical prostatic protrusion ≥12 mm than < 12 mm had improved urinary QOL. At postoperative 24 months, 43 of 115 (38%) patients had worsened sexual QOL. In multivariate analysis, higher Sexual Health Inventory for Men score (OR: 8.39, 95% CI 2.28-30.9), sexual activity (OR: 6.94, 95% CI: 2.27-21.2), and intercourse activity (OR: 6.81, 95% CI: 1.64-28.3) preoperatively were significantly associated with worsened postoperative 24-month sexual QOL. More patients with high preoperative intercourse activity (12/23,53%) had significantly worsened (p = .009) QOL regarding sexual bother than those who had no preoperative intercourse activity (21/92, 23%).

CONCLUSION

After non-nerve-sparing RARP, patients with long membranous urethral length and/or intravesical prostatic protrusion maintain urinary QOL. Patients with high intercourse activity presented with impairment of sexual QOL after non-nerve-sparing RARP.

Influence of benign prostatic hyperplasia patterns detected with MRI on the clinical outcome after prostatic artery embolization

BACKGROUND

To investigate the influence of benign prostatic hyperplasia (BPH) patterns detected with MRI on clinical outcomes after prostatic artery embolization (PAE).

MATERIALS & METHODS

This retrospective study included 71 consecutive patients with lower urinary tract symptoms (LUTS), who underwent magnetic resonance imaging (MRI) of the prostate followed by PAE at a single centre. MRI scans were evaluated and BPH patterns were determined according to Wasserman type and a modified BPH classification. Additionally, scans were evaluated regarding the presence of adenomatous-dominant benign prostatic hyperplasia (AdBPH). LUTS were assessed using the International Prostate Symptom Score (IPSS) and urinary flow rate (Qmax). Follow-up examination included MRI and clinical outcome.

RESULTS

For clinical outcome at follow-up, IPSS showed median reduction of 54% (IQR 41-75%) and Qmax improved by 4.1 ml/s. We noted significant reduction in volume, intraprostatic protrusion, and prostatic urethral angle in our collective (p < 0.01). Median volume reduction was 25% (IQR 15%-34%). Bilateral embolization was a significant predictor for volume reduction at follow-up. Multiple linear regression analysis showed significant effect of high initial volume on reduction in IPSS after treatment (p < 0.01). Presence of AdBPH was significantly associated with both, volume loss and clinical improvement in terms of IPSS reduction (p < 0.01). Neither BPH pattern based on the Wassermann type nor modified BPH classification were significantly related with postinterventional IPSS and volume loss.

CONCLUSIONS

Men benefit from PAE regardless the macroscopic BPH MRI pattern. Preinterventional prostate volume and presence of AdBPH on MRI should be considered for outcome prognosis after PAE.

Clinical Factors Associated With Pathological Grade Group 1 Patients in D'Amico Intermediate-Risk Group Following Robot-Assisted Radical Prostatectomy: A Retrospective Multicenter Cohort Study in Japan (The MSUG94 Group)

INTRODUCTION

We aimed to examine the relationship between D'Amico intermediate-risk and pathological grade group 1 (pGG1) after robot-assisted radical prostatectomy (RARP).

PATIENTS AND METHODS

In this retrospective multicenter cohort study, D'Amico intermediate-risk prostate cancer patients who did not receive neoadjuvant therapy, and underwent RARP at 10 institutions in Japan were examined for preoperative factors associated with pGG1.

RESULTS

In total, we enrolled 1161 D'Amico intermediate-risk prostate cancer patients. The pGG1 and pGG ≥2 groups comprised 73 (6.3%), and 1088 (93.7%) cases, respectively. Biochemical recurrence-free survival (BCRFS) of the pGG1 group was equivalent to that of the D'Amico low-risk patients. Among the 3 D'Amico intermediate-risk factors (IRF), the pGG1-rate was 24% with prostate-specific antigen (PSA) of 10 to 20 ng/mL alone, and 30% with cT2b alone. Both groups had significantly higher pGG1-rates than other groups. Down-grading from biopsy GG ≥2 to pGG1 was relatively rare (3.9%). Patients with pGG1 were further stratified by prostate volume (PV) (cutoff, 40 cc) among patients with one IRF and PSA of 10 to 20 ng/mL. Patients with one IRF, PSA of 10 to 20 ng/mL, and PV >40 cc had a relatively good BCRFS similar to that of the D'Amico low-risk group.

CONCLUSION

Among intermediate-risk prostate cancer patients, those with pGG1 have a good prognosis. Downgrading from biopsy GG ≥2 is rare, and definitive treatment may be recommended for patients with biopsy GG ≥2. Patients with one IRF, PSA of 10 to 20 ng/mL, and PV >40 cc who are eligible for RARP may be candidates for active surveillance.

Minimal residual membranous urethral length and membranous urethral length predict poor recovery from incontinence after robot-assisted radical prostatectomy and after open radical prostatectomy

OBJECTIVES

To investigate how much minimal residual membranous urethral length (mRUL) and maximal urethral length (MUL) measured on MRI preoperatively affect postoperative urinary incontinence (PUI) and recovery in robot-assisted radical prostatectomy (RARP) and open radical prostatectomy (ORP).

METHODS

The subjects were 190 and 110 patients undergoing RARP and ORP, respectively, in our institution. Patients underwent preoperative MRI for prostate cancer evaluation and completed the quality of life questionnaire of the Expanded Prostate Cancer Index Composite instrument before and 1, 3, 6, and 12 months after surgery. The parameters of mRUL and MUL were measured on MRI and analyzed along with other parameters including age, body mass index, and nerve sparing.

RESULTS

The median mRUL and MUL were 7.81 and 14.27 mm in the RARP group and 7.15 and 13.57 mm in the ORP group, respectively. Recovery rates from PUI were similar in the two groups. Multivariate analyses showed that mRUL was a predictor of baseline continence, whereas shorter MUL was a predictor of poor recovery from PUI. Patients with both shorter mRUL and MUL had significantly worse recoveries from PUI after RARP and ORP than patients with longer mRUL and MUL.

CONCLUSIONS

Minimal residual membranous urethral length contributes to urethral function as basal urinary continence, whereas MUL represents the potential of recovery from PUI in RARP and ORP. The MUL measured by preoperative MRI can predict poor recovery from PUI after radical prostatectomy and combined evaluation of MUL and mRUL support to anticipate poor recovery of PUI.

Value of Different Magnetic Resonance Imaging-based Measurements of Anatomical Structures on Preoperative Prostate Imaging in Predicting Urinary Continence After Radical Prostatectomy in Men with Prostate Cancer: A Systematic Review and Meta-analysis

CONTEXT

Measurements of anatomical structures on preoperative prostate magnetic resonance imaging (MRI) are used in risk models for treatment decisions to predict urinary continence (UC) following radical prostatectomy (RP). However, the association between these parameters and UC is unclear.

OBJECTIVE

To systematically summarize the literature on prognostic preoperative prostate MRI measurements of (peri)prostatic structures in relation to time to recovery of postoperative UC in men with prostate cancer.

EVIDENCE ACQUISITION

Online libraries were searched up to August 27, 2021. Article selection and critical appraisal were performed by two reviewers. All papers reporting on preoperative MRI measurements with UC correlation in univariable or multivariable analyses were included.

EVIDENCE SYNTHESIS

In the 50 studies included (mostly retrospective), 57 MRI parameters were evaluated. The pooled analyses showed that greater membranous urethra length (MUL) was prognostic for regaining UC at 1 mo (odds ratio [OR] 1.15, 95% confidence interval [CI] 1.10-1.21), 3 mo (OR 1.23, 95% CI 1.16-1.31), 6 mo (OR 1.16, 95% CI 1.08-1.25), and 12 mo (OR 1.19, 95% CI 1.10-1.29). Several other anatomical structures showed at least in one study a significant correlation with later return to UC: four prostate-related parameters (greater depth, apical protrusion, larger intravesical protrusion, small dorsal vascular complex), five urethra-related parameters (thicker wall, severe fibrosis, smaller volume, larger preoperative angle between the prostate axis and membranous urethra, shorter minimal residual MUL), and six musculoskeletal-related parameters (lower perfusion ratio, thinner levator ani muscle, larger inner or outer levator distance, shorter pelvic diaphragm length, and larger midpelvic area).

CONCLUSIONS

Greater MUL as measured on preoperative MRI was an independent prognostic factor for return to UC within 1 mo after RP and remained prognostic at 12 mo. Other anatomical structures may potentially be predictive, but these would need to be substantiated in prospective trials before being adopted in postoperative UC risk models for treatment decisions in men with prostate cancer.

PATIENT SUMMARY

We summarized study data on the relation between measurements of anatomical structures on preoperative magnetic resonance imaging scans and urinary continence after removal of the prostate. Greater length of one part of the urethra (membranous urethra) is associated with faster return to continence. Other anatomical structures have potential for predicting postoperative continence, but need further investigation.

MRI Features Associated with Histology of Benign Prostatic Hyperplasia Nodules: Generation of a Predictive Model

Background: Histologic phenotypic variation of benign prostatic hyperplasia (BPH) has been hypothesized to underlie response to medical therapy. We evaluate preoperative MRI of robot-assisted simple prostatectomy (RASP) specimens and determine imaging features associated with histologic phenotype. Materials and Methods: All patients undergoing RASP from November 2015 to November 2019 with a multiparametric MRI ≤1 year before RASP were included. Patients without identifiable BPH nodules on histologic specimens were excluded. Histology slides were obtained from whole mount adenoma specimens and corresponding MRI were reviewed and graded independently by a blinded expert in BPH histopathology (D.W.S.) and an experienced radiologist specializing in prostate imaging (D.N.C.), respectively. Each nodule was assigned a phenotypic score on a 5-point Likert scale (1 = predominantly glandular; 5 = predominantly stromal) by each reviewer. Scores were compared using the sign test and univariate analysis. Signal intensity relative to background transition zone and nodule texture were noted on T2, diffusion-weighted imaging (DWI), and dynamic contrast-enhanced (DCE) imaging sequences. Univariate and multivariate stepwise linear regression analysis were conducted to identify MRI features associated with histology score. All analyses were performed using Statistical Analysis System (version 9.4). Results: A total of 99 prostate nodules in 29 patients were included. Median phenotypic scores by histology and MRI were comparable (2, interquartile range [IQR] 2-3 vs 2, IQR 2-4, respectively; p = 0.63). Histology scores were positively correlated with MRI scores (Pearson's correlation 0.84, p < 0.0001). Multivariate stepwise linear regression analysis showed that low apparent diffusion coefficient (ADC) signal intensity (p < 0.001) and DCE wash-in (p = 0.03) were positively associated with more stromal histology, whereas ADC standard deviation (p = 0.03), DCE wash-out (p = 0.001), and heterogeneous T2 texture (p = 0.003) were associated with more glandular histology. Conclusion: There is a strong correlation between MRI features and the histologic phenotype of BPH nodules. MRI may provide a noninvasive method to determine underlying BPH nodule histology.

MRI Evaluation of Patients Before and After Interventions for Benign Prostatic Hyperplasia: An Update

Transurethral resection of the prostate is the most commonly performed procedure for the management of patients with lower urinary tract symptoms attributed to benign prostatic hyperplasia (BPH). However, in recent years, various minimally invasive surgical therapies have been introduced to treat BPH. These include laser-based procedures such as holmium laser enucleation of the prostate and photoselective vaporization of the prostate as well as thermal ablation procedures such as water vapor thermal therapy (Rezūm), all of which result in volume reduction of periurethral prostatic tissue. In comparison, a permanent metallic device (UroLift) can be implanted to pull open the prostatic urethra without an associated decrease in prostate size, and selective catheter-directed prostate artery embolization results in a global decrease in prostate size. The goal of this article is to familiarize radiologists with the underlying anatomic changes that occur in BPH as visualized on MRI and to describe the appearance of the prostate on MRI performed after these procedures. Complications encountered on imaging after these procedures are also discussed. Although MRI is not currently used in the routine preprocedural evaluation of BPH, emerging data support a role for MRI in predicting postprocedure outcomes.

Surgical techniques to improve continence recovery after robot-assisted radical prostatectomy

Radical prostatectomy directly affects urinary continence dynamics with incontinence being a major factor in patients’ quality of life, social and psychological status. In order to help maintain continence after robot-assisted radical prostatectomy (RARP), a number of surgical techniques have been described. In the present narrative review, we summarize the surgical techniques that have been applied during RARP and their effects on incontinence rates and time to continence recovery.

Surgical techniques to improve continence recovery after robot-assisted radical prostatectomy

Radical prostatectomy directly affects urinary continence dynamics with incontinence being a major factor in patients' quality of life, social and psychological status. In order to help maintain continence after robot-assisted radical prostatectomy (RARP), a number of surgical techniques have been described. In the present narrative review, we summarize the surgical techniques that have been applied during RARP and their effects on incontinence rates and time to continence recovery.

Identifying the relationship between postoperative urinary continence and residual urethra stump measurements in robot assisted radical prostatectomy patients

OBJECTIVE

To investigate the feasibility of urethral stump length and width measurements in recorded videos of robot assisted radical prostatectomy procedures using the Kinovea software and to assess if these measurements could be used as predictors of postoperative urinary continence.

METHODS

Fifty-three patients were selected from an institutional database of 1400 cases and included in the study. All videos were analysed using the computer software 'Kinovea'. All measurements were performed using the inserted bladder catheter as a reference point.

RESULTS

The reference point (bladder catheter) was available in 33 out of 53 patients. The median surgical urethral length (SUL) was significantly higher in the continent group (1050 vs. 1294 mm, p = 0.018). The urethral width measurements did not show a difference between the groups. In order to validate the Kinovea software as an accurate tool for the measurement of the urethral stump length and width results were correlated with the magnetic resonance imaging measurements of the urethra.

CONCLUSIONS

The results of this study showed a significantly longer median SUL incontinent patients.

Intravesical prostatic protrusion may affect early postoperative continence undergoing robot-assisted radical prostatectomy

Background

In this study, we investigated the effect of preoperative prostate morphology, especially intravesical prostatic protrusion (IPP), on continence after robot-assisted radical prostatectomy (RARP).

Methods

Retrospective analysis was applied to patients who underwent RARP between October 2010 and July 2014. The following parameters were assessed in all patients: age, body mass index (BMI), prostate-specific antigen, magnetic resonance imaging and pressure-flow studies findings. The impact of preoperative and intraoperative factors on postoperative urinary incontinence (UI) was assessed using multivariate logistic regression analysis. To evaluate the effects of IPP, the patients were divided into groups according to the IPP length: Group 1, < 5 mm and Group 2, ≥ 5 mm. The International Prostate Symptom Score (IPSS), Overactive Bladder Symptom Score, Quality of Life index and the number of pads used were assessed.

Results

A total of 119 patients were eligible for this study. Multivariate analyses showed that IPP (odds ratio (OR) 1.14, 95% confidence interval (CI) 1.02–1.28, p < 0.05) and nerve-sparing (NS) (OR 0.23, 95% CI 0.18–0.61, p < 0.01) were significant factors related to UI in the first month after RARP. Twelve months after RARP, multivariate analyses revealed that only NS is a factor related to postoperative UI (OR 0.23, 95% CI 0.18–0.61, p < 0.01). The comparison of Groups 1 and 2 indicated significant differences in age (p < 0.01), prostate volume (p < 0.01), total IPSS and voiding symptom score (p < 0.05), compliance (p < 0.01), and detrusor pressure at maximum flow (p < 0.01). Group 1 had a higher continence rate (38.0%) than Group 2 (20.8%) in the first month after RARP (p < 0.05), but the difference was no longer significant from the third month after RARP. The total IPSS and voiding symptom scores were significantly different between the two groups before RARP, however, the significant difference disappeared from the first month after RARP.

Conclusions

The data suggest that IPP affects early postoperative UI. Although NS was strongly involved in UI in the early and later stages after RARP, IPP had no effect on UI in the later stages.

Prostate Benign Diseases

Magnetic resonance imaging (MRI) has been increasingly used in the detection, localization, and staging of prostate cancer. Because of its excellent soft tissue contrast and multiplane imaging, it can be also very useful in the evaluation of benign prostate diseases. Prostatic benign disorders have a high prevalence, vastly represented by benign prostatic hyperplasia and prostatitis. On the contrary, benign prostatic neoplasms are extremely rare, represented by multilocular cystadenoma, leiomyomas, hemangioma, and granular cell tumor, although these uncommon tumors have been most encountered due to widespread use of MRI. Congenital prostatic anomalies are associated with defects in the development of the prostate embryology, including hypoplasia, ectopia, and vascular malformations, abnormalities rarely seen on cross-sectional imaging. Prostatic cysts are the most common development abnormalities and occasionally are related to clinical symptoms, mainly due to infection and hemorrhage. As with prostate cancer, multiparametric MRI is a reliable tool for the diagnosis and management of benign prostatic diseases as well, providing additional information such morphological changes of the prostate, more accurate prostatic measurements, and functional characteristics of nonmalignant prostatic lesions. In this review, we discuss MRI findings of these benign prostatic diseases.

Precision and accuracy of magnetic resonance imaging for lobar classification of benign prostatic hyperplasia

PURPOSE

To validate the application of a magnetic resonance imaging (MRI)-based lobar classification of benign prostatic hyperplasia (BPH) for use in research and clinical management.

METHODS

Two radiologists with 5 and 11 years post-fellowship experience were trained in the lobar classification of BPH using an internally developed atlas of prostate anatomy with example MRI images edited by a third senior radiologist designated as the "administrator" of the study. A study population of 140 patients referred to a tertiary academic medical center with known or suspected prostate cancer was selected by the administrator to test the interrater reliability (IRR; precision) of the classification as well as accuracy of the two readers compared to the administrator as the "gold" standard. The intrarater reliability of repeat readings of the administrator was also examined. Percentage of agreement, proportion of agreement, and Cohen's κ were applied. This was a retrospective IRB-approved study.

RESULTS

IRR (precision) between the two interpreting radiologists was 64% agreement, corresponding to unweighted κ of 0.52. Composite proportion of agreement across all BPH types (categories) for interpreting radiologists was 0.67. Observer accuracy was 62% agreement, unweighted κ 0.49, for observer 1 and 67%, unweighted κ 0.58, for observer 2. Intrarater reliability for the administrator was 87% agreement, unweighted κ 0.81 with composite proportion of agreement across all categories of 0.87.

CONCLUSIONS

MRI lobar classification of BPH is a reproducible and reliable tool for research and clinical applications.

Intravesical prostatic protrusion is not always the same shape: Evaluation by preoperative cystoscopy and outcome in HoLEP

AIMS

To examine how morphological differences in intravesical prostatic protrusion (IPP) predict outcome of Holmium laser enucleation of prostate (HoLEP) treatment.

METHODS

We analyzed 173 patients who had undergone HoLEP in our hospital. The protrusion shape was evaluated by outpatient preoperative flexible cystoscopy and classified into five groups: A, no protrusion; B, middle lobe only; C, unilateral lobe only; D, bilateral lobes; and E, B + C or B + D. Paired-match analysis that adjusted for preoperative International Prostate Symptom Score (IPSS) voiding/storage subscores and IPP was performed between the group with middle lobe protrusion (B + E) and the group without it (C + D).

RESULTS

Type A prostate shape was found in 23 patients, type B in 14, type C in 31, type D in 71, and type E in 34. Groups with middle lobe protrusion (B and E) had better changes in the total IPSS (P < 0.05) and the IPSS storage subscore (P < 0.01). Pair matching identified 37 patients each with or without middle lobe protrusion. The group with middle lobe protrusion had significantly more improved total IPSS (-17.5 ± 7.5 vs -13.5 ± 8.3, P < 0.05) and IPSS storage subscore (-6.9 ± 3.4 vs -4.8 ± 3.3, P < 0.05) than did those without middle lobe protrusion.

CONCLUSIONS

Patients with middle lobe protrusion had greater IPSS improvement after HoLEP than those having comparable-length IPP but without middle lobe protrusion. IPP is not always the same shape and should be clinically divided into at least two groups.

Investigational procedures in benign prostatic hypertrophy

PURPOSE OF REVIEW

As benign prostatic hypertrophy (BPH) becomes a more common disease, there has been a dramatic rise in the number of investigational procedures being developed to manage it. We seek to present an overview of the most recently developed treatments and present clinical data related to application wherever available.

RECENT FINDINGS

As a greater number of treatments become available for BPH, improved diagnostic testing could prove beneficial in helping guide patient selection. Efforts are underway to identify serum biomarkers associated with BPH as well as new classifications strategies, specifically with MRI, to determine both the anatomy of BPH as well as its histologic distribution. Outpatient-based procedures for BPH currently being developed include the temporary implantable nitinol device as well as intraprostatic injections such as Botox and PRX302. Aquablation is a novel technique that uses robotically guided high-pressured saline to ablate prostate tissue. Early data suggests noninferiority compared with TURP. Finally, efforts are underway to apply robotics to BPH with the advent of a robotic transurethral platform being designed for prostate enucleation.

SUMMARY

Many new techniques are poised to be introduced to the BPH market over the coming years. The unique risk/benefit profiles as well as associated clinical outcomes of each will need to be studied in detail in order to help identify proper roles in the management of patients with symptomatic disease.