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.

External validation of the Rotterdam prostate cancer risk calculator within a high-risk Dutch clinical cohort.

PURPOSE: This study aims to externally validate the Rotterdam Prostate Cancer Risk Calculator (RPCRC)-3/4 and RPCRC-MRI within a Dutch clinical cohort. METHODS: Men subjected to prostate biopsies, between 2018 and 2021, due to a clinical suspicion of prostate cancer (PCa) were retrospectively included. The performance of the RPCRC-3/4 and RPCRC-MRI was analyzed in terms of discrimination, calibration and net benefit. In addition, the need for recalibration and adjustment of risk thresholds for referral was investigated. Clinically significant (cs) PCa was defined as Gleason score ≥ 3 + 4. RESULTS: A total of 1575 men were included in the analysis. PCa was diagnosed in 63.2% (996/1575) of men and csPCa in 41.7% (656/1575) of men. Use of the RPCRC-3/4 could have prevented 37.3% (587/1575) of all MRIs within this cohort, thereby missing 18.3% (120/656) of csPCa diagnoses. After recalibration and adjustment of risk thresholds to 20% for PCa and 10% for csPCa, use of the recalibrated RPCRC-3/4 could have prevented 15.1% (238/1575) of all MRIs, resulting in 5.3% (35/656) of csPCa diagnoses being missed. The performance of the RPCRC-MRI was good; use of this risk calculator could have prevented 10.7% (169/1575) of all biopsies, resulting in 1.2% (8/656) of csPCa diagnoses being missed. CONCLUSION: The RPCRC-3/4 underestimates the probability of having csPCa within this Dutch clinical cohort, resulting in significant numbers of csPCa diagnoses being missed. For optimal performance of a risk calculator in a specific cohort, evaluation of its performance within the population under study is essential.

A standardized method to measure the membranous urethral length (MUL) on MRI of the prostate with high inter- and intra-observer agreement.

OBJECTIVES: The membranous urethral length (MUL), defined as the length between the apex and penile base as measured on preoperative prostate magnetic resonance imaging (MRI), is an important predictor for urinary incontinence after radical prostatectomy. Literature on inter- and intra - observer agreement of MUL measurement is limited. We studied the inter- and intra-observer agreement between radiologists using a well-defined method to measure the MUL on the prostate MRI. METHODS: Prostate cancer patients underwent a preoperative MRI and robot-assisted radical prostatectomy (RARP) at one high-volume RARP center. MUL measurement was based on well-defined landmarks on sagittal T2-weighted (anatomical) images. Three radiologists independently performed MUL measurements retrospectively in 106 patients blinded to themselves, to each other, and to clinical outcomes. The inter- and intra-observer agreement of MUL measurement between the radiologists were calculated, expressed as intra-class correlation coefficient (ICC). RESULTS: The initial inter-observer agreement was ICC 0.63; 95% confidence interval (CI) 0.28-0.81. Radiologist 3 measured the MUL mean 3.9 mm (SD 3.3) longer than the other readers, interpreting the caudal point of the MUL (penile base) differently. After discussion on the correct anatomical definition, radiologist 3 re-assessed all scans, which resulted in a high inter-observer agreement (ICC 0.84; 95% CI 0.66-0.91). After a subsequent reading by radiologists 1 and 2, the intra-observer agreements were ICC 0.93; 95% CI 0.89-0.96, and ICC 0.98; 95% CI 0.97-0.98, respectively. Limitation is the monocenter design. CONCLUSIONS: The MUL can be measured reliably with high agreement among radiologists. KEY POINTS: • After discussion on the correct anatomical definition, the inter- and intra - observer agreements of membranous urethral length (MUL) measurement on magnetic resonance imaging (MRI) were high. • A reproducible method to measure the MUL can improve the clinical usefulness of prediction models for urinary continence after RARP which may benefit patient counselling.

3D-Reconstructed Contact Surface Area and Tumour Volume on Magnetic Resonance Imaging Improve the Prediction of Extraprostatic Extension of Prostate Cancer.

This study is to determine whether the volume and contact surface area (CSA) of a tumour with an adjacent prostate capsule on MRI in a three-dimensional (3D) model that can predict side-specific extraprostatic extension (EPE) at radical prostatectomy (RP). Patients with localised prostate cancer (PCa) who underwent robot-assisted RP between July 2015 and March 2021 were included in this retrospective study. MRI-based 3D prostate models incorporating the PCa volume and location were reconstructed. The tumour volume and surface variables were extracted. For the prostate-to-tumour and tumour-to-prostate CSAs, the areas in which the distances were ≤ 1, ≤ 2, ≤ 3, ≤ 4, and ≤ 5 mm were defined, and their surface (cm2) were determined. Differences in prostate sides with and without pathological EPE were analysed. Multivariable logistic regression analysis to find independent predictors of EPE. Overall, 75/302 (25%) prostate sides showed pathological EPE. Prostate sides with EPE had higher cT-stage, higher PSA density, higher percentage of positive biopsy cores, higher biopsy Gleason scores, higher radiological tumour stage, larger tumour volumes, larger prostate CSA, and larger tumour CSA (all p < 0.001). Multivariable logistic regression analysis showed that the radiological tumour stage (p = 0.001), tumour volume (p < 0.001), prostate CSA (p < 0.001), and tumour CSA (p ≤ 0.001) were independent predictors of pathological EPE. A 3D reconstruction of tumour locations in the prostate improves prediction of extraprostatic extension. Tumours with a higher 3D-reconstructed volume, a higher surface area of tumour in contact with the prostate capsule, and higher surface area of prostate capsule in contact with the tumour are at increased risk of side-specific extraprostatic extension.

Standardised uptake values as determined on prostate-specific membrane antigen positron emission tomography/computed tomography is associated with oncological outcomes in patients with prostate cancer.

OBJECTIVES: To investigate the association between intraprostatic, intratumoral maximum standardised uptake values (SUVmax ) on prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) in patients with prostate cancer (PCa) prior to robot-assisted radical prostatectomy (RARP) and pathology outcomes, including pathological International Society of Urological Pathology score (pISUP) and lymph node (LN) status (pN0/pN1). PATIENTS AND METHODS: A bi-centric, secondary analysis of two previous, prospective cohort studies was performed in 318 patients with biopsy confirmed PCa and who were scheduled for RARP. Before surgery, patients received a PSMA PET/CT with either 68 Ga-PSMA-11 (59% of the patients) or 18 F-PSMA (DCFPyL; 41%) as radiotracer. PET/CT images were analysed both visually and semi-quantitatively by measuring the SUVmax of the most intense suspect lesion in the prostate. The association between the SUVmax of the primary tumour and pre- and postoperative variables was analysed. RESULTS: The SUVmax was associated with clinical and biopsy preoperative variables, as well as with pISUP score and pathological tumour stage. Patients with a pISUP of ≤2 showed significantly lower SUVmax compared to patients with a pISUP of >2 for both tracers (SUVmax18 F-PSMA: median 5.1 vs 9.6, P = 0.002; SUVmax68 Ga-PSMA-11: 6.6 vs 8.6, P = 0.003). Moreover, patients with pN1 had significantly higher median SUVmax than those with pN0/pNx for both tracers (SUVmax18 F-PSMA: 7.9 vs 12.3, P = 0.04; SUVmax68 Ga-PSMA-11: 7.6 vs 12.0, P < 0.001). On multivariable logistic regression analysis, the intraprostatic SUVmax was an independent predictor of pN1 for both 68 Ga-PSMA-11 (per doubling: odds ratio [OR] 1.96, 95% confidence interval [CI] 1.27-3.01)) and 18 F-PSMA (per doubling: OR 1.79, 95% CI 1.06-3.03). CONCLUSION: Intraprostatic, intratumoral PSMA intensity on PET/CT, as semi-quantitatively expressed by SUVmax , may be a valuable innovative biomarker in patients with localised PCa, as it is highly associated with known conventional prognostic factors, such as pISUP and LN status.

Intraoperative Strategies to Reduce Catheter-Related Bladder Discomfort in the Early Postoperative Period after Robot-Assisted Radical Prostatectomy.

PURPOSE: Catheter-related bladder discomfort occurs in up to 63% of patients following robot-assisted radical prostatectomy. The optimal intraoperative anesthesia regime to prevent patients from catheter-related bladder discomfort is unknown. MATERIALS AND METHODS: A prospective cohort analysis was conducted. Patients with biopsy-proven prostate cancer selected for robot-assisted radical prostatectomy were included between January 2017 and April 2020 from a high volume prostate cancer center. Eight different treatment regimens were compared, ie a combination of general anesthesia and a transversus abdominis plane block with either an additional dose of clonidine or an additional dose of ketamine, or perivesical infiltrations (with 20 ml ropivacaine), or periurethral infiltrations (with ropivacaine); or a dorsal penile nerve block (with 20 ml ropivacaine). Multiple logistic regression and linear mixed models were used to analyze differences in catheter-related bladder discomfort and pain (0-10) at the postoperative recovery unit between the treatment protocols. RESULTS: Of the 391 patients included, those with a combination transversus abdominis plane block, perivesical and periurethral block with ropivacaine had the lowest incidence of catheter-related bladder discomfort, clinically relevant and statistically significantly lower compared to our baseline protocol (transversus abdominis plane block only), ie 36% vs 70%, p=0.001. Overall, patients who were treated with periurethral and/or perivesical infiltrations reported a statistically significantly lower incidence of catheter-related bladder discomfort compared to patients who did not receive this local infiltration (46.5% vs 60.7%, p=0.001). CONCLUSIONS: Perivesical and periurethral injections with ropivacaine have the potential to reduce the incidence of early postoperative catheter-related bladder discomfort by up to 49%. Further randomized studies are necessary to determine the optimal treatment regime to prevent early postoperative catheter-related bladder discomfort.

Patient-Reported Outcomes After Genital Gender-Affirming Surgery With Versus Without Urethral Lengthening in Transgender Men.

BACKGROUND: In our institution, genital Gender-Affirming Surgery (gGAS;phalloplasty or metoidioplasty) in transgender men is offered with or without Urethral Lengthening (UL). AIM: The aim of this cross-sectional and retrospective study was to assess the effect of gGAS with or without UL on several Patient-Reported Outcomes (PROs), and to identify predictors of overall patient satisfaction at follow-up. METHODS: A self-constructed Patient-Reported Outcome Measure (PROM) was sent to transgender men who were ≥1 year after gGAS. The survey comprises 25 questions divided into 5 domains: type of surgery, satisfaction with the appearance and functionality, quality of life, feelings of masculinity, and sexuality. OUTCOMES: Answers to the survey were compared between groups, and a linear regression analysis was conducted to identify predictors of overall patient satisfaction. RESULTS: Of 154 eligible transgender men, the PROM was sent to 118 (77%) willing to participate, and 102 (66%) completed the survey. The majority previously underwent phalloplasty (n = 74;73%) compared to metoidioplasty (n = 28;27%). Urethral Lengthening was performed in 56/102 (55%) participants, 51/74 (69%) in phalloplasty, 5/28 (18%) in metoidioplasty. The mean number of complications and reoperations was significantly higher in the UL group (2.7vs1 and 1.6vs0.4 respectively, both P < .001). Most participants were satisfied to very satisfied with life (75%), the appearance (66%), voiding (59%), the effect of surgery on masculinity (82%), and confirmed that the end surgical result matched their expectations (61%), independently of UL. Lowest scores in satisfaction were observed for the sexual functioning of the neophallus, with 34% satisfied to very satisfied participants. Both satisfaction with the appearance of the neophallus (P < .001) and with voiding (P = .02) were positive predictors of overall patient satisfaction at follow-up, in contrast to the complication and reoperation rate postoperatively (P = .48 and P = .95 respectively). CLINICAL IMPLICATIONS: Transgender men choosing for gGAS with or without UL can be adequately informed on PROs regarding type of surgery, satisfaction with the appearance and functionality, quality of life, feelings of masculinity, and sexuality. STRENGTHS & LIMITATIONS: Study strengths comprise the relatively large cohort, long duration of follow-up, completeness of the data, and innovativeness of the studied outcomes. Limitations are the cross-sectional and retrospective design, possible participation bias and non-validated survey. CONCLUSION: No significant differences in several PROs were observed between participants who chose gGAS with or without UL in this retrospective study. Additionally, according to this study, satisfaction with the appearance of the neophallus and with voiding were positive predictors of overall patient satisfaction at follow-up. de Rooij FPW, van de Grift TC, Veerman H, et al. Patient-Reported Outcomes After Genital Gender-Affirming Surgery With Versus Without Urethral Lengthening in Transgender Men. J Sex Med 2020;18:974-981.

Individual risk prediction of urinary incontinence after prostatectomy and impact on treatment choice in patients with localized prostate cancer.

AIMS: Individualized information about the risk of incontinence after prostatectomy could help patients in shared decision-making. METHODS: We compared a historical control cohort (n = 254; between June 2016 and 2017) that received standardized information about the risk of incontinence after robot-assisted radical prostatectomy (RARP) with a prospective patient cohort (n = 254; between June 2017 and May 2018) that received individualized information of the chance of recovery of incontinence within 6 months postoperatively based on the continence prediction tool (CPRED). We measured switch in treatment choice, health-related quality of life (QoL) in both cohorts and the accuracy of the CPRED tool. RESULTS: Patients in the individualized information group with RARP as initial preference switched more often to another treatment than patients who received standardized information (16% vs. 5%; p = 0.001). Patients in the individualized information group with a high risk of incontinence and with RARP as initial preference switched more often to other treatments than patients in intermediate/low risk of incontinence (35% vs. 9.8%; p = 0.001). Patients with a low risk of incontinence choosing RARP after individualized information were less likely to use more than one diaper a day at any time postoperative (p = 0.001) compared to men with an intermediate/high incontinence risk. Overall QoL was worse in patients with incontinence than patients with continence 6 and 12 months after RARP (respectively; p < 0.0001 and p = 0.007). CONCLUSION: Personalized information about the risk of incontinence after RARP makes more patients reconsidering their initial treatment preference. The CPRED correlated strongly with continence outcome after RARP and is a useful tool for shared decision-making.

The Impact of Omitting Contralateral Systematic Biopsy on the Surgical Planning of Patients with a Unilateral Suspicious Lesion on Magnetic Resonance Imaging Undergoing Robot-assisted Radical Prostatectomy for Prostate Cancer.

Background and objective: A combined approach of magnetic resonance imaging (MRI)-targeted biopsy (TBx) and bilateral systematic biopsy (SBx) is advised in patients who have an increased risk of prostate cancer (PCa). The diagnostic gain of SBx in detecting PCa for treatment planning of patients undergoing robot-assisted radical prostatectomy (RARP) is unknown. This study aims to determine the impact of omitting contralateral SBx on the surgical planning of patients undergoing RARP in terms of nerve-sparing surgery (NSS) and extended pelvic lymph node dissection (ePLND). Methods: Case files from 80 men with biopsy-proven PCa were studied. All men had a unilateral suspicious lesion on MRI, and underwent TBx and bilateral SBx. Case files were presented to five urologists for the surgical planning of RARP. Each case file was presented randomly using two different sets of information: (1) results of TBx + bilateral SBx, and (2) results of TBx + ipsilateral SBx. The urologists assessed whether they would perform NSS and/or ePLND. Key findings and limitations: A change in the surgical plan concerning NSS on the contralateral side was observed in 9.0% (95% confidence interval [CI] 6.4-12.2) of cases. Additionally, the indication for ePLND changed in 5.3% (95% CI 3.3-7.9) of cases. Interobserver agreement based on Fleiss' kappa changed from 0.44 to 0.15 for the indication of NSS and from 0.84 to 0.83 for the indication of ePLND. Conclusions and clinical implications: In our series, the diagnostic information obtained from contralateral SBx has limited impact on the surgical planning of patients with a unilateral suspicious lesion on MRI scheduled to undergo RARP. Patient summary: In patients with one-sided prostate cancer on magnetic resonance imaging, omitting biopsies on the other side rarely changed the surgical plan with respect to nerve-sparing surgery and the indication to perform extended lymph node dissection.

A Systematic Review on the Impact of Quality Assurance Programs on Outcomes after Radical Prostatectomy.

BACKGROUND AND OBJECTIVE: The implementation of quality assurance programs (QAPs) within urological practice has gained prominence; yet, their impact on outcomes after radical prostatectomy (RP) remains uncertain. This paper aims to systematically review the current literature regarding the implementation of QAPs and their impact on outcomes after robot-assisted RP, laparoscopic RP, and open prostatectomy, collectively referred to as RP. METHODS: A systematic Embase, Medline (OvidSP), and Scopus search was conducted, according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) process, on January 12, 2024. Studies were identified and included if these covered implementation of QAPs and their impact on outcomes after RP. QAPs were defined as any intervention seeking quality improvement through critically reviewing, analyzing, and discussing outcomes. Included studies were assessed critically using the Risk of Bias in Nonrandomized Studies of Interventions (ROBINS-I) tool, with results summarized narratively. KEY FINDINGS AND LIMITATIONS: Ten included studies revealed two methodological strategies: periodic performance feedback and surgical video assessments. Despite conceptual variability, QAPs improved outcomes consistently (ie, surgical margins, urine continence, erectile function, and hospital readmissions). Of the two strategies, video assessments better identified suboptimal surgical practice and technical errors. Although the extent of quality improvements did not appear to correlate with the frequency of QAPs, there was an apparent correlation with whether or not outcomes were evaluated collectively. CONCLUSIONS AND CLINICAL IMPLICATIONS: Current findings suggest that QAPs have a positive impact on outcomes after RP. Caution in interpretation due to limited data is advised. More extensive research is required to explore how conceptual differences impact the extent of quality improvements. PATIENT SUMMARY: In this paper, we review the available scientific literature regarding the implementation of quality assurance programs and their impact on outcomes after radical prostatectomy. The included studies offered substantial support for the implementation of quality assurance programs as an incentive to improve the quality of care continuously.

Higher Preoperative Maximum Standardised Uptake Values (SUVmax) Are Associated with Higher Biochemical Recurrence Rates after Robot-Assisted Radical Prostatectomy for [68Ga]Ga-PSMA-11 and [18F]DCFPyL Positron Emission Tomography/Computed Tomography.

This study aimed to investigate the association between the 68Ga- or 18F-radiolabeled prostate-specific membrane antigen (PSMA) tracer expression, represented by the maximum standardised uptake value (SUVmax) of the dominant intraprostatic lesion, and biochemical recurrence (BCR) in primary prostate cancer (PCa) patients prior to robot-assisted radical prostatectomy (RARP). This was a retrospective, multi-centre cohort study of 446 patients who underwent [68Ga]Ga-PSMA-11 (n = 238) or [18F]DCFPyL (n = 206) Positron Emission Tomography/Computed Tomography (PET/CT) imaging prior to RARP. SUVmax was measured in the dominant intraprostatic PCa lesions. [18F]DCFPyL patients were scanned 60 ([18F]DCFPyL-60; n = 106) or 120 ([18F]DCFPyL-120; n = 120) minutes post-injection of a radiotracer and were analysed separately. To normalise the data, SUVmax was log transformed for further analyses. During a median follow-up of 24 months, 141 (30.4%) patients experienced BCR. Log2SUVmax was a significant predictor for BCR (p < 0.001). In the multivariable analysis accounting for these preoperative variables: initial prostate-specific antigen (PSA), radiologic tumour stage (mT), the biopsy International Society of Urological Pathology grade group (bISUP) and the prostate imaging and reporting data system (PI-RADS), Log2SUVmax was found to be an independent predictor for BCR in [68Ga]Ga-PSMA-11 (HR 1.32, p = 0.04) and [18F]DCFPyL-120 PET/CT scans (HR 1.55, p = 0.04), but not in [18F]DCFPyL-60 ones (HR 0.92, p = 0.72). The PSMA expression of the dominant intraprostatic lesion proved to be an independent predictor for BCR in patients with primary PCa who underwent [68Ga]Ga-PSMA-11 or [18F]DCFPyL-120 PET/CT scans, but not in those who underwent [18F]DCFPyL-60 PET/CT scans.

Prostate MRI for Improving Personalized Risk Prediction of Incontinence and Surgical Planning: The Role of Membranous Urethral Length Measurements and the Use of 3D Models.

Prostate MRI has an important role in prostate cancer diagnosis and treatment, including detection, the targeting of prostate biopsies, staging and guiding radiotherapy and active surveillance. However, there are other ''less well-known'' applications which are being studied and frequently used in our highly specialized medical center. In this review, we focus on two research topics that lie within the expertise of this study group: (1) anatomical parameters predicting the risk of urinary incontinence after radical prostatectomy, allowing more personalized shared decision-making, with special emphasis on the membranous urethral length (MUL); (2) the use of three-dimensional models to help the surgical planning. These models may be used for training, patient counselling, personalized estimation of nerve sparing and extracapsular extension and may help to achieve negative surgical margins and undetectable postoperative PSA values.

Identifying Patients in Whom the Follow-Up Scheme after Robot-Assisted Radical Prostatectomy Could Be Optimized in the First Year after Surgery: Reducing Healthcare Burden.

BACKGROUND: The currently advised follow-up scheme of PSA testing after robot-assisted radical prostatectomy (RARP) is strict and might pose a burden to our healthcare system. We aimed to optimize the 1-year follow-up scheme for patients who undergo RARP. METHODS: All patients with histologically-proven prostate cancer (PCa) who underwent RARP between 2018 and August 2022 in the Prostate Cancer Network in the Netherlands were retrospectively evaluated. We excluded patients who underwent salvage RARP and patients who had <1 year of PSA follow-up. Postoperative PSA values were collected. Biochemical persistence (BCP) was defined as PSA level >0.10 ng/mL at 0-4 months after RARP, whereas biochemical recurrence (BCR) was defined as PSA level >0.2 ng/mL at any time point after RARP. We aimed to identify a group of patients who had a very low risk of BCR at different time points after surgery. RESULTS: Of all 1155 patients, BCP was observed in 151 (13%), of whom 79 (6.8%) had PSA ≥ 0.2 ng/mL. BCR further developed in 51 (4.7%) and 37 (3.4%) patients at 5-8 and 9-12 months after RARP, respectively. In 12 patients, BCR was found at 5-8 months after RARP in the absence of BCP. These patients represented 1.2% (12/1004) of the entire group. In other words, 98.8% (992/1004) of patients who had an unmeasurable PSA level at 0-4 months after RARP also had an unmeasurable PSA level 5-8 months after surgery. Limitations are the retrospective design and incomplete follow-up. CONCLUSIONS: Patients with an unmeasurable PSA level at 3-4 months after RARP may not need to be retested until 12 months of follow-up, as almost 100% of patients will not have the biochemically recurrent disease at 5-8 months of follow-up. This will reduce PSA testing substantially at the cost of hardly any missed patients with recurrent disease.

Development and clinical applicability of MRI-based 3D prostate models in the planning of nerve-sparing robot-assisted radical prostatectomy.

The interpretation of conventional MRI may be limited by the two-dimensional presentation of the images. To develop patient-specific MRI prostate-based virtual and three-dimensional (3D)-printed models. To assess the association between 3D imaging and the pathological outcome of RARP specimen. To assess the clinical applicability of 3D models to guide nerve-sparing robot-assisted radical prostatectomy (RARP). We created virtual 3D and 3D-printed 3D models of 20 prostate cancer patients retrospectively. A comparison was made between conventional MRI and 3D-reconstructed images. The concordance between tumour lesion location in 3D models and pathology reporting of RARP specimens was assessed. Seven urologists assessed the side-specific extent of nerve-sparing based on (1) conventional MR images, (2) virtual 3D models, and (3) 3D-printed models. Clinically relevant changes in nerve-sparing and the absolute agreement between observers was analyzed using the Chi-square test and intra-class correlation coefficient (ICC). The index lesion was correctly visualized in 19/20 (95%) 3D models and the expected location of extraprostatic extension was correctly visualized in all 3D models. Clinically relevant changes in the planned extent of nerve-sparing between MRI and virtual 3D models and MRI and 3D-printed models were found in 25% and 26%. The ICC of the planned extent of nerve-sparing between urologists was 0.40 (95% CI 0.28-0.55) for conventional MRI, 0.52 (95% CI 0.39-0.66) for virtual 3D models and 0.58 (95% CI 0.45-0.71) for 3D-printed models. 3D models of the MRI prostate to guide RARP could aid urologists in the planning of nerve-sparing surgery as shown by a higher inter-observer agreement.