Digital Frozen Sections with Fluorescence Confocal Microscopy During Robot-assisted Radical Prostatectomy: Surgical Technique

Neurovascular structure-adjacent frozen-section examination (NeuroSAFE) during robot-assisted radical prostatectomy: a systematic review and meta-analysis of comparative studies

BACKGROUND

To compare surgical, pathological, and functional outcomes of patients undergoing NeuroSAFE-guided RARP vs. RARP alone.

METHODS

In February 2024, a literature search and assessment was conducted through PubMed®, Scopus®, and Web of Science™, to retrieve data of men with PCa (P) undergoing RARP with NeuroSAFE (I) versus RARP without NeuroSAFE (C) to evaluate surgical, pathological, oncological, and functional outcomes (O), across retrospective and/or prospective comparative studies (Studies). Surgical (operative time [OT], number of nerve-sparing [NS] RARP, number of secondary resections after NeuroSAFE), pathological (PSM), oncological (biochemical recurrence [BCR]), and functional (postoperative continence and sexual function recovery) outcomes were analyzed, using weighted mean difference (WMD) for continuous variables and odd ratio (OR) for dichotomous variables.

RESULTS

Overall, seven studies met the inclusion criteria (one randomized clinical trial, one prospective non-randomized trial and five retrospective studies) and were eligible for SR and MA. A total of 4,207 patients were included in the MA, with 2247 patients (53%) undergoing RARP with the addition of NeuroSAFE, and 1 960 (47%) receiving RARP alone. The addition of NeuroSAFE enhanced the likelihood of receiving a nerve-sparing (NS) RARP (OR 5.49, 95% CI 2.48-12.12, I2 = 72%). In the NeuroSAFE cohort, a statistically significant reduction in the likelihood of PSM at final pathology (OR 0.55, 95% CI 0.39-0.79, I2 = 73%) was observed. Similarly, a reduced likelihood of BCR favoring the NeuroSAFE was obtained (OR 0.47, 95% CI 0.35-0.62, I2 = 0%). At 12-month postoperatively, NeuroSAFE led to a significantly higher likelihood of being pad-free (OR 2.01, 95% CI 1.25-3.25, I2 = 0%), and of erectile function recovery (OR 3.50, 95% CI 2.34-5.23, I2 = 0%).

CONCLUSION

Available evidence suggests that NeuroSAFE might represent a histologically based approach to NVB preservation, broadening the indications of NS RARP, reducing the likelihood of PSM and subsequent BCR. In addition, it might translate into better functional postoperative outcomes. However, the current body of evidence is mostly derived from non-randomized studies with a high risk of bias.

Intraoperative margin assessment during radical prostatectomy: is microscopy frozen in time or ready for digital defrost?

Intraoperative frozen section (IFS) is used with the intention to improve functional and oncological outcomes for patients undergoing radical prostatectomy (RP). High resource requirements of IFS techniques such as NeuroSAFE may preclude widespread adoption, even if there are benefits to patients. Recent advances in fresh-tissue microscopic digital imaging technologies may offer an attractive alternative, and there is a growing body of evidence regarding these technologies. In this narrative review, we discuss some of the familiar limitations of IFS and compare these to the attractive counterpoints of modern digital imaging technologies such as the speed and ease of image generation, the locality of equipment within (or near) the operating room, the ability to maintain tissue integrity, and digital transfer of images. Confocal laser microscopy (CLM) is the modality most frequently reported in the literature for margin assessment during RP. We discuss several imitations and obstacles to widespread dissemination of digital imaging technologies. Among these, we consider how the 'en-face' margin perspective will challenge urologists and pathologists to understand afresh the meaning of positive margin significance. As a part of this, discussions on how to describe, categorize, react to, and evaluate these technologies are needed to improve patient outcomes. Limitations of this review include its narrative structure and that the evidence base in this field is relatively immature but developing at pace.

Clinical risk prediction model and external validation of positive surgical margin in laparoscopic radical prostatectomy based on MRI lesion location

OBJECTIVE

To clarify the composition of lesions in different magnetic resonance imaging (MRI) partitions of positive surgical margins (PSM) after laparoscopic radical prostatectomy, explore the influence of lesion location on PSM, and construct a clinical prediction model to predict the risk of PSM.

MATERIALS AND METHODS

This retrospective cohort study included 309 patients who underwent laparoscopic radical prostatectomy from 2018 to 2021 in our center was performed. 129 patients who met the same criteria from January to September 2022 were external validation cohorts.

RESULTS

The incidence of PSM in transition zone (TZ) lesions was higher than that in peripheral zone (PZ) lesions. The incidence of PSM in the middle PZ was lower than that in other regions. Prostate specific antigen (PSA), clinical T-stage, the number of positive cores, international society of urological pathology (ISUP) grade (biopsy), MRI lesion location, extracapsular extension, seminal vesicle invasion (SVI), pseudo-capsule invasion (PCI), long diameter of lesions, lesion volume, lesion volume ratio, PSA density were related to PSM. MRI lesion location and PCI were independent risk factors for PSM. Least absolute shrinkage and selection operator (LASSO) regression was used to construct a clinical prediction model for PSM, including five variables: the number of positive cores, SVI, MRI lesion location, long diameter of lesions, and PSA.

CONCLUSION

The positive rate of surgical margin in middle PZ was significantly lower than that in other regions, and MRI lesion location was an independent risk factor for PSM.

Intraoperative technologies to assess margin status during radical prostatectomy - a narrative review

Positive surgical margin (PSM) is a frequent concern for surgeons performing radical prostatectomy for prostate cancer (PCa). PSM are recognized as risk factors for earlier biochemical recurrence and expose patients to adjuvant or salvage treatments such as external radiotherapy and hormonotherapy. Several strategies have been established to reduce PSM rate, while still allowing safe nerve-sparing surgery. Precise preoperative staging by multiparametric magnetic resonance imaging (mpMRI) and fusion biopsy is recommended to identify suspicious areas of extracapsular extension (ECE) that warrant special attention during dissection. However, even with optimal imaging, ECE can be missed, some cancers are not well defined or visible, and capsular incision during surgery remains an issue. Hence, intraoperative frozen section techniques, such as the neurovascular structure-adjacent frozen section examination (NeuroSAFE) have been developed and lately widely disseminated. The NeuroSAFE technique reduces PSM rate while allowing higher rate of nerve-sparing surgery. However, its use is limited to high volume or expert center because of its high barrier-to-entry in terms of logistics, human resources and expertise, as well as cost. Also, NeuroSAFE is a time-consuming process, even in expert hands. To address these issues, several technologies have been developed for an ex vivo and in vivo use. Ex vivo technology such as fluorescent confocal microscopy and intraoperative PET-CT require the extraction of the specimen for preparation, and digital images acquisition. In vivo technology, such as augmented reality based on mpMRI images and PSMA-fluorescent guided surgery have the advantage to provide an intracorporeal analysis of the completeness of the resection. The current manuscript provides a narrative review of established techniques, and details several new and promising techniques for intraoperative PSM assessment.

Impact of frozen section on long-term outcomes in robot-assisted laparoscopic prostatectomy

OBJECTIVES

To compare 1-year functional and 5-year oncological outcomes of men undergoing robot-assisted laparoscopic prostatectomy (RALP) with neurovascular structure-adjacent frozen-section examination (NeuroSAFE) with those in men undergoing RALP without NeuroSAFE (standard of care [SOC]).

SUBJECTS AND METHODS

Men undergoing RALP in our centre between 1 January 2009 and 30 June 2018 were enrolled from a prospectively maintained database. Patients were excluded if they had undergone preoperative therapy or postoperative adjuvant therapy or were enrolled in clinical trials. Patients were grouped based on use of NeuroSAFE. Follow-up was censored at 5 years. The primary outcome was difference in time to biochemical recurrence (BCR) on multivariable analysis, defined as prostate-specific antigen (PSA) >0.2 ng/L on two consecutive measurements. Secondary outcomes were difference in 1-year erectile dysfunction and incontinence.

RESULTS

In the enrolment period, 1199 consecutive men underwent RALP, of whom 1140 were eligible, including 317 with NeuroSAFE and 823 with SOC. The median PSA follow-up was 60 months in both groups. Rates of 5-year BCR were similar on Kaplan-Meier survival curve analysis (11% vs 11%; P = 0.9), as was time to BCR on multivariable Cox proportional hazards modelling (hazard ratio 1.2; P = 0.6). Compared with the SOC group at 1 year, the NeuroSAFE group had similar unadjusted rates of incontinence (5.1% vs 7.7%) and lower unadjusted impotence (57% vs 80%). On multivariable analysis, NeuroSAFE patients had equivalent risk of incontinence (odds ratio [OR] 0.59, 95% CI 0.17-1.6; P = 0.4) but significantly reduced risk of erectile dysfunction (OR 0.37, 95% CI 0.22-0.60; P < 0.001).

CONCLUSIONS

For men undergoing RALP, compared with SOC, NeuroSAFE patients had equivalent time to BCR and risk of 1-year incontinence, and significantly lower risk of 1-year erectile dysfunction.

Evaluation of margins during radical prostatectomy: confocal microscopy vs frozen section analysis

OBJECTIVES

To test the performance of ex vivo fluorescence confocal microscopy (FCM; Vivascope 2500M-G4), as compared to intra-operative frozen section (IFS) analysis, to evaluate surgical margins during robot-assisted radical prostatectomy (RARP), with final pathology as the reference standard.

METHODS

Overall, 54 margins in 45 patients treated with RARP were analysed with: (1) ex vivo FCM; (2) IFS analysis; and (3) final pathology. FCM margins were evaluated by two different pathologists (experienced [M.I.: 10 years] vs highly experienced [G.R.: >30 years]) as strongly negative, probably negative, doubtful, probably positive, or strongly positive. First, inter-observer agreement (Cohen's κ) between pathologists was tested. Second, we reported the sensitivity, specificity, positive predictive (PPV) and negative predictive value (NPV) of ex vivo FCM. Finally, agreement between ex vivo FCM and IFS analysis (Cohen's κ) was reported. For all analyses, four combinations of FCM results were evaluated.

RESULTS

At ex vivo FCM, the inter-observer agreement between pathologists ranged from moderate (κ = 0.74) to almost perfect (κ = 0.90), according to the four categories of results. Indeed, at ex vivo FCM, the highly experienced pathologist reached the best balance between sensitivity (70.5%) specificity (91.8%), PPV (80.0%) and NPV (87.1%). Conversely, on IFS analysis, the sensitivity, specificity, PPV and NPV were, respectively, 88.2% vs 100% vs 100% vs 94.8%. The agreement between the ex vivo FCM and IFS analyses ranged from moderate (κ = 0.62) to strong (κ = 0.86), according to the four categories of results.

CONCLUSION

Evaluation of prostate margins at ex vivo FCM appears to be feasible and reliable. The agreement between readers encourages its widespread use in daily practice. Nevertheless, as of today, the performance of FCM seems to be sub-par when compared to the established standard of care (IFS analysis).

Ex Vivo Fluorescence Confocal Microscopy for Intraoperative Examinations of Lung Tumors as Alternative to Frozen Sections-A Proof-of-Concept Study

BACKGROUND

Intraoperative frozen sections (FS) are frequently used to establish the diagnosis of lung cancer when preoperative examinations are not conclusive. The downside of FS is its resource-intensive nature and the risk of tissue depletion when small lesions are assessed. Ex vivo fluorescence confocal microscopy (FCM) is a novel microimaging method for loss-free examinations of native materials. We tested its suitability for the intraoperative diagnosis of lung tumors.

METHODS

Samples from 59 lung resection specimens containing 45 carcinomas were examined in the FCM. The diagnostic performance in the evaluation of malignancy and histological typing of lung tumors was evaluated in comparison with FS and the final diagnosis.

RESULTS

A total of 44/45 (98%) carcinomas were correctly identified as malignant in the FCM. A total of 33/44 (75%) carcinomas were correctly subtyped, which was comparable with the results of FS and conventional histology. Our tests documented the excellent visualization of cytological features of normal tissues and tumors. Compared to FS, FCM was technically less demanding and less personnel intensive.

CONCLUSIONS

The ex vivo FCM is a fast, effective, and safe method for diagnosing and subtyping lung cancer and is, therefore, a promising alternative to FS. The method preserves the tissue without loss for subsequent examinations, which is an advantage in the diagnosis of small tumors and for biobanking.

[Fluorescence confocal microscopy-complete digitization of pathology]

BACKGROUND

Fluorescence-based confocal microscopy (FCM) can be used to create virtual H&E sections in real time. So far, FCM has been used in dermato-, uro-, and gynecopathology. FCM allows the creation of a completely digitized frozen section, which could potentially replace conventional frozen sections in the future.

OBJECTIVE

The aim of the current work is to implement FCM technology as a component of fully digitized processes in the pathological workflow. For this purpose, the current use of FCM in liver transplant pathology will be extended to other disciplines such as urology and otorhinolaryngology.

MATERIALS AND METHODS

The FCM technique continues to be used prospectively on native tissue samples from potential donor livers. Conventional frozen sections are used comparatively to virtual FCM scans.

RESULTS

The data show a nearly perfect agreement for the detection of cholangitis, fibrosis, and malignancy, and a high level of agreement for, e.g., macrovesicular steatosis, inflammation, steatohepatitis, and necrosis between virtual FCM scans and conventional routine diagnostic frozen sections.

CONCLUSION

Since the availability of time- and cost-intensive frozen section diagnostics in the context of transplant pathology in continuous operation (24/7) is now only established at very few university centers in Germany due to an increasing shortage of specialists, the use of FCM could be an important building block in the current process leading towards a fully digitized pathology workflow and should thus be extended to various disciplines.

The value of preoperative neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and red blood cell distribution width in predicting positive surgical margin after laparoscopic radical prostatectomy

BACKGROUND

Prostate cancer (PCa) is one of the most common malignant tumors in men, and laparoscopic radical prostatectomy (LRP) is commonly used to treat localized and advanced PCa. Positive surgical margin (PSM) is one of the most frequent problems faced by surgeons.

AIMS

This study aimed to explore the value of the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and red blood cell distribution width (RDW) in predicting PSM after LRP.

METHODS AND RESULTS

Three hundred and twenty patients with PCa were admitted and underwent LRP in Beijing Chaoyang Hospital from January 2017 to June 2023. Patients were randomly divided into a training set (225 cases) and a validation set (95 cases) in a 7:3 ratio. NLR, PLR, and RDW were significantly higher in the PSM group than in the negative surgical margins (NSM) group. In addition, the NLR, PLR, and RDW values correlated with clinical T stage, Gleason score, and seminal vesicle invasion in the PSM group. In training set, ROC curve analysis revealed that the optimal cutoff values of NLR, PLR, and RDW for predicting postoperative PSM in PCa were 2.31, 115.40, and 12.85%, respectively. Multivariate Logistic regression analysis showed NLR and RDW were the clinical independent predictors. The area under the curve (AUC, 0.770, 95% CI 0.709-0.831) for postoperative PSM was the highest when a combination of the three parameters was used, with sensitivity and specificity of 62.5% and 85.2%, respectively. In validation set, the AUC values for NLR, PLR, RDW and the three markers combined were 0.708, 0.675, 0.723, and 0.780, respectively. Correlation analysis showed that in the PSM group, NLR was positively correlated with PLR and RDW, and PLR was positively correlated with RDW. By contrast, in the NSM group, a positive association was only found between NLR and PLR.

CONCLUSIONS

Higher preoperative NLR, PLR, and RDW values were associated with postoperative PSM. Additionally, the three markers combined may be useful to predict PSM.

Accuracy of Ex-vivo Fluorescence Confocal Microscopy in Margin Assessment of Solid Tumors: A Systematic Review

Fluorescence confocal microscopy (FCM) is a novel technology that enables rapid high-resolution digital imaging of non-formalin-fixed tissue specimens and offers real-time positive surgical margin identification. In this systematic review, we evaluated the accuracy metrics of ex vivo FCM for intraoperative margin assessment of different tumor types. A systematic search of MEDLINE via PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, and Scopus was performed for relevant papers (PROSPERO ID: CRD42022372558). We included 14 studies evaluating four types of microscopes in six different tumor types, including breast, prostate, central nervous system, kidney, bladder, and conjunctival tumors. Using the Quality Assessment of Diagnostic Accuracy Studies tool, we identified a high risk of bias in patient selection (21%) and index test (36%) of the included studies. Overall, we found that FCM has good accuracy metrics in all tumor types, with high sensitivity and specificity (>80%) and almost perfect concordance (>90%) against final pathology results. Despite these promising findings, the quality of the available evidence and bias concerns highlight the need for adequately designed studies to further define the role of ex vivo FCM in replacing the frozen section as the tool of choice for intraoperative margin assessment.

Fluorescence confocal microscopy on liver specimens for full digitization of transplant pathology

Fluorescence confocal microscopy (FCM) is a rapidly evolving tool that provides real-time virtual HE images of native tissue. Data about the potential of FCM as an alternative to frozen sections for the evaluation of donor liver specimens are lacking so far. The aim of the current study was to determine the value of FCM in liver specimens according to the criteria of the German Society for Organ Procurement. In this prospective study, conventional histology and FCM scans of 50 liver specimens (60% liver biopsies, 26% surgical specimens, and 14% donor samples) were evaluated according to the German Society for Organ Procurement. A comparison of FCM scans and conventional frozen sections revealed almost perfect levels of agreement for cholangitis (κ = 0.877), fibrosis (κ = 0.843), and malignancy (κ = 0.815). Substantial levels of agreement could be obtained for macrovesicular steatosis (κ = 0.775), inflammation (κ = 0.763), necrosis (κ = 0.643), and steatohepatitis (κ = 0.643). Levels of agreement were moderate for microvesicular steatosis (κ = 0.563). The strength of agreement between frozen sections and FCM was superior to the comparison of conventional HE and FCM imaging. We introduce FCM as a potential alternative to the frozen section that may represent a novel approach to liver transplant pathology where timely feedback is crucial and the deployment of human resources is becoming increasingly difficult.

Biopsy prostate cancer perineural invasion and tumour load are associated with positive posterolateral margins at radical prostatectomy: implications for planning of nerve-sparing surgery

AIMS

Radical prostatectomy (RP) for prostate cancer is frequently complicated by erectile dysfunction and urinary incontinence. However, sparing of the nerve bundles adjacent to the posterolateral sides of the prostate reduces the number of complications at the risk of positive surgical margins. Preoperative selection of men eligible for safe, nerve-sparing surgery is therefore needed. Our aim was to identify pathological factors associated with positive posterolateral surgical margins in men undergoing bilateral nerve-sparing RP.

METHODS AND RESULTS

Prostate cancer patients undergoing RP with standardised intra-operative surgical margin assessment according to the NeuroSAFE technique were included. Preoperative biopsies were reviewed for grade group (GG), cribriform and/or intraductal carcinoma (CR/IDC), perineural invasion (PNI), cumulative tumour length and extraprostatic extension (EPE). Of 624 included patients, 573 (91.8%) received NeuroSAFE bilaterally and 51 (8.2%) unilaterally, resulting in a total of 1197 intraoperative posterolateral surgical margin assessments. Side-specific biopsy findings were correlated to ipsilateral NeuroSAFE outcome. Higher biopsy GG, CR/IDC, PNI, EPE, number of positive biopsies and cumulative tumour length were all associated with positive posterolateral margins. In multivariable bivariate logistic regression, ipsilateral PNI [odds ratio (OR) = 2.98, 95% confidence interval (CI) = 1.62-5.48; P < 0.001] and percentage of positive cores (OR = 1.18, 95% CI = 1.08-1.29; P < 0.001) were significant predictors for a positive posterolateral margin, while GG and CR/IDC were not.

CONCLUSIONS

Ipsilateral PNI and percentage of positive cores were significant predictors for a positive posterolateral surgical margin at RP. Biopsy PNI and tumour volume can therefore support clinical decision-making on the level of nerve-sparing surgery in prostate cancer patients.

Prostate Volume Influence on Postoperative Outcomes for Patients Undergoing RARP: A Monocentric Serial Analysis of 500 Cases

Elevated prostate volume is considered to negatively influence postoperative outcomes after robot-assisted radical prostatectomy (RARP). We aim to investigate the influence of prostate volume on readmissions and complications after RARP. Methods: A total of 500 consecutive patients who underwent RARP between April 2019 and August 2022 were included. Patients were dichotomized into two groups using a prostate volume cut-off of 50 mL (small and normal prostate (SNP) n = 314, 62.8%; large prostate n = 186, 37.2%). Demographic, baseline, and perioperative data were analyzed. The postoperative complications and readmission rates within 90 days after RARP were compared between groups. A univariate linear analysis was performed to investigate the association between prostate volume and other relevant outcomes. Results: Patients with larger prostates had a higher IPSS score, and therefore, more relevant LUTS at the baseline. They had higher ASA scores (p = 0.015). They also had more catheter days (mean 6.6 days for SNP vs. 7.5 days for LP) (p = 0.041). All oncological outcomes were similar between the groups. Although statistical analysis showed no significant difference between the groups (p = 0.062), a trend for minor complications in patients with larger prostates, n = 37/186 (19.8%) for the LP group vs. n = 37/314 (11.7%) in the SNP group, was observed. Namely, acute urinary retention and secondary anastomosis insufficiency. Major complications with an SNP (4.4%) and LP (3.7%) (p = 0.708) and readmissions with an SNP (6.25%) and LP (4.2%) (p = 0.814) were infrequent and distributed equally between the groups. In univariate analysis, prostate volume could solely predict a longer console time (p = 0.005). Conclusions: A higher prostate volume appears to have minimal influence on the perioperative course after RARP. It can prolong catheter days and increase the incidence of minor complications such as acute urinary retention. However, it might predict minor changes in operating time. Yet, prostate volume has less influence on major complications, readmissions, or oncological results.

Real-Time Urethral and Ureteral Assessment during Radical Cystectomy Using Ex-Vivo Optical Imaging: A Novel Technique for the Evaluation of Fresh Unfixed Surgical Margins

Background: Our study aims to assess the feasibility and the reproducibility of fluorescent confocal microscopy (FCM) real-time assessment of urethral and ureteral margins during open radical cystectomy (ORC) for bladder cancer (BCa). Methods: From May 2020 to January 2022, 46 patients underwent ORC with intraoperative FCM evaluation. Each specimen was intraoperatively stained for histopathological analysis using FCM, analyzed as a frozen section (FSA), and sent for traditional H&E examination. Sensitivity, specificity, positive predictive value (PPV), and the negative predictive value (NPV) of FCM and FSA were assessed and compared with H&E for urethral and ureteral margins separately. Results: The agreement was evaluated through Cohen’s κ statistic. Urethral diagnostic agreement between FCM and FSA showed a κ = 0.776 (p < 0.001), while between FCM and H&E, the agreement was κ = 0.691 (p < 0.001). With regard to ureteral margins, an overall agreement of κ = 0.712 (p < 0.001) between FCM and FSA and of κ = 0.481 (p < 0.001) between FCM and H&E was found. Conclusions: FCM proved to be a safe, feasible, and reproducible method for the intraoperative assessment of urethral and ureteral margins during ORC. Compared to standard FSA, FCM showed adequate diagnostic performance in detecting urethral and ureteral malignant involvement.

The NeuroSAFE frozen section technique during radical prostatectomy - Implementation and optimization of technical aspects in a routine pathology workflow

BACKGROUND AND AIMS

In prostate cancer patients, application of the NeuroSAFE frozen section technique during radical prostatectomy has been shown to increase the rate of nerve sparing surgery and to improve functional outcome for the patients. The aim of this study is to report on technical and organizational optimization opportunities of the procedure.

MATERIAL AND METHODS

All patients submitted to bilateral intraoperative frozen section from January 2018 until December 2020 (n = 452) were retrospectively analyzed and parameters such as turnaround time, staff situation in the laboratory and histologic properties of the tumors were assessed.

RESULTS

The median turnaround time per case was 40.3 ( ± 10.5) min. In 2020 the average time needed from accessioning to diagnosis was 38.1 min. Multivariate linear regression suggested that the number of technical assistants/cryotomes (46.1 min vs. 39.13 min; p < 0.001), the place of microscopic examination (43.0 min vs. 38.7 min; p < 0.001) and the presence of a positive margin (38.0 vs. 44.0 min; p < 0.001) were significant influential factors. The turnaround time was independent of the uropathological expertize of the consultant (39.84 min vs. 40.7 min; p = 0.09), the tumor grade (42.3 vs 39.8 min; p = 0.493) and the presence of extraprostatic extension (44.0 vs 39.8 min; p = 0.099).

CONCLUSION

The implementation of simple optimization measures in the workflow as well as structured training of all pathology staff involved in the examination leads to a significant increase in the efficiency of the examination while maintaining the same level of resources. The results could thus be a contribution to the broader application of the procedure.

Rapid On-Site Microscopy and Mapping of Diagnostic Biopsies for See-And-Treat Guidance of Localized Prostate Cancer Therapy

Prostate cancer continues to be the most diagnosed non-skin malignancy in men. While up to one in eight men will be diagnosed in their lifetimes, most diagnoses are not fatal. Better lesion location accuracy combined with emerging localized treatment methods are increasingly being utilized as a treatment option to preserve healthy function in eligible patients. In locating lesions which are generally <2cc within a prostate (average size 45cc), small variance in MRI-determined boundaries, tumoral heterogeneity, patient characteristics including location of lesion and prostatic calcifications, and patient motion during the procedure can inhibit accurate sampling for diagnosis. The locations of biopsies are recorded and are then fully processed by histology and diagnosed via pathology, often days to weeks later. Utilization of real-time feedback could improve accuracy, potentially prevent repeat procedures, and allow patients to undergo treatment of clinically localized disease at earlier stages. Unfortunately, there is currently no reliable real-time feedback process for confirming diagnosis of biopsy samples. We examined the feasibility of implementing structured illumination microscopy (SIM) as a method for on-site diagnostic biopsy imaging to potentially combine the diagnostic and treatment appointments for prostate cancer patients, or to confirm tumoral margins for localized ablation procedures. We imaged biopsies from 39 patients undergoing image-guided diagnostic biopsy using a customized SIM system and a dual-color fluorescent hematoxylin & eosin (H&E) analog. The biopsy images had an average size of 342 megapixels (minimum 78.1, maximum 842) and an average imaging duration of 145 s (minimum 56, maximum 322). Comparison of urologist's suspicion of malignancy based on MRI, to pathologist diagnosis of biopsy images obtained in real time, reveals that real-time biopsy imaging could significantly improve confirmation of malignancy or tumoral margins over medical imaging alone.

NeuroSAFE in radical prostatectomy increases the rate of nerve-sparing surgery without affecting oncological outcome

OBJECTIVES

To investigate the impact of intra-operative neurovascular structure-adjacent frozen-section examination (NeuroSAFE) on the rate of nerve-sparing surgery (NSS) and oncological outcome in a large radical prostatectomy (RP) cohort.

PATIENTS AND METHODS

Between January 2016 and December 2020, 1756 prostate cancer patients underwent robot-assisted RP, of whom 959 (55%) underwent this with NeuroSAFE and 797 (45%) without (control cohort). In cases where NeuroSAFE showed tumour in the margin, a secondary resection was performed. The effect of NeuroSAFE on NSS and positive surgical margin (PSM) status was analysed using logistic regression. Cox regression was used to identify predictors of biochemical recurrence-free survival (BCRFS).

RESULTS AND LIMITATIONS

Patients in the NeuroSAFE cohort had a higher tumour grade (P < 0.001) and clinical stage (P < 0.001) than those in the control cohort. NeuroSAFE enabled more frequent NSS for both pT2 (93% vs 76%; P < 0.001) and pT3 disease (83% vs 55%; P < 0.001). In adjusted analysis, NeuroSAFE resulted in more frequent unilateral (odds ratio [OR] 3.90, 95% confidence interval (CI) 2.90-5.30; P < 0.001) and bilateral (OR 5.22, 95% CI 3.90-6.98; P < 0.001) NSS. While the PSM rate decreased from 51% to 42% in patients with pT3 stage disease (P = 0.031), NeuroSAFE was not an independent predictor of PSM status (OR 0.85, 95% CI 0.68-1.06; P = 0.2) in the entire cohort. Patients who underwent NeuroSAFE had better BCRFS compared to the control cohort (hazard ratio 0.62, 95% CI 0.45-0.84; P = 0.002). This study is limited by its comparison with a historical cohort and lack of functional outcomes.

CONCLUSIONS

NeuroSAFE enables more unilateral and bilateral NSS without negatively affecting surgical margin status and biochemical recurrence. This validation study provides a comprehensive overview of the implementation, evaluation and intra-operative decision making associated with NeuroSAFE in clinical practice.

Digital real-time microscopy of ex-vivo tissues: A novel strategy to control surgical accuracy

Introduction:

Ex-vivo FCM is a novel digital optical technique that provides images of fresh tissues in a real-time fashion with magnification to subcellular details of a flattened unprocessed sample. Digital images are hematoxylin-eosin-like and can be shared and interpreted remotely. In urology, FCM has been successfully applied for prostate tissue interpretation, either during biopsy and radical prostatectomy. Possible applications of FCM may reflect those of frozen section analysis and can be extended to all fields in which the intra-operative microscopical control is advisable.

Materials and methods:

This is an investigative prospective case series that aims to explore FCM feasibility in novel surgical settings and provide a depiction of FCM digital images in those fields. The definite purpose is to check the accuracy of surgical specimen during the following interventions: (a) trans-urethral resection of bladder tumors, to confirm the presence of muscular layer; (b) biopsy of a retroperitoneal mass, to check for the location and quality of cores; (c) training in robotic radical prostatectomy, to control surgical margins after a nerve sparing performed by a trainee. To this aim, we collected FCM images during seven surgical procedures. FCM findings were compared to those from the final histopathological analysis and the agreement was assessed.

Results:

In all cases, FCM digital images were obtained in the OR. FCM was able to confirm the presence of muscular layer in TURB specimen, the presence of lymphomatous tissue, surgical margins at prostate specimen. FCM intra-operative interpretation was consistent with final histopathology in all cases.

Conclusions:

Ex vivo FCM may represent a novel approach to control the quality of specimens, likely to tailor surgical strategy in a real-time fashion. Moreover, digitalization represents a step toward the implementation of telepathology in clinical practice.