Intraoperative frozen section monitoring during nerve-sparing radical prostatectomy: evaluation of partial secondary resection of neurovascular bundles and its effect on oncologic and functional outcome

Nerve-sparing radical prostatectomy using the neurovascular structure-adjacent frozen-section examination (NeuroSAFE): results after 20 years of experience

OBJECTIVES

To evaluate the long-term oncological outcomes and functional results of the neurovascular structure-adjacent frozen-section examination (NeuroSAFE) during nerve-sparing (NS) radical prostatectomy (RP).

MATERIALS AND METHODS

A 10-yr survival analysis on 11069 RPs performed with or without the NeuroSAFE, between January 2002 to June 2011 was carried out. In the NeuroSAFE cohort, the neurovascular structure-adjacent prostatic margins are removed and stained for cryo-sectioning during RP. In case of a PSM, partial or full removal of the neurovascular bundle was performed. The impact of NeuroSAFE on biochemical recurrence-free survival (BFS), salvage radiation therapy-free survival, metastasis-free survival, and prostate cancer-specific survival at 10 years was analyzed. 1-year (1-yr) erectile function (EF), 1-yr, and 2-yr continence rates were assessed in propensity score-based matched cohorts.

RESULTS

Median follow-up was 121 (IQR: 73, 156) months. No differences in BFS between NeuroSAFE and non-NeuroSAFE were recorded (10-yr BFS: NeuroSAFE vs non-Neurosafe, pT2: 81% vs 84%, p = 0.06; pT3a: 58% vs. 63%, p = 0.6; ≥pT3b: 22% vs. 27%, p = 0.99). No differences were found between the two groups in terms of sRFS (pT2: p = 0.1; pT3a: p = 0.4; ≥pT3b: p = 0.4) (Fig. 1B, Table 2), and MTS (pT2: p = 0.3; pT3a: p = 0.6; ≥pT3b: p = 0.9). The NeuroSAFE-navigated patients reported a better 1-yr EF than non-NeuroSAFE (68% vs. 58%, p = 0.02) and no differences in 1-yr and 2-yr continence rates (92.4% vs. 91.8%, and 93.4% vs. 93%, respectively). The main limitation is the retrospective study design.

CONCLUSIONS

While the NeuroSAFE approach did not show significant improvements in long-term oncologic or continence outcomes, it did provide an opportunity for a higher proportion of patients to improve postoperative functional results, possibly through increased nerve-sparing procedures.

3D-printed model for resection of positive surgical margins in robot-assisted prostatectomy

OBJECTIVES

To improve precision of secondary resection (SR) after positive surgical margin (PSM) detection by frozen section (FS) during nerve-sparing (NS) robot-assisted radical prostatectomy (RARP) by employing a personalised three-dimensional (3D)-printed prostate model derived from pelvic magnetic resonance imaging (MRI). This model was used to mark positive surgical margins (PSM) and guide intraoperative SR during NS-RARP.

PATIENTS AND METHODS

Prospective multicentre cohort study with 100 patients undergoing NS-RARP between September 2018 and August 2021. Primary and secondary endpoints were the conversion rate of FS-identified PSM to a tumour-free margin and functional/oncological parameters within a 12-month follow-up, respectively.

RESULTS

A PSM was identified in 23% of cases during FS, with a conversion to negative surgical margins (NSM) in 83% (19/23 cases) by model-guided SR. The tumour detection rate in SR specimens was 39% (nine of 23 cases). Among the 19 patients with converted margins, 18 (95%) achieved undetectable prostate-specific antigen levels 2 months postoperatively, with six (32%) having subsequent biochemical recurrence within 12 months. prostate-specific-membrane-antigen positron emission tomography computed tomography found one local recurrence, and five cases of metastatic disease. In converted patients, the baseline median five-item version of the International Index of Erectile Function score decreased by 16% after 1 year, with no significant difference compared to patients with primarily NSM. Limitations include the absence of a control group, the potential for false-negative FS results and limited accuracy of MRI.

CONCLUSION

The integration of 3D-printed prostate models into NS-RARP has the potential to positively impact surgical outcomes by improving the precision of SR and optimising pathosurgical communication.

Neurovascular Structure-adjacent Frozen-section Examination (NeuroSAFE) During Radical Prostatectomy: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVE

A standardized intraoperative frozen section analysis of the prostate resection margin adjacent to the neurovascular bundle according to the NeuroSAFE technique is performed to maximize nerve sparing during radical prostatectomy (RP) for prostate cancer (PCa). The aim of this review was to analyze oncological and functional outcomes of NeuroSAFE.

METHODS

A systematic search of the Medline, Embase, and Web of Science databases until July 2024 was performed. Studies were eligible if these included men undergoing RP with NeuroSAFE for PCa, and reported on oncological and/or functional outcomes. A cumulative analysis with random-effect models for oncological outcomes was conducted using Review Manager software, together with a narrative analysis of the procedure and functional outcomes.

KEY FINDINGS AND LIMITATIONS

We analyzed 14 studies with nine distinct patient populations; 7505 out of 15 446 patients underwent NeuroSAFE. The number of nerve-sparing procedures was higher for patients with NeuroSAFE than for controls in all studies. Cumulative analyses showed a statistically significantly lower risk of positive surgical margins (PSMs) in favor of NeuroSAFE (odds ratio [OR] 0.68, 95% confidence interval [CI] 0.51-0.91, I2 = 79%) and no difference in 2-yr biochemical recurrence (BCR; OR 0.79, 95% CI 0.53-1.18, I2 = 63%). All studies with control groups showed higher potency rates in the NeuroSAFE group; none reported significant difference in continence rates. Adverse events were scarce. Limitations of the studies include a lack of randomization resulting in a selection bias; the overall risk of bias judgment ranged from low to serious.

CONCLUSIONS AND CLINICAL IMPLICATIONS

We present the first systematic review on NeuroSAFE during RP. The level of evidence is weak. The increased rate of nerve-sparing surgery, reduced PSMs, similar BCR, and low adverse event rates imply that NeuroSAFE is an oncologically safe technique. NeuroSAFE seems to improve functional outcomes, especially potency, but results of randomized trials are awaited.

PATIENT SUMMARY

We know that for patients with prostate cancer who undergo an operation to remove the prostate, sparing the nerve bundles next to each side of the prostate improves continence and erectile function. In this literature review, we evaluated a technique (NeuroSAFE) that aids surgeons in deciding whether they can spare these nerve bundles safely while still operating radically, for example, remove all cancer. We found that the technique is oncologically safe. Furthermore, the impact on potency appears promising but needs further study.

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.

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.

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.

Intraoperative pathology consultation during urological surgery: Impact on final margin status and pitfalls of frozen section diagnosis

Despite recent improvements in diagnostic and surgical techniques in urological oncology, positive resection margin remains a significant concern for surgeons. Meanwhile, intraoperative pathology consultation with frozen section assessment (FSA), particularly for histological diagnosis of the lesions incidentally found or enlarged or sentinel lymph nodes, generally provides critical information which enables immediate decision making for optimal patient care. The intraoperative evaluation of surgical margins is also often requested, although there are some differences in its application between institutions and surgeons. Importantly, it remains to be determined whether intraoperative FSA indeed contributes to reducing the risk of final positive margins and thereby improving long-term patient outcomes. This review summarizes available data indicating the potential impact of FSA at the surgical margins during urological surgeries, including radical or partial cystectomy, partial nephrectomy, radical prostatectomy, penectomy, and orchiectomy. The accuracy and pitfalls of the intraoperative consultation/FSA diagnosis are also discussed.

NeuroSAFE frozen section during robot-assisted radical prostatectomy: peri-operative and histopathological outcomes from the NeuroSAFE PROOF feasibility randomized controlled trial

OBJECTIVES

To report on the methods, peri-operative outcomes and histopathological concordance between frozen and final section from the NeuroSAFE PROOF feasibility study (NCT03317990).

PATIENTS AND METHODS

Between May 2018 and March 2019, 49 patients at two UK centres underwent robot-assisted radical prostatectomy (RARP). Twenty-five patient were randomized to NeuroSAFE RARP (intervention arm) and 24 to standard RARP (control arm). Frozen section was compared to final paraffin section margin assessment in the 25 patients in the NeuroSAFE arm. Operation timings and complications were collected prospectively in both arms.

RESULTS

Fifty neurovascular bundles (NVBs) from 25 patients in the NeuroSAFE arm were analysed. When analysed by each pathological section (n = 250, average five per side), we noted a sensitivity of 100%, a specificity of 99.2%, and an area under the curve (AUC) of 0.994 (95% confidence interval [CI] 0.985 to 1; P ≤0.001). On an NVB basis (n = 50), sensitivity was 100%, specificity was 92.7%, and the AUC was 0.963 (95% CI 0.914 to 1; P ≤0.001). NeuroSAFE RARP lasted a mean of 3 h 16 min (knife to skin to off table, 95% CI 3 h 2 min-3 h 30 min) compared to 2 h 4 min (95% CI 2 h 2 min-2 h 25 min; P ≤0.001) for standard RARP. There was no morbidity associated with the additional length of operating time on in the NeuroSAFE arm.

CONCLUSION

This feasibility study demonstrates the safety, reproducibility and excellent histopathological concordance of the NeuroSAFE technique in the NeuroSAFE PROOF trial. Although the technique increases the duration of RARP, this does not cause short-term harm. Confirmation of feasibility has led to the opening of the fully powered NeuroSAFE PROOF randomized controlled trial, which is currently under way at four sites in the UK.

Positive surgical margin during radical prostatectomy: overview of sampling methods for frozen sections and techniques for the secondary resection of the neurovascular bundles

OBJECTIVE

The aim of the paper is to provide an overview of intraoperative sampling methods for frozen section (FS) analysis and of surgical techniques for a secondary neurovascular bundle (NVB) resection, as the method of surgical margin (SM) sampling and the management of a positive SM (PSM) at the nerve-sparing (NS) area are under evaluated issues. FS analysis during radical prostatectomy (RP) can help to tailor the plane of dissection based on cancer extension and thus extend the indications for NS surgery.

EVIDENCE ACQUISITION

We performed a PubMed/Medical Literature Analysis and Retrieval System Online (MEDLINE), Web of Science, Cochrane Library, and Elton B. Stephens Co. (EBSCO)host search to include articles published in the last decade, evaluating FS analysis in the NS area and surgical attempts to convert a PSM to a negative status.

EVIDENCE SYNTHESIS

Overall, 19 papers met our inclusion criteria. The ways to collect samples for FS analysis included: systematic (analysing the whole posterolateral aspect of the prostate specimen, i.e., neurovascular structure-adjacent frozen-section examination [NeuroSAFE]); magnetic resonance imaging (MRI)-guided (biopsies from MRI-suspicious areas, retrieved by the surgeon in a cognitive way); and random biopsies from the soft periprostatic tissues. Techniques to address a PSM in the NS area included: full resection of the spared NVB, from its caudal to cranial aspect, often including the rectolateral part of the Denonvilliers' fascia; partial resection of the NVB, in cases where sampling attempts to localise a PSM; incremental approach, meaning a partial or full resection that extends until no prostate tissue is found in the soft periprostatic environment.

CONCLUSIONS

There is no homogeneity in prostate sampling for FS analysis, although most recent evidence is moving toward a systematic sampling of the entire NS area. The management of a PSM is variable and can be affected by the sampling strategy (difficult localisation of the persisting tumour at the NVB). The difficult identification of the exact soft tissue location contiguous to a PSM could be considered as the critical point of FS analysis and of spared-NVB management.

"Real-time" Assessment of Surgical Margins During Radical Prostatectomy: State-of-the-Art

Histopathologic examination of the pathologic specimens using hematoxylin & eosin stains represents the backbone of the modern pathology. It is time-consuming; thus, "real-time" assessment of prostatic and periprostatic tissue has gained special interest in the diagnosis and management of prostate cancer. The current study focuses on the review of the different available techniques for "real-time" evaluation of surgical margins during radical prostatectomy (RP). We performed a comprehensive search of the Medline database to identify all the articles discussing "real-time" or intraoperative assessment of surgical margins during RP. Several filters were applied to the search to include only English articles performed on human subjects and published between January 2000 and March 2019. The search revealed several options for pathologic assessment of surgical margins including intraoperative frozen sections, confocal laser endomicroscopy, optical spectroscopy, photodynamic diagnosis, optical coherence tomography, multiphoton microscopy, structured illumination microscopy, 3D augmented reality, and ex vivo fluorescence confocal microscope. Frozen section represents the gold standard technique for real-time pathologic examinations of surgical margins during RP; however, several other options showed promising results in the initial clinical trials, and considering the rapid development in the field of molecular and cellular imaging, some of these options may serve as an alternative to frozen section.

The impact on oncological outcomes after radical prostatectomy for prostate cancer of converting soft tissue margins at the apex and bladder neck from tumour-positive to -negative

OBJECTIVES

To assess the impact of conversion from histologically positive to negative soft tissue margins at the apex and bladder neck on biochemical recurrence-free survival (BCRFS) and distant metastasis-free survival (DMFS) after radical prostatectomy (RP) for prostate cancer.

MATERIALS AND METHODS

The records of 2 013 patients who underwent RP and intra-operative frozen section (IFS) analysis between July 2007 and June 2016 were reviewed. IFS analysis of the urethra and bladder neck was performed, and if malignant or atypical cells remained, further resection with the aim of achieving histological negativity was carried out. Patients were divided into three groups according to the findings: those with a negative surgical margin (NSM), a positive surgical margin converted to negative (NCSM) and a persistent positive surgical margin (PSM).

RESULTS

Among the 2 013 patients, rates of NSMs, NCSMs and PSMs were 75.1%, 4.9%, and 20.0%, respectively. The 5-year BCRFS rates of patients with NSMs, NCSMs and PSMs were 89.6%, 85.1% and 57.1%, respectively (P < 0.001). In both pathological (p)T2 and pT3 cancers, the 5-year BCRFS rate for patients with NCSMs was similar to that for patients with NSMs, and higher than for patients with PSMs. The 7-year DMFS rates of patients with NSMs, NCSMs and PSMs were 97.8%, 99.1% and 89.4%, respectively (P < 0.001). Among patients with pT3 cancers, the 7-year DMFS rate was significantly higher in the NCSM group than in the PSM group (98.0% vs 86.7%; P = 0.023), but not among those with pT2 cancers (100% vs 96.9%; P = 0.616). The 5-year BCRFS rate for the NCSM group was not significantly different from that of the NSM group among the patients with low- (96.3% vs 95.8%) and intermediate-risk disease (91.1% vs 82.8%), but was lower than that of the NSM group among patients in the high-risk group (73.2% vs 54.7%).

CONCLUSIONS

Conversion of the soft tissue margin at the prostate apex and bladder neck from histologically positive to negative improved the BCRFS and DMFS after RP for prostate cancer; however, the benefit of conversion was not apparent in patients in the high-risk group.

Ex vivo MRI evaluation of prostate cancer: Localization and margin status prediction of prostate cancer in fresh radical prostatectomy specimens

PURPOSE

To investigate the ability of high field ex vivo magnetic resonance imaging (MRI) to localize prostate cancer (PCa) and to predict the margin status in fresh radical prostatectomy (RP) specimens using histology as the reference standard.

MATERIALS AND METHODS

This Institutional Review Board (IRB)-approved study had written informed consent. Patients with biopsy-proved PCa and a diagnostic multiparametric 3T MRI examination of the prostate prior to undergoing RP were prospectively included. A custom-made container provided reference between the 7T ex vivo MRI obtained from fresh RP specimens and histological slicing. On ex vivo MRI, PCa was localized and the presence of positive surgical margins was determined in a double-reading session. These findings were compared with histological findings obtained from completely cut, whole-mount embedded, prostate specimens.

RESULTS

In 12 RP specimens, histopathology revealed 36 PCa lesions, of which 17 (47%) and 20 (56%) were correlated with the ex vivo MRI in the first and second reading session, respectively. Nine of 12 (75%) index lesions were localized in the first session, in the second 10 of 12 (83%). Seven and 8 lesions of 11 lesions with Gleason score >6 and >0.5 cc were localized in the first and second session, respectively. In the first session none of the four histologically positive surgical margins (sensitivity 0%) and 9 of 13 negative margins (specificity 69%) were detected. In second session the sensitivity and specificity were 25% and 88%, respectively.

CONCLUSION

Ex vivo MRI enabled accurate localization of PCa in fresh RP specimens, and the technique provided information on the margin status with high specificity.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:439-448.