‘Mohs surgery of the prostate’: the utility of in situ frozen section analysis during robotic prostatectomy

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.

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.

Practice Patterns of Korean Urologists Regarding Positive Surgical Margins after Radical Prostatectomy: a Survey and Narrative Review

BACKGROUND

There is no clear consensus on the optimal treatment with curative intent for patients with positive surgical margins (PSMs) following radical prostatectomy (RP). The aim of this study was to investigate the perceptions and treatment patterns of Korean urologists regarding the resection margin after RP.

METHODS

A preliminary questionnaire was prepared by analyzing various studies on resection margins after RP. Eight experienced urologists finalized the 10-item questionnaire. In July 2019, the final questionnaire was delivered via e-mail to 105 urologists in Korea who specialize in urinary cancers.

RESULTS

We received replies from 91 of the 105 urologists (86.7%) in our sample population. Among them, 41 respondents (45.1%) had performed more than 300 RPs and 22 (24.2%) had completed 500 or more RPs. In the question about whether they usually performed an additional biopsy beyond the main specimen, to get information about surgical margin invasion during surgery, the main opinion was that if no residual cancer was suspected, it was not performed (74.7%). For PSMs, the Gleason score of the positive site (49.5%) was judged to be a more important prognostic factor than the margin location (18.7%), multifocality (14.3%), or margin length (17.6%). In cases with PSMs after surgery, the prevailing opinion on follow-up was to measure and monitor prostate-specific antigen (PSA) levels rather than to begin immediate treatment (68.1%). Many respondents said that they considered postoperative radiologic examinations when PSA was elevated (72.2%), rather than regularly (24.4%). When patients had PSMs without extracapsular extension (pT2R1) or a negative surgical margin with extracapsular extension (pT3aR0), the response 'does not make a difference in treatment policy' prevailed at 65.9%. Even in patients at high risk of PSMs on preoperative radiologic screening, 84.6% of the respondents said that they did not perform neoadjuvant androgen deprivation therapy. Most respondents (75.8%) indicated that they avoided nerve-sparing RP in cases with a high risk of PSMs, but 25.7% said that they had tried nerve-sparing surgery. Additional analyses showed that urologists who had performed 300 or more prostatectomies tended to attempt more nerve-sparing procedures in patients with a high risk of PSMs than less experienced surgeons (36.6% vs. 14.0%; P = 0.012).

CONCLUSION

The most common response was to monitor PSA levels without recommending any additional treatment when PSMs were found after RP. Through this questionnaire, we found that the perceptions and treatment patterns of Korean urologists differed considerably according to RP resection margin status. Refined research and standard practice guidelines are needed.

[Organoids for the advancement of intraoperative diagnostic procedures]

In the context of cancer surgery, there is always a trade-off between oncological safety and preservation of function. This is especially true in pelvic surgery due to the close relationship to the pelvic floor muscles, blood supply and nerves. Currently, risk models, preoperative imaging, the surgeon's assessment, and the intraoperative frozen section serve as the basis for decision-making. New imaging techniques and standardization in frozen section have significantly improved this in recent years. However, limitations remain due to time delays as well as more difficult correct anatomical assignment in the follow-up. Alternative intraoperative techniques may overcome this limitation in the future. Patient-derived organoids have emerged as an important new research vehicle in recent years. They are based on tumor stem cells that, under special culture conditions, form three-dimensional replicas of the original tissue. This makes them ideally suited for testing individual system therapies but also as a validation technique for new intraoperative diagnostic procedures. The Research Training Group 2543/I, which is funded by the German Research Foundation, is researching the potential of new diagnostic methods in an interdisciplinary team regarding validation in addition to intraoperative frozen sections.

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.

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.

Intraoperative Frozen Section for Margin Evaluation During Radical Prostatectomy: A Systematic Review

CONTEXT

Surgical margin status and preservation of the neurovascular bundles (NVB) are important prognostic indicators for oncological and functional outcomes of patients undergoing radical prostatectomy (RP). Intraoperative frozen section (IFS) has been used to evaluate margin status during surgery with the intention of reducing positive surgical margins (PSMs) and guiding safe preservation of the NVBs during RP, but its value is controversial.

OBJECTIVE

To evaluate current literature comparing outcomes of men undergoing RP with IFS versus RP without IFS.

EVIDENCE ACQUISITION

Medline, Embase, and Cochrane Library searches for all relevant publications (PROSPERO ID CRD42019125940), including comparative studies reporting on men undergoing RP with and without IFS, were performed. Outcomes of interest were surgical margin status, long-term oncological outcomes, NVB status, and erectile function (EF) recovery. Data were narratively synthesised in light of methodological and clinical heterogeneity of included studies.

EVIDENCE SYNTHESIS

After screening 834 publications, 10 nonrandomised retrospective comparative studies (including 16 897 patients) were retrieved. The technique of IFS differed considerably between studies. Eight studies reported a reduction in PSM rates (-1.4% to -14.5%) with IFS, though two studies report higher PSM rates (+0.4% and +10%) with IFS. Three studies reported on long-term oncological outcomes, and no difference was seen with IFS. Three studies reported on the performance of IFS systematically at the posterolateral margin of the prostate (neurovascular structure-adjacent frozen-section examination [NeuroSAFE] technique). In all these three studies, either NVB preservation or EF recovery was improved. All studies were deemed to be at either a serious or a moderate risk of bias.

CONCLUSIONS

No randomised controlled trials were identified, and significant heterogeneity existed with regard to many features of the studies included. Within the limitations of this review, the evidence suggests that IFS during RP can facilitate a modest reduction in PSM rates. There is evidence that IFS performed systematically at the posterolateral margin of the prostate can facilitate more NVB preservation. However, in the main, the lack of prospective, randomised, standardised research with long-term oncological and functional outcomes precludes strong conclusions and highlights the need for such studies.

PATIENT SUMMARY

The data of this review suggest that frozen section sampling of the prostate (ie, whilst the patient is still asleep) during prostate cancer surgery can reduce the likelihood of cancer being detected at the edge of the removed prostate. It also finds that a type of frozen section analysis (neurovascular structure-adjacent frozen-section examination [NeuroSAFE] technique) can help allow the nerves around the prostate to be left intact safely during surgery. However, the studies in this review are very different from one another and generally at a high risk of errors. Therefore, comparisons and conclusions must be made carefully.

"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.

Biomarker, Molecular, and Technologic Advances in Urologic Pathology, Oncology, and Imaging

Urologic pathology is evolving rapidly. Emerging trends include the expanded diagnostic utility of biomarkers and molecular testing, as well as adapting to the plethora of technical advances occurring in genitourinary oncology, surgical practice, and imaging. We illustrate those trends by highlighting our approach to the diagnostic workup of a few selected disease entities that pathologists may encounter, including newly recognized subtypes of renal cell carcinoma, pheochromocytoma, and prostate cancer, some of which harbor a distinctive chromosomal translocation, gene loss, or mutation. We illustrate applications of immunohistochemistry for differential diagnosis of needle core renal biopsies, intraductal carcinoma of the prostate, and amyloidosis and cite encouraging results from early studies using targeted gene expression panels to predict recurrence after prostate cancer surgery. At our institution, pathologists are working closely with urologic surgeons and interventional radiologists to explore the use of intraoperative frozen sections for margins and nerve sparing during robotic prostatectomy, to pioneer minimally invasive videoscopic inguinal lymphadenectomy, and to refine image-guided needle core biopsies and cryotherapy of prostate cancer as well as blue-light/fluorescence cystoscopy. This collaborative, multidisciplinary approach enhances clinical management and research, and optimizes the care of patients with urologic disorders.