Clinical benefits of frozen section assessment during urological surgery: Does it contribute to improving surgical margin status and patient outcomes as previously thought?

Virtual Staining of Nonfixed Tissue Histology

Surgical pathology workflow involves multiple labor-intensive steps, such as tissue removal, fixation, embedding, sectioning, staining, and microscopic examination. This process is time-consuming and costly and requires skilled technicians. In certain clinical scenarios, such as intraoperative consultations, there is a need for faster histologic evaluation to provide real-time surgical guidance. Currently, frozen section techniques involving hematoxylin and eosin (H&E) staining are used for intraoperative pathology consultations. However, these techniques have limitations, including a turnaround time of 20 to 30 minutes, staining artifacts, and potential tissue loss, negatively impacting accurate diagnosis. To address these challenges, researchers are exploring alternative optical imaging modalities for rapid microscopic tissue imaging. These modalities differ in optical characteristics, tissue preparation requirements, imaging equipment, and output image quality and format. Some of these imaging methods have been combined with computational algorithms to generate H&E-like images, which could greatly facilitate their adoption by pathologists. Here, we provide a comprehensive, organ-specific review of the latest advancements in emerging imaging modalities applied to nonfixed human tissue. We focused on studies that generated H&E-like images evaluated by pathologists. By presenting up-to-date research progress and clinical utility, this review serves as a valuable resource for scholars and clinicians, covering some of the major technical developments in this rapidly evolving field. It also offers insights into the potential benefits and drawbacks of alternative imaging modalities and their implications for improving patient care.

Distinguishing Renal Cell Carcinoma From Normal Kidney Tissue Using Mass Spectrometry Imaging Combined With Machine Learning

PURPOSE

Accurately distinguishing renal cell carcinoma (RCC) from normal kidney tissue is critical for identifying positive surgical margins (PSMs) during partial and radical nephrectomy, which remains the primary intervention for localized RCC. Techniques that detect PSM with higher accuracy and faster turnaround time than intraoperative frozen section (IFS) analysis can help decrease reoperation rates, relieve patient anxiety and costs, and potentially improve patient outcomes.

MATERIALS AND METHODS

Here, we extended our combined desorption electrospray ionization mass spectrometry imaging (DESI-MSI) and machine learning methodology to identify metabolite and lipid species from tissue surfaces that can distinguish normal tissues from clear cell RCC (ccRCC), papillary RCC (pRCC), and chromophobe RCC (chRCC) tissues.

RESULTS

From 24 normal and 40 renal cancer (23 ccRCC, 13 pRCC, and 4 chRCC) tissues, we developed a multinomial lasso classifier that selects 281 total analytes from over 27,000 detected molecular species that distinguishes all histological subtypes of RCC from normal kidney tissues with 84.5% accuracy. On the basis of independent test data reflecting distinct patient populations, the classifier achieves 85.4% and 91.2% accuracy on a Stanford test set (20 normal and 28 RCC) and a Baylor-UT Austin test set (16 normal and 41 RCC), respectively. The majority of the model's selected features show consistent trends across data sets affirming its stable performance, where the suppression of arachidonic acid metabolism is identified as a shared molecular feature of ccRCC and pRCC.

CONCLUSION

Together, these results indicate that signatures derived from DESI-MSI combined with machine learning may be used to rapidly determine surgical margin status with accuracies that meet or exceed those reported for IFS.

The impact of routine frozen section analysis during nephroureterectomy or segmental ureterectomy for urothelial carcinoma on final surgical margin status and long-term oncologic outcome

OBJECTIVE

The utility of intraoperative frozen section analysis (FSA) at the surgical margins (SMs) in patients with upper urinary tract cancer has not been established. We herein assessed the clinical significance of routine FSA of ureteral SMs during nephroureterectomy (NU) or segmental ureterectomy (SU).

MATERIALS AND METHODS

A retrospective review of our Surgical Pathology database identified consecutive patients undergoing NU (n=246) or SU (n=42) for urothelial carcinoma from 2004 to 2018. FSA (n=54) was correlated with the diagnosis of frozen section controls, the status of final SMs, and the prognosis of patients.

RESULTS

During NU, FSA was performed in 19 (7.7%) patients and was significantly more often requested in cases with ureteral tumor (13.1%) than in those with renal pelvis/calyx tumor (3.5%). Final SMs at the distal ureter/bladder cuff were positive only in non-FSA cases in the entire NU cohort (8.4%; P=0.375) or those with tumor at the lower ureter (57.6%; P=0.046), but not in any of FSA patients (0%). During SU, FSA was performed in 35 (83.3%) cases, including 19 at either proximal or distal SM and 16 at both SMs (SU-FSA2). Final positive SMs were significantly more often detected in non-FSA patients (42.9%) than in all FSA (8.6%; P=0.048) or SU-FSA2 (0%; P=0.020) patients. Overall, FSAs were reported as positive or high-grade carcinoma (n=7), atypical or dysplasia (n=13), and negative (n=34), and all these diagnoses were confirmed accurate on the frozen section controls, except one with a revision from atypical to carcinoma in situ. Meanwhile, 16 (80.0%) of 20 cases with initial positive/atypical FSA achieved negative conversion by excision of additional tissue. Kaplan-Meier analysis revealed that SU-FSA did not significantly reduce the risk of tumor recurrence in the bladder, disease progression, or cancer-specific mortality. Nonetheless, NU-FSA was strongly associated with reduced progression-free (P=0.023) and cancer-specific (P=0.007) survival rates, compared with non-FSA, which may imply a selection bias (e.g., FSA for clinically more aggressive tumors).

CONCLUSIONS

Performing FSA during NU for lower ureteral tumor, as well as during SU, significantly reduced the risk of positive SMs. However, routine FSA for upper urinary tract cancer failed to considerably improve long-term oncologic outcome.

Venous thrombosis, multiple carcinomatous foci and differences in metastatic pathways of penile carcinoma

The aim of the present study was to explore the life-threatening complications and metastatic pathways of penile squamous cell carcinoma (SCC), as numerous patients with penile cancer are relatively young, are of good general health and have no visceral metastasis, yet have poor survival rates. A total of 94 patients with SCC of the penis who were surgically treated were included in the current study. The coagulation parameters, including prothrombin time (PT), fibrinogen and D-dimer, were analyzed. The patients' age ranged from 25 to 95 years (mean ± standard deviation, 53.3±1.4 years). A total of 77 patients (81.9%) underwent partial penectomy and 17 (18.1%) underwent radical penectomy. The PT was significantly different between patients whose tumour invaded the corpora cavenosum and those whose tumour had not invaded, and between patients with and without pelvic lymph node metastasis. A negative correlation was obtained between PT and pelvic lymph node metastasis. In addition, six typical SCC cases and one metastatic penile carcinoma case manifested with multiple carcinomatous foci, embolisms and evidence of a metastatic pathway occurring simultaneously with tumour progression were presented. The present study indicated that venous thrombosis is one of the life-threatening complications of advanced penile cancer. Furthermore, multiple carcinomatous foci were detected in histological images. Of note, direct clinical evidence for different metastatic pathways of primary and secondary penile carcinoma was provided.

How accurate is frozen section pathology compared to permanent pathology in detecting involved margins and lymph nodes in breast cancer?

Background

Frozen section (FS) pathology has multiple limitations, and different institutions report variable experiences with the use of FS for diagnosis of tumor involvement. We aimed to compare the FS accuracy with that of permanent pathology (gold standard) regarding marginal involvement and lymph node status using data from the largest breast cancer registry in Iran.

Methods

In this retrospective study, women who had both FS and permanent pathology reports were included. The two pathology reports were cross compared with regard to the involvement of tumor margins and sentinel lymph nodes.

Results

Overall, 2786 patients entered the study. Mean age of patients was 48.96±11.44 years. A total of 1742 margins were analyzed. Accordingly, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of FS pathology for detection of involvement of involved margins were 78.49%, 97.63%, 65.1%, and 98.7%, respectively. The accuracy and area under the curve (AUC) for FS pathology were 96.61% and 0.73 (95% CI: 0.64–0.831), respectively.

A total of 1702 sentinel lymph node biopsies were assessed. Sensitivity, specificity, PPV, and NPV, of FS pathology for detection of lymph node involvement, were 87.1%, 98%, 95.5%, and 93.3%, respectively. Accuracy and AUC of FS for diagnosis of involved lymph nodes were 94.1% and 0.926 (95% CI: 0.909–0.942), respectively.

Conclusion

Frozen pathology is a suitable method for identifying involved sentinel lymph nodes in patients with breast cancer, but this method has a less than optimum efficacy for detecting and confirming marginal involvement.

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.

Does intraoperative frozen section really predict significant positive surgical margins after robot-assisted laparoscopic prostatectomy? A retrospective study

We investigated the relationship between positive surgical margin (PSM)-related factors and biochemical recurrence (BCR) and the ability of intraoperative frozen sections to predict significant PSM in patients with prostate cancer. The study included 271 patients who underwent robot-assisted laparoscopic prostatectomy with bilateral nerve sparing and maximal urethral preservation. Intraoperative frozen sections of the periurethra, dorsal vein, and bladder neck were analyzed. The ability of PSM-related factors to predict BCR and significant PSM was assessed by logistic regression. Of 271 patients, 108 (39.9%) had PSM and 163 (60.1%) had negative margins. Pathologic Gleason score ≥8 (18.9% vs 7.5%, P = 0.015) and T stage ≥T3a (51.9% vs 24.6%, P < 0.001) were significantly more frequent in the PSM group. Multivariate analysis showed that Gleason pattern ≥4 (vs <4; hazard ratio: 4.386; P = 0.0004) was the only significant predictor of BCR in the PSM cohort. Periurethral frozen sections had a sensitivity of 83.3% and a specificity of 84.2% in detecting PSM with Gleason pattern ≥4. Multivariate analysis showed that membranous urethra length (odds ratio [OR]: 0.79, P = 0.0376) and extracapsular extension of the apex (OR: 4.58, P = 0.0226) on magnetic resonance imaging (MRI) and positive periurethral tissue (OR: 17.85, P < 0.0001) were associated with PSM of the apex. PSM with Gleason pattern ≥4 is significantly predictive of BCR. Intraoperative frozen sections of periurethral tissue can independently predict PSM, whereas sections of the bladder neck and dorsal vein could not. Pathologic examination of these samples may help predict significant PSM in patients undergoing robot-assisted laparoscopic prostatectomy with preservation of functional outcomes.

The impact of routine frozen section analysis during partial cystectomy for bladder cancer on surgical margin status and long-term oncologic outcome

OBJECTIVES

The utility of frozen section analysis (FSA) during partial cystectomy has not been established. We assessed the impact of intraoperative FSA in partial cystectomy cases on surgical margin (SM) status and patient outcome.

SUBJECTS AND METHODS

A retrospective review identified 76 consecutive patients who underwent partial cystectomy for bladder carcinoma with (n = 66; 87%) or without (n = 10; 13%) FSA for SMs at our institution from 2004 to 2018. FSA was correlated with the diagnosis of the frozen section control, the status of final SM, and the prognosis.

RESULTS

Final SM was positive in 9 (12%) cystectomies, including 6 (9%) FSA vs. 3 (30%) non-FSA cases (P = 0.091). There were no significant differences in tumor size, histology, or tumor grade/stage between the 2 cohorts. FSAs were reported as positive (n = 7; 11%), atypical (n = 10; 15%), and negative (n = 49; 74%). All of the positive and negative FSA diagnoses were confirmed accurate on the frozen section controls, whereas atypical diagnoses were revised to benign (n = 4), atypical (n = 4), and carcinoma (n = 2) on the controls. Ten (77%) of 13 initial FSA-positive (6 of 7)/atypical (4 of 6; excluding benign diagnoses on the controls) cases achieved negative conversion by excision of additional tissue. Thus, final SM was positive in 1 (14%) FSA-positive case, 3 (30%) FSA-atypical cases (including one at the SM where FSA was not sampled), and 2 (4%) FSA-negative cases (at the SM where FSA was not sampled). Kaplan-Meier analysis and log-rank test revealed an association of performing FSA with the risk of disease progression (P = 0.021), but not intravesical recurrence (P = 0.434) or cancer-specific mortality (P = 0.560). Initial positive/atypical FSA, as an independent prognosticator, was associated with reduced progression-free (P = 0.002) and cancer-specific (P = 0.004) survival rates, compared with initial negative FSA. Positive SM was also associated with a larger tumor size (P < 0.05) and a higher risk of intravesical recurrence (P = 0.070) or disease progression (P = 0.096).

CONCLUSIONS

Performing FSA during partial cystectomy may contribute to preventing positive SM and disease progression. Additionally, as seen in most of initial FSA-positive/atypical cases that achieved negative conversion, select patients may benefit from the routine FSA. Meanwhile, positive or atypical FSA was associated with significantly poorer prognosis.

Investigation of confocal microscopy for differentiation of renal cell carcinoma versus benign tissue. Can an optical biopsy be performed?

Objective

Novel optical imaging modalities are under development with the goal of obtaining an “optical biopsy” to efficiently provide pathologic details. One such modality is confocal microscopy which allows in situ visualization of cells within a layer of tissue and imaging of cellular-level structures. The goal of this study is to validate the ability of confocal microscopy to quickly and accurately differentiate between normal renal tissue and cancer.

Methods

Specimens were obtained from patients who underwent robotic partial nephrectomy for renal mass. Samples of suspected normal and tumor tissue were extracted from the excised portion of the kidney and stained with acridine orange. The stained samples were imaged on a Nikon E600 C1 Confocal Microscope. The samples were then submitted for hematoxylin and eosin processing and read by an expert pathologist to provide a gold-standard diagnosis that can later be compared to the confocal images.

Results

This study included 11 patients, 17 tissue samples, and 118 confocal images. Of the 17 tissue samples, 10 had a gold-standard diagnosis of cancer and seven were benign. Of 118 confocal images, 66 had a gold-standard diagnosis of cancer and 52 were benign. Six confocal images were used as a training set to train eight observers. The observers were asked to rate the test images on a six point scale and the results were analyzed using a web based receiver operating characteristic curve calculator. The average accuracy, sensitivity, specificity, and area under the empirical receiver operating characteristic curve for this study were 91%, 98%, 81%, and 0.94 respectively.

Conclusion

This preliminary study suggest that confocal microscopy can be used to distinguish cancer from normal tissue with high sensitivity and specificity. The observers in this study were trained quickly and on only six images. We expect even higher performance as observers become more familiar with the confocal images.

The value of transperineal apical prostate biopsy in predicting urethral/apical margin status after radical prostatectomy

PURPOSE

To investigate potential preoperative predictors of urethral or apical positive surgical margin (PSM) and the value of apical prostate biopsy in predicting urethral/apical margin status after radical prostatectomy (RP).

METHODS

A total of 531 patients who underwent RP during 2010 to 2017 at West China Hospital were enrolled in this retrospective study. Preoperative and postoperative factors including age, BMI, PSA, clinical T stage and biopsy Gleason score were analyzed. Univariate analysis and logistic regression were used to find out the potential predictive factors for PSM. Two logistic regression models were built to evaluate the role of apical prostate biopsy in predicting urethral/apical margin status.

RESULTS

The overall PSM rate was about 30.1% (160/531) and 97 of them were reported urethral/apical PSM. The incidence of urethral or apical PSM in patients with positive cores in the apical prostate was higher than those without (23.0% vs 9.9%, P < .001). We further found that the multivariable model with positive apical prostate biopsy could significantly increase the predictive value of urethral or apical PSM status (AUC: 0.744 vs 0.783, P = .016). Our analysis also showed that neo-adjuvant hormone therapy was an independent protective factor for urethral or apical PSM in patients with positive apical prostate biopsy, but not all patients.

CONCLUSION

This study revealed the necessity of apical prostate biopsy to predict the risk of apical or urethral PSM. In clinical practice, neo-adjuvant hormone therapy should be given when patients with positive apical prostate biopsy to reduce the presence of PSM, especially patients with high/very high risk prostate cancer.

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.

Fluorescent Light-Guided Cystoscopy with 5-ALA Aids in Accurate Surgical Margin Detection for TURBO: A Case Report

Recent studies have revealed that transurethral resection in one piece (TURBO) has several benefits over standard transurethral resection of bladder tumor (TUR-Bt), including a higher rate of containing the bladder muscle tissue and single-block resection. Five-aminolevulinic acid (5-ALA) was approved for the detection of bladder tumor treated with TUR-Bt. A 71-year-old male patient who received right nephroureterectomy developed bladder tumor recurrence on routine cystoscopy follow-up. We planned TURBO using fluorescent light-guided cystoscopy with 5-ALA. We herein report a case of bladder tumor successfully treated with TURBO using fluorescent light-guided cystoscopy with 5-ALA to detect the tumor surgical margin.