Probe-Based Confocal Laser Endomicroscopy During Transurethral Resection of Bladder Tumors Improves the Diagnostic Accuracy and Therapeutic Efficacy

Grading urothelial carcinoma with probe-based confocal laser endomicroscopy during flexible cystoscopy

PURPOSE

Urothelial bladder cancer (UCB) care requires frequent follow-up cystoscopy and surgery. Confocal laser endomicroscopy (CLE) is a probe-based optical technique that can provide real-time microscopic evaluation with the potential for outpatient grading of UCB. This study aims to investigate the diagnostic accuracy and interobserver variability for the grading of UCB with CLE during flexible cystoscopy (fCLE).

METHODS

Participants scheduled for transurethral resection of papillary bladder tumors were prospectively included for intra-operative fCLE. Exclusion criteria were flat lesions, fluorescein allergy or pregnancy. Two independent observers evaluated fCLE, classifying tumors as low- or high-grade urothelial carcinoma (LGUC/HGUC) or benign. Interobserver agreement was calculated with Cohens kappa (κ) and diagnostic accuracy with 2 × 2 tables. Histopathology was the reference test.

RESULTS

Histopathology of 34 lesions revealed 14 HGUC, 14 LGUC and 6 benign tumors. Diagnostic yield for fCLE was 80-85% with a κ of 0.75. Respectively, sensitivity, specificity, NPV and PPV were: for benign tumors 0-20%, 96-100%, unmeasureable-50% and 87%, for LGUC 57-64%, 41-58%, 44-53% and 54-69% and for HGUC 38-57%, 56-68%, 38-57% and 56-68%, with an interobserver agreement of κ 0.61.

CONCLUSION

fCLE is currently insufficient to grade UCB.

Advanced optical imaging techniques for bladder cancer detection and diagnosis: a systematic review

OBJECTIVES

To systematically assess the current available literature concerning advanced optical imaging methods for the detection and diagnosis of bladder cancer (BCa), focusing particularly on the sensitivity and specificity of these techniques.

METHODS

First a scoping search was performed to identify all available optical techniques for BCa detection and diagnosis. The optical imaging techniques used for detecting BCa are: the Storz professional image enhancement system (IMAGE1 S), narrow-band imaging (NBI), photoacoustic imaging (PAI), autofluorescence imaging (AFI), photodynamic diagnosis (PDD), and scanning fibre endoscopy (SFE). The staging and grading techniques for BCa are: optical coherence tomography (OCT), confocal laser endomicroscopy (CLE), Raman spectroscopy, endocytoscopy, and non-linear optical microscopy (NLO). Then a systematic literature search was conducted using MEDLINE, EMBASE and Web of Science from inception to 21 November 2023. Articles were screened and selected by two independent reviewers. Inclusion criteria were: reporting on both the sensitivity and specificity of a particular technique and comparison to histopathology, and in the case of a detection technique comparison to white light cystoscopy (WLC).

RESULTS

Out of 6707 articles, 189 underwent full-text review, resulting in 52 inclusions. No articles met criteria for IMAGE1 S, PAI, SFE, Raman spectroscopy, and endocytoscopy. All detection techniques showed higher sensitivity than WLC, with NBI leading (87.8-100%). Overall, detection technique specificity was comparable to WLC, with PDD being most specific (23.3-100%). CLE and OCT varied in sensitivity and specificity, with OCT showing higher specificity for BCa diagnosis, notably for carcinoma in situ (97-99%) compared to CLE (62.5-81.3%). NLO demonstrated high sensitivity and specificity (90-97% and 77-100%, respectively) based on limited data from two small ex vivo studies.

CONCLUSIONS

Optical techniques with the most potential are PDD for detecting and OCT for staging and grading BCa. Further research is crucial to validate their integration into routine practice and explore the value of other imaging techniques.

Cystoscopy Accuracy in Detecting Bladder Tumors: A Prospective Video-Confirmed Study

BACKGROUND

Bladder cancer ranks as the 10th most common cancer globally. The diagnosis of bladder tumors typically involves cystoscopy.

OBJECTIVE

This study aimed to evaluate the sensitivity and specificity of cystoscopy in detecting bladder tumors within a surveillance program following a bladder cancer diagnosis.

DESIGN, SETTING, AND PARTICIPANTS

This study utilized recordings of cystoscopies conducted at the Department of Urology, Zealand University Hospital, between July 2021 and November 2022. Clinical observations were cross-referenced with pathological results or follow-up cystoscopies. Clinically negative cystoscopies were further scrutinized for potential overlooked tumors.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Sensitivity and specificity of cystoscopy were assessed through ROC curve analysis.

RESULTS AND LIMITATIONS

A total of 565 cystoscopies were recorded, with 135 indicating clinical positivity. Among 181 cystoscopies with clinically negative results that underwent a follow-up cystoscopy, 17 patients (9.4%) were subsequently diagnosed with bladder cancer, with the lesions identified in the initial cystoscopy. The sensitivity and specificity of cystoscopy in these cases were 81% and 73%, respectively.

CONCLUSION

This trial underscores the underdiagnosis and undertreatment of bladder tumors within the current surveillance program. Additionally, aggressive malignant lesions may be overlooked, heightening the risk of disease progression. Therefore, it is recommended that cystoscopies be complemented by other diagnostic methods to ensure accurate diagnosis and proper patient treatment.

PATIENT SUMMARY

This study involved 316 patients who underwent video-recorded cystoscopies and subsequent follow-up. Of these patients, 181 initially exhibited no clinical signs of bladder cancer. However, upon reviewing the recorded cystoscopy, bladder cancer was identified in 17 patients (9.4%).

Fluorescence Confocal Microscopy in Urological Malignancies: Current Applications and Future Perspectives

Fluorescence confocal microscopy (FCM) represents a novel diagnostic technique able to provide real-time histological images from non-fixed specimens. As a consequence of its recent developments, FCM is gaining growing popularity in urological practice. Nevertheless, evidence is still sparse, and, at the moment, its applications are heterogeneous. We performed a narrative review of the current literature on this topic. Papers were selected from the Pubmed, Embase, and Medline archives. We focused on FCM applications in prostate cancer (PCa), urothelial carcinoma (UC), and renal cell carcinoma (RCC). Articles investigating both office and intraoperative settings were included. The review of the literature showed that FCM displays promising accuracy as compared to conventional histopathology. These results represent significant steps along the path of FCM's formal validation as an innovative ready-to-use diagnostic support in urological practice. Instant access to a reliable histological evaluation may indeed significantly influence physicians' decision-making process. In this regard, FCM addresses this still unmet clinical need and introduces intriguing perspectives into future diagnostic pathways. Further studies are required to thoroughly assess the whole potential of this technique.

Bladder augmentation from an insider's perspective: a review of the literature on microcirculatory studies

Augmentation cystoplasty is an exemplary multiorgan intervention in urology which is particularly associated with microvascular damage. Our aim was to review the available intravital imaging techniques and data obtained from clinical and experimental microcirculatory studies involving the most important donor organs applied in bladder augmentation. Although numerous direct or indirect methods are available to assess the condition of microvessels the implementation of microcirculatory diagnostic methods in humans is still challenging and the assessment of organ microcirculation in the operating theatre has limitations. Nevertheless, preclinical studies generally report good internal validity and although prospective human protocols with reduced variability are needed, a possible positive impact of microcirculatory diagnostics on the clinical outcomes of urologic surgery can be anticipated.

Deep Neural Network for Differentiation of Brain Tumor Tissue Displayed by Confocal Laser Endomicroscopy

Background

Reliable on site classification of resected tumor specimens remains a challenge. Implementation of high-resolution confocal laser endoscopic techniques (CLEs) during fluorescence-guided brain tumor surgery is a new tool for intraoperative tumor tissue visualization. To overcome observer dependent errors, we aimed to predict tumor type by applying a deep learning model to image data obtained by CLE.

Methods

Human brain tumor specimens from 25 patients with brain metastasis, glioblastoma, and meningioma were evaluated within this study. In addition to routine histopathological analysis, tissue samples were stained with fluorescein ex vivo and analyzed with CLE. We trained two convolutional neural networks and built a predictive level for the outputs.

Results

Multiple CLE images were obtained from each specimen with a total number of 13,972 fluorescein based images. Test accuracy of 90.9% was achieved after applying a two-class prediction for glioblastomas and brain metastases with an area under the curve (AUC) value of 0.92. For three class predictions, our model achieved a ratio of correct predicted label of 85.8% in the test set, which was confirmed with five-fold cross validation, without definition of confidence. Applying a confidence rate of 0.999 increased the prediction accuracy to 98.6% when images with substantial artifacts were excluded before the analysis. 36.3% of total images met the output criteria.

Conclusions

We trained a residual network model that allows automated, on site analysis of resected tumor specimens based on CLE image datasets. Further in vivo studies are required to assess the clinical benefit CLE can have.

Diagnostic Performance of Confocal Laser Endomicroscopy for the Detection of Bladder Cancer: Systematic Review and Meta-Analysis

OBJECTIVE

To systematically evaluate the diagnostic efficacy of confocal laser endomicroscopy (CLE) in detection of bladder cancer.

METHODS

A systematic literature search on CLE in diagnosing bladder cancer in PubMed, Embase, and the Cochrane Library databases was performed. A bivariate meta-regression model was used for meta-analysis to evaluate the pooled diagnostic value of CLE.

RESULTS

A total of 5 eligible studies involving 302 lesions were available for this meta-analysis. In a per-lesion analysis, pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and summary receiver-operating curve (SROC) area under the curve (AUC) of CLE for malignant lesions were 0.90 (95% confidence interval [CI]: 0.85-0.94), 0.72 (95% CI: 0.59-0.82), 3.20 (95% CI: 2.14-4.79), 0.14 (95% CI: 0.09-0.21), 23.27 (95% CI: 11.71-46.25), and 0.91 (95% CI: 0.89-0.94), respectively. For low-grade urothelial carcinomas, pooled sensitivity, specificity, PLR, NLR, DOR, and AUC for CLE were 0.72 (95% CI: 0.57-0.84), 0.87 (95% CI: 0.77-0.93), 5.48 (95% CI: 3.12-9.62), 0.32 (95% CI: 0.20-0.50), 17.19 (95% CI: 8.01-36.89), and 0.85 (95% CI: 0.82-0.88), respectively. For high-grade urothelial carcinomas, pooled sensitivity, specificity, PLR, NLR, DOR, and AUC for CLE were 0.82 (95% CI: 0.62-0.92), 0.84 (95% CI: 0.73-0.91), 4.96 (95% CI: 2.58-9.54), 0.22 (95% CI: 0.09-0.52), 22.49 (95% CI: 5.33-94.85), and 0.89 (95% CI: 0.86-0.91), respectively.

CONCLUSION

CLE is a promising endoscopy technique for real-time tumor grading of bladder cancer.