Validation of Confocal Laser Endomicroscopy Features of Bladder Cancer: The Next Step Towards Real-time Histologic Grading

Prospective Analysis of Confocal Laser Endomicroscopy for Assessment of the Resection Bed for Bladder Tumor

Background and objective

Urothelial bladder cancer (UCB) care requires frequent follow-up cystoscopy and surgery. Confocal laser endomicroscopy (CLE), a probe-based optical technique for real-time microscopic evaluation, has shown promising accuracy for grading of UCB. We investigated the diagnostic accuracy of CLE-based assessment of the surgical radicality of the bladder resection bed (RB).

Methods

We prospectively included 40 participants scheduled for transurethral resection of bladder tumors (TURBT) in two academic hospitals. Exclusion criteria were flat lesions, fluorescein allergy, and pregnancy. We performed CLE of the RB during TURBT. Histopathology of an RB biopsy was the reference test. Results at first cystoscopy 3 mo after TURBT are reported. A panel of two blinded observers evaluated the CLE images. The diagnostic accuracy of CLE for detection of detrusor muscle (DM) and residual tumor (rT) was calculated using 2 × 2 tables.

Key findings and limitations

Histopathology for 22 CLE-matched RB biopsies revealed rT in four cases (18%) and DM in 13 (59%). The quality of CLE imaging was low in four (18%), moderate in 16 (73%), and good in two (9%) cases. CLE was able to correctly predict rT in two of the four cases (50%) identified on histopathology. The sensitivity, specificity, positive predictive value, and negative predictive value were 0.5 (95% confidence interval [CI] 0.07-0.93), 0.83 (95% CI 0.59-0.96), 0.4 (95% CI 0.05-0.85), and 0.88 (95% CI 0.64-0.99) for CLE prediction of rT, and 0.69 (95% CI 0.39-0.91), 0.33 (95% CI 0.07-0.7), 0.6 (95% CI 0.32-0.84), and 0.43 (95% CI 0.1-0.82) for prediction of DM, respectively. Five patients (23%) had rT at 3-mo follow-up; CLE had predicted rT in three, and histopathology had revealed rT in two cases at TURBT.

Conclusions and clinical implications

CLE does not appear to be a reliable tool for detecting rT or DM in the RB after TURBT.

Patient summary

We investigated a special imaging technique called confocal laser endomicroscopy (CLE) for checking the bladder after surgery for bladder cancer in a group of 40 patients. CLE results were compared to traditional biopsy results and the patients were checked after 3 months. CLE was not very reliable in detecting any remaining cancer (only 50% accurate) or important muscle tissue in the surgical area, and the quality of the images varied. While CLE shows some promise, it is not currently a dependable method for evaluating the bladder after bladder cancer surgery.

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.

French AFU Cancer Committee Guidelines - Update 2024-2026: Non-muscle invasive bladder cancer (NMIBC)

OBJECTIVE

To update the CCAFU recommendations for the management of non-muscle invasive bladder cancer (NMIBC).

METHODS

A systematic review (Medline) of the literature from 20222024 was performed, taking into account the elements of diagnosis, treatment options and monitoring of NMIBC and evaluating references with their level of evidence.

RESULTS

The diagnosis of NMIBC (Ta, T1, or CIS) is made after complete and deep tumour resection. The use of bladder photodynamic diagnosis and the indication for a second TURBT (4 to 6weeks later) help to improve the initial diagnosis. The risk of recurrence and/or tumour progression is assessed via the EORTC score. By stratifying patients into low-, intermediate- and high-risk groups, adjuvant treatment can be proposed, including endovesical instillations of chemotherapy (immediate postoperative regimen), BCG (induction and maintenance regimen), or even the indication of cystectomy for unresponsive patients.

CONCLUSION

Updating the CCAFU's recommendations should help improve patient management, as well as the diagnosis and treatment of NMIBC.

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.

French AFU Cancer Committee Guidelines - Update 2022-2024: Non-muscle-invasive bladder cancer (NMIBC)

OBJECTIVE

To update the ccAFU recommendations for the management of bladder tumours that do not infiltrate the bladder muscle (NBMIC).

METHODS

A systematic review (Medline) of the literature from 2020 to 2022 was performed, taking account of the diagnosis, treatment options and surveillance of NMIBC, while evaluating the references with their levels of evidence.

RESULTS

The diagnosis of NMIBC (Ta, T1, CIS) is made after complete full-thickness tumour resection. The use of bladder fluorescence and the indication of a second look (4-6 weeks) help to improve the initial diagnosis. The EORTC score is used to assess the risk of recurrence and/or tumour progression. Through the stratification of patients in low, intermediate and high-risk categories, adjuvant treatment can be proposed: intravesical chemotherapy (immediate postoperative, initiation regimen) or BCG (initiation and maintenance regimen) instillations, or even the indication of cystectomy for BCG-resistant patients.

CONCLUSION

Updating the ccAFU recommendations should contribute to improving patient management, as well as the diagnosis and treatment of NMIBC.

CD47-targeted optical molecular imaging and near-infrared photoimmunotherapy in the detection and treatment of bladder cancer

Transurethral resection of bladder tumor (TURBT) followed by intravesical therapy remains the most effective strategy for the management of non-muscle-invasive bladder cancer worldwide. TURBT has two purposes: to remove all visible tumors and to obtain tumor specimens for histopathological analysis. However, the detection of flat and small malignant lesions under white-light cystoscopy is extremely challenging, and residual lesions are still the main reason for the high recurrence rate of bladder cancer. We hypothesized that visual enhancement of malignant lesions using targeted optical molecular imaging could potentially highlight residual tumors in the bladder during surgery, and near-infrared photoimmunotherapy (NIR-PIT) could kill exfoliated cancer cells and residual tumors. A mouse model of complete or partial bladder tumor resection was established under the guidance of optical molecular imaging mediated by indocyanine green and anti-CD47-Alexa Fluor 790, respectively. Once the tumor recurred, mouse model received repeated CD47-targeted NIR-PIT. After complete resection, there was no tumor recurrence. Furthermore, the growth rate of recurrent tumor decreased significantly after repeated NIR-PIT. Therefore, CD47-targeted optical molecular imaging can potentially assist urologists to detect and remove all tumors, and repeated NIR-PIT shows the potential to reduce tumor recurrence rates and inhibit the growth of recurrent tumor.

Image-guided in-Vivo Needle-Based Confocal Laser Endomicroscopy in the Prostate: Safety and Feasibility Study in 2 Patients

Purpose: To assess the safety and technical feasibility of in-vivo needle-based forward-looking confocal laser endomicroscopy in prostate tissue. Methods: For this feasibility study, 2 patients with a suspicion of prostate cancer underwent transperineal needle-based confocal laser endomicroscopy during ultrasound-guided transperineal template mapping biopsies. After intravenous administration of fluorescein, needle-based confocal laser endomicroscopy imaging was performed with a forward-looking probe (outer diameter 0.9 mm) in 2 trajectories during a manual push-forward and pullback motion. A biopsy was taken in a coregistered parallel adjacent trajectory to the confocal laser endomicroscopy trajectory for histopathologic comparison. Peri- and postprocedural adverse events, confocal laser endomicroscopy device malfunction and procedural failures were recorded. Needle-based confocal laser endomicroscopy image quality assessment, image interpretation, and histology were performed by an experienced confocal laser endomicroscopy rater and uro-pathologist, blinded to any additional information. Results: In both patients, no peri- and post-procedural adverse events were reported following needle-based confocal laser endomicroscopy. No confocal laser endomicroscopy device malfunction nor procedural failures were reported. Within 1.5 min after intravenous administration of fluorescein, needle-based confocal laser endomicroscopy image quality was sufficient for interpretation for at least 14 min, yielding more than 5000 confocal laser endomicroscopy frames per patient. The pullback confocal laser endomicroscopy recordings and most of the push-forward recordings almost only visualized erythrocytes, being classified as non-representative. During the push-forward recordings, prostate tissue was occasionally visualized in single frames, insufficient for histopathologic comparison. Prostate carcinoma was identified by biopsy in one patient (Gleason score 4 + 3 = 7, >50%), while the biopsy from the other patient showed no malignancy. Conclusion: Needle-based confocal laser endomicroscopy imaging of in-vivo prostate tissue with a forward-looking confocal laser endomicroscopy probe is safe without device malfunctions or procedural failures. Needle-based confocal laser endomicroscopy is technically feasible, but the acquired confocal laser endomicroscopy datasets are non-representative. The confocal laser endomicroscopy images’ non-representative nature is possibly caused by bleeding artifacts, movement artifacts and a lack of contact time with the tissue of interest. A different confocal laser endomicroscopy probe or procedure might yield representative images of prostatic tissue.

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.

Phase II multi-center trial of optical coherence tomography as an adjunct to white light cystoscopy for intravesical real time imaging and staging of bladder cancer

BACKGROUND

Optical coherence tomography (OCT) is a novel imaging modality that provides microstructural information of different tissue layers using near-infrared light. This prospective, multicenter phase II trial aimed to assess the accuracy of OCT-assisted cystoscopy for bladder tumor staging.

METHODS

Patients with primary or recurrent bladder tumors (Ta,T1) identified by outpatient cystoscopy were included. The primary objective was to assess the accuracy and positive predictive value of for determining tumor stage ≥T1 correlated by histopathology. 72 suspicious lesions from 63 patients were eligible to analyze in the study. All suspected lesions were evaluated with conventional cystoscopy, interpreted in real-time using OCT, and then resected. All results were compared to pathology. A total of 363 OCT images of tumor and normal mucosa in 25 patients were obtained to evaluate diagnostic efficacy of the computer-aided texture analysis algorithm.

RESULTS

Sensitivity and specificity for predicting invasive tumors (≥ T1, n = 17) were 58.8% and 92.7% for cystoscopy, 64.7% and 100% for OCT-assisted cystoscopy, respectively. Accuracy of cystoscopy and OCT-assisted cystoscopy for predicting invasive tumor was 84.7% and 91.7% (P = 0.063), respectively. Cystoscopy and OCT-assisted cystoscopy correctly predicted T stage in 52/72 and 59/72 cases, respectively (P = 0.016). Cystoscopy missed 2 more invasive tumors than OCT-assisted cystoscopy. Cystoscopy (14.3%, 1/7) and OCT-assisted cystoscopy (28.6%, 2/7) showed relatively low sensitivity in detecting muscle invasion. Computer aided texture analysis demonstrated 75.1% sensitivity, 64.0% specificity, and 74.4% accuracy for differentiating tumor and normal urothelium.

CONCLUSION

OCT-assisted cystoscopy is a real time noninvasive and simple procedure that enhanced the accuracy of staging bladder tumors and prediction of any tumor invasion. Though the study did not meet the prespecified primary endpoint, OCT imaging is a promising adjunct to cystoscopy that may supplement intraoperative decision-making during transurethral resection of bladder tumors and additional prospective studies are warranted.

En Bloc Tumor Resection, Optical Molecular Imaging, and the Potential Synergy of the Combination of the Two Techniques in Bladder Cancer

Although transurethral resection of bladder tumor is the golden standard for the treatment of non-muscle invasive bladder cancer, this surgical procedure still has some serious drawbacks. For example, piecemeal resection of tumor tissue results in exfoliated tumor cells dissemination and implantation, and fragmented tumor specimens make it difficult for pathologists to accurately assess the pathological stage and histologic grade. En bloc tumor resection follows the basic principle of oncological surgery and provides an intact tumor specimen containing detrusor muscle for pathologists to make accurate histopathological assessment. However, there is no robust clinical evidence that en bloc tumor resection is superior to conventional resection in terms of oncological outcomes. Considering the high recurrence rate, small or occult tumor lesions may be overlooked and incomplete tumor resection may occur during white light cystoscopy-assisted transurethral resection. Molecular fluorescent tracers have the ability to bind tumor cells with high sensitivity and specificity. Optical molecular imaging mediated by it can detect small or occult malignant lesions while minimizing the occurrence of false-positive results. Meanwhile, optical molecular imaging can provide dynamic and real-time image guidance in the surgical procedure, which helps urologists to accurately determine the boundary and depth of tumor invasion, so as to perform complete and high-quality transurethral tumor resection. Integrating the advantages of these two technologies, optical molecular imaging-assisted en bloc tumor resection shows the potential to improve the positive detection rate of small or occult tumor lesions and the quality of transurethral resection, resulting in high recurrence-free and progression-free survival rates.

Initial Results of First In Vivo Imaging of Bladder Lesions Using a High-Resolution Confocal Microendoscope

Purpose: Conventional cystoscopy plays an important role in detection of bladder cancer; however, it is difficult to differentiate benign and neoplastic lesions based on cystoscopic appearance alone. Advanced microscopic modalities, such as confocal laser endomicroscopy and optical coherence tomography, have been shown to provide critical histopathologic information to help identify neoplastic bladder lesions in real time, but their availability and clinical adoption are limited due to a high cost. In this study, we present the first use of a novel and low-cost ($ <5000) confocal high-resolution microendoscope (confocal HRME) for in vivo imaging of bladder lesions. Materials and Methods: In a cohort of 15 patients undergoing white light cystoscopy as part of their standard of care, high-resolution images of proflavine-stained bladder lesions were acquired in vivo using the confocal HRME. Based on these images, we evaluated the ability of the confocal HRME to visualize uroepithelium with subcellular resolution and high contrast. Furthermore, we analyzed the cellular architecture and staining patterns of benign and neoplastic bladder lesions in confocal HRME images and compared results to that of standard cystoscopy and histopathology. Results: In vivo imaging in the pilot study demonstrates that the confocal HRME resolved subcellular structures of bladder uroepithelium with high contrast. In a wide range of clinical conditions from normal bladder wall to benign and neoplastic lesions, confocal HRME images revealed important diagnostic features that correlated to histopathology. Conclusions: The confocal HRME provides an affordable, portable, and easy-to-use tool to allow real-time and high-contrast subcellular characterization of bladder lesions, well suited for bladder cancer detection in community and resource-constrained settings. The ClinicalTrials.gov Identifier: NCT02340650.

Carcinoma in situ of the bladder: why is it underdetected?

PURPOSE OF REVIEW

The standard diagnosis of carcinoma in situ (CIS) of the bladder, based on white light cystoscopy and urine cytology, is limited because CIS can vary from normal-appearing mucosa to a lesion indistinguishable from an inflammatory process. Intravesical instillation of Bacillus Calmette-Guerin (BCG) remains first-line therapy; however, a significant proportion of cases persist or recur after BCG treatment. This review summarizes recent improvements in the detection and treatment of CIS.

RECENT FINDINGS

The new optical technologies improve CIS detection, with a potential positive impact on oncological outcomes. The usefulness of MRI-photodynamic diagnosis fusion transurethral resection in CIS detection is unclear and further studies are needed. BCG instillation remains the first-line therapy in CIS patients and seems to improve recurrence and progression rates, especially with the use of maintenance. Intravesical device-assisted therapies could be effective in both BCG-naïve and BCG-unresponsive CIS patients, but further studies are ongoing to clarify their clinical benefit. A phase II clinical trial with pembrolizumab has shown the potential effectiveness of immune checkpoint inhibitors in BCG-unresponsive CIS patients and further trials are ongoing.

SUMMARY

New optical techniques increase the CIS detection rate. BCG instillation remains the first-line treatment. Immune checkpoint inhibitors could be a future alternative in BCG-naïve and BCG-unresponsive CIS patients.

En bloc resection of bladder tumors: indications, techniques, and future directions

PURPOSE OF REVIEW

En bloc resection of bladder tumor (ERBT) is an innovative new surgical technique, the use of which is becoming increasingly widespread. In this review, we analyze the recent literature and explore new developments, which may impact the future role of en bloc bladder surgery.

RECENT FINDINGS

ERBT increases the frequency with which detrusor muscle is present in the specimen (to 95%) and offers a significant improvement in the quality of the resection specimen, thereby helping with T1 substaging. Furthermore, the laser treatment reduces the rate of obturator nerve-related bladder perforation.

SUMMARY

ERBT represents a considerable advancement in the surgical management of nonmuscle-invasive bladder cancer. It delivers excellent oncological results and is a well tolerated procedure.

VIDEO

In the accompanying video, we shortly report the different modalities and energy sources used for bladder cancer resection. The three strategies are currently employed at the Fundació Puigvert (Barcelona). VIDEO ABSTRACT:.

Diagnostic value of probe-based confocal laser endomicroscopy versus conventional endoscopic biopsies of non-muscle invasive bladder tumors: a pilot study

PURPOSE

The standard procedure for diagnostics and follow-up for non-muscle invasive bladder cancer (NMIBC) is cystoscopy in the outpatient clinic. Suspicious lesions are biopsied for histopathological assessment. This pilot study aimed to evaluate the ability of Confocal Laser Endomicroscopy (CLE) to rule out High Grade Urothelial Carcinoma (HGUC) to select patients for in-office fulguration.

MATERIALS AND METHODS

We performed a prospective non-randomized, single surgeon study. Intraoperative CLE was performed independently by the surgeon and a blinded on-site uropathologist. Following the procedure, a CLE evaluation was performed by another blinded urologist. Lesions were classified as normal/inflammatory, Low Grade Urothelial Carcinoma (LGUC) or HGUC. With the histological evaluations as the gold standard we calculated sensitivity, specificity, PPV and NPV for HGUC and the accuracy for each CLE assessor. The primary outcome was the NPV for HGUC for the surgeon.

RESULTS

Twelve patients with a total of 34 lesions were included. Six lesions were flat and 28 were exophytic. On histopathology, 25 lesions were classified as normal/inflammatory or LGUC, while nine were classified as HGUC. For the surgeon, the uropathologist and the second urologist, the sensitivity was 44%, 78% and 22%, respectively. Specificities for the three observers were 84%, 68% and 96%. This corresponded to PPVs for HGUC of 50%, 47% and 67% and NPV for HGUC of 81%, 89% and 77%.

CONCLUSIONS

In our hands the NPV of CLE is not high enough for it to be considered an alternative to histopathological assessment of bladder lesions.

Endoscopic Molecular Imaging plus Photoimmunotherapy: A New Strategy for Monitoring and Treatment of Bladder Cancer

Due to the high recurrence and progression rate of non-muscle invasive bladder cancer after transurethral resection of bladder tumor, some new optical imaging technologies have arisen as auxiliary imaging modes for white light cystoscopy to improve the detection rate of small or occult tumor lesions, such as photodynamic diagnosis, narrow-band imaging, and molecular imaging. White light cystoscopy is inadequate and imperfect for bladder cancer detection, and thus residual tumors or coexisting flat malignant lesions, especially carcinoma in situ, would be ignored during conventional resection. The bladder, a hollow organ with high compliance, provides an ideal closed operation darkroom for endoscopic molecular imaging free from interference of external light sources. Also, intravesical instillation of a molecular fluorescent tracer is simple and convenient before surgery through the urethra. Molecular fluorescent tracer has high sensitivity and specificity to tumor cells, and its mediated molecular imaging allows small or occult tumor lesion detection while minimizing false-positive results. Meanwhile, endoscopic molecular imaging provides a real-time and dynamic image during surgery, which helps urologists to perform high-quality and complete tumor resection through accurate judgment of tumor boundaries and depth of invasion. Photoimmunotherapy is a novel molecular targeted therapeutic pattern of photodynamic therapy that kills malignant cells selectively and minimizes the cytotoxicity to normal tissues. The combination of endoscopic molecular imaging and photoimmunotherapy used in initial treatment may avoid the need of repeat transurethral resection in strictly selected patients and improve oncological outcomes such as recurrence-free survival and overall survival after operation.

Optimal Management of Upper Tract Urothelial Carcinoma: Current Perspectives

INTRODUCTION

Upper tract urothelial carcinoma (UTUC) is a relatively uncommon urologic malignancy for which there has not been significant improvement in survival over the past few decades, highlighting the need for optimal multi-modality management.

METHODS

A non-systematic review of the latest literature was performed to include relevant articles up to June 2019. It summarizes the epidemiologic risk factors associated with UTUC, including smoking, carcinogenic aromatic amines, arsenic, aristolochic acid, and Lynch syndrome. Molecular pathways underlying UTUC and potential druggable targets are outlined.

RESULTS

Surgical management for UTUC includes kidney-sparing surgery (KSS) for low-risk disease and radical nephroureterectomy (RNU) for high-risk disease. Endoscopic management of UTUC may include ureteroscopic or percutaneous resection. Topical instillation therapy post-KSS aims to reduce recurrence, progression and to treat carcinoma-in-situ; this may be achieved retrogradely (via ureteric catheterization), antegradely (via percutaneous nephrostomy) or via reflux through double-J stent. RNU, which may be performed via open, laparoscopic or robot-assisted approaches, is the gold standard treatment for high-risk UTUC. The distal cuff may be dealt with extravesical, transvesical or endoscopic techniques. Peri-operative chemotherapy and immunotherapy are increasingly utilized; level 1 evidence exists for adjuvant chemotherapy, but neoadjuvant chemotherapy is favored as kidney function is better prior to RNU. Immunotherapy is primarily reserved for metastatic UTUC but is currently being investigated in the perioperative setting.

CONCLUSION

The optimal management of UTUC includes a firm understanding of the epidemiological factors and molecular pathways. Surgical management includes KSS for low-risk disease and RNU for high-risk disease. Peri-operative immunotherapy and chemotherapy may be considered as evidence mounts.

Toward Automated In Vivo Bladder Tumor Stratification Using Confocal Laser Endomicroscopy

Purpose: Urothelial carcinoma of the bladder (UCB) is the most common urinary cancer. White-light cystoscopy (WLC) forms the corner stone for the diagnosis of UCB. However, histopathological assessment is required for adjuvant treatment selection. Probe-based confocal laser endomicroscopy (pCLE) enables visualization of the microarchitecture of bladder lesions during WLC, which allows for real-time tissue differentiation and grading of UCB. To improve the diagnostic process of UCB, computer-aided classification of pCLE videos of in vivo bladder lesions were evaluated in this study. Materials and Methods: We implemented preprocessing methods to optimize contrast and to reduce striping artifacts in each individual pCLE frame. Subsequently, a semiautomatic frame selection was performed. The selected frames were used to train a feature extractor based on pretrained ImageNet networks. A recurrent neural network, in specific long short-term memory (LSTM), was used to predict the grade of bladder lesions. Differentiation of lesions was performed at two levels, namely (i) healthy and benign vs malignant tissue and (ii) low-grade vs high-grade papillary UCB. A total of 53 patients with 72 lesions were included in this study, resulting in ∼140,000 pCLE frames. Results: The semiautomated frame selection reduced the number of frames to ∼66,500 informative frames. The accuracy for differentiation of (i) healthy and benign vs malignant urothelium was 79% and (ii) high-grade and low-grade papillary UCB was 82%. Conclusions: A feature extractor in combination with LSTM results in proper stratification of pCLE videos of in vivo bladder lesions.

Optical biopsy of bladder cancer using confocal laser endomicroscopy

OBJECTIVE

Confocal laser endomicroscopy (CLE) is an emerging endoscopic technique that can provide in vivo histopathologic information. It may improve the diagnostic criteria for benign and neoplastic lesions of the bladder. In this study, we reported our experience with utilizing CLE imaging when treating bladder neoplasms, and investigated its diagnostic value with respect to histologic diagnosis.

MATERIALS AND METHODS

Twenty-one patients scheduled for diagnostic cystoscopy or transurethral resection of the bladder tumor were enrolled prospectively. CLE was performed after intravesical fluorescein administration and confocal video sequences were reviewed and analyzed retrospectively. Histopathology served as reference standard for comparison.

RESULTS

Confocal laser endomicroscopy-based classification combined with white light cystoscopy (WLC) images was consistent with histopathology in 17 cases (81.0%). Consensus with histopathological results was found in six cases (85.7%) for low-grade urothelial carcinoma and eight cases (80.0%) for high-grade urothelial carcinoma.

CONCLUSION

Confocal laser endomicroscopy was proved to be a useful technique that could complement white light cystoscopy by providing real-time histopathological information of bladder lesions.

Confocal laser endomicroscopy for upper tract urothelial carcinoma: validation of the proposed criteria and proposal of a scoring system for real-time tumor grading

Purpose

Confocal laser endomicroscopy (CLE) is a fluorescence-based fiber-optic imaging technique with the potential for intraoperative grading of upper tract urothelial carcinoma (UTUC). This study aims to (1) investigate the prevalence of the previously proposed CLE criteria for bladder cancer in papillary UTUC, (2) estimate the diagnostic value of CLE for UTUC grading and (3) propose a scoring system for a more quantifiable approach of CLE-based grading of UTUC.

Materials and methods

Ureteroscopic CLE was performed in patients with UTUC. Following CLE imaging, co-localized biopsies were taken for histopathologic comparison. Postoperatively, two blinded raters assessed the CLE images.

Results

Fifty-three papillary UTUCs (34 low grade and 19 high grade) were imaged with CLE in 36 patients. All the previously described CLE criteria were identifiable in varying proportions. After excluding 10 non-diagnostic recordings (5 low grade and 5 high grade) due to insufficient image quality, the histopathologic grade was correctly identified with CLE in 26 low-grade UTUCs (90%) and in 12 high-grade UTUCs (86%). The most prevalent CLE criteria with the highest diagnostic potential were cellular organization, morphology and cohesiveness of cells. A scoring system was proposed with these criteria, which yielded similar diagnostic accuracies.

Conclusions

Based on the previously proposed criteria, CLE enables accurate grading of papillary UTUC at a non-diagnostic rate of 19%. The most prevalent CLE criteria with the highest diagnostic potential for grading of papillary UTUC are cellular organization, morphology and cohesiveness of cells. The proposed scoring system may simplify the assessment of CLE images for UTUC grading but external validation is required.

Novel real-time optical imaging modalities for the detection of neoplastic lesions in urology: a systematic review

BACKGROUND

Current optical diagnostic techniques for malignancies are limited in their diagnostic accuracy and lack the ability to further characterise disease, leading to the rapidly increasing development of novel imaging methods within urology. This systematic review critically appraises the literature for novel imagining modalities, in the detection and staging of urological cancer and assesses their effectiveness via their utility and accuracy.

METHODS

A systematic literature search utilising MEDLINE, EMBASE and Cochrane Library Database was conducted from 1970 to September 2018 by two independent reviewers. Studies were included if they assessed real-time imaging modalities not already approved in guidelines, in vivo and in humans. Outcome measures included diagnostic accuracy and utility parameters, including feasibility and cost.

RESULTS

Of 5475 articles identified from screening, a final 46 were included. Imaging modalities for bladder cancer included optical coherence tomography (OCT), confocal laser endomicroscopy, autofluorescence and spectroscopic techniques. OCT was the most widely investigated, with 12 studies demonstrating improvements in overall diagnostic accuracy (sensitivity 74.5-100% and specificity 60-98.5%). Upper urinary tract malignancy diagnosis was assessed using photodynamic diagnosis (PDD), narrow band imaging, optical coherence tomography and confocal laser endomicroscopy. Only PDD demonstrated consistent improvements in overall diagnostic accuracy in five trials (sensitivity 94-96% and specificity 96.6-100%). Limited evidence for optical coherence tomography in percutaneous renal biopsy was identified, with anecdotal evidence for any modality in penile cancer.

CONCLUSIONS

Evidence supporting the efficacy for identified novel imaging modalities remains limited at present. However, OCT for bladder cancer and PDD in upper tract malignancy demonstrate the best potential for improvement in overall diagnostic accuracy. OCT may additionally aid intraoperative decision making via real-time staging of disease. Both modalities require ongoing investigation through larger, well-conducted clinical trials to assess their diagnostic accuracy, use as an intraoperative staging aid and how to best utilise them within clinical practice.