Application of new technology in bladder cancer diagnosis and treatment

Bladder cancer biomarkers: current approaches and future directions

Bladder cancer is a significant health concern worldwide, necessitating effective diagnostic and monitoring strategies. Biomarkers play a crucial role in the early detection, prognosis, and treatment of this disease. This review explores the current landscape of bladder cancer biomarkers, including FDA-approved molecular biomarkers and emerging ones. FDA-approved molecular biomarkers, such as BTA stat, BTA TRAK, and NMP22, have been instrumental in diagnosing and monitoring bladder cancer. These biomarkers are derived from urinary samples and are particularly useful due to their sensitivity and specificity. As we move forward, we should continue to seek ways to optimize our processes and outcomes, these markers remain seriously challenged in the detection of early bladder cancer due to their limited sensitivity and specificity. For instance, sensitivities of BTA stat in bladder tumor detection have varied between 40-72%, while its specificities vary from 29-96%. In the same way, 70% sensitivity and 80% specificity have been recorded for BTA TRAK, while 11-85.7% sensitivity and 77-100% specificity have been documented for NMP22 BladderChek. The given variations, especially the low sensitivity in the diagnosis of bladder cancer at an early stage call for the invention of better diagnostic systems. Moreover, different sample collection and handling procedures applied in different laboratories further contribute to inconsistent results obtained. Extracellular vesicles (EVs) and exosomes, which carry a vast number of proteins, are being considered as potential biomarkers. Although these markers show promise, challenges remain due to non-standardized isolation techniques and lack of reproducibility across studies. Moreover, the discovery of new potential biomarkers is ongoing. For instance, the UBC® Rapid test and UBC ELISA kit, the XPERT BC Monitor, BC UroMark, TaqMan® Arrays, Soluble FAS (sFAS), Bladder tumor fibronectin (BTF), and IGF2 and MAGE-A3 are among the newest biomarkers under investigation. In conclusion, while bladder cancer biomarkers have shown great promise, more research is needed to standardize the testing procedures and validate these biomarkers in a clinical setting. This will pave the way for more accurate and efficient diagnosis and monitoring of bladder cancer, ultimately improving patient outcomes.

Deep learning diagnostics for bladder tumor identification and grade prediction using RGB method

We evaluate the diagnostic performance of deep learning artificial intelligence (AI) for bladder cancer, which used white-light images (WLIs) and narrow-band images, and tumor grade prediction of AI based on tumor color using the red/green/blue (RGB) method. This retrospective study analyzed 10,991 cystoscopic images of suspicious bladder tumors using a mask region-based convolutional neural network with a ResNeXt-101-32 × 8d-FPN backbone. The diagnostic performance of AI was evaluated by calculating sensitivity, specificity, and diagnostic accuracy, and its ability to detect cancers was investigated using the dice score coefficient (DSC). Using the support vector machine model, we analyzed differences in tumor colors according to tumor grade using the RGB method. The sensitivity, specificity, diagnostic accuracy and DSC of AI were 95.0%, 93.7%, 94.1% and 74.7%. In WLIs, there were differences in red and blue values according to tumor grade (p < 0.001). According to the average RGB value, the performance was ≥ 98% for the diagnosis of benign vs. low-and high-grade tumors using WLIs and > 90% for the diagnosis of chronic non-specific inflammation vs. carcinoma in situ using WLIs. The diagnostic performance of the AI-assisted diagnosis was of high quality, and the AI could distinguish the tumor grade based on tumor color.

Narrow band imaging versus white light cystoscopy alone for transurethral resection of non-muscle invasive bladder cancer

BACKGROUND

Disease recurrence and progression remain major challenges for the treatment of non-muscle invasive bladder cancer. Narrow band imaging (NBI) is an optical enhancement technique that may improve resection of non-muscle invasive bladder cancer and thereby lead to better outcomes for people undergoing the procedure.  OBJECTIVES: To assess the effects of NBI- and white light cystoscopy (WLC)-guided transurethral resection of bladder tumor (TURBT) compared to WLC-guided TURBT in the treatment of non-muscle invasive bladder cancer.

SEARCH METHODS

We performed a comprehensive literature search of 10 databases, including the Cochrane Library, the Cochrane Database of Systematic Reviews, MEDLINE, Embase, several clinical trial registries, and grey literature for published and unpublished studies, irrespective of language. The search was performed per an a priori protocol on 3 December 2021.

SELECTION CRITERIA

We included randomized controlled trials of participants with suspected or confirmed non-muscle invasive bladder cancer. Participants in the control group must have received WLC-guided TURBT alone (hereinafter simply referred to as 'WLC TURBT'). Participants in the intervention group had to have received NBI- and WLC-guided TURBT (hereinafter simply referred to as 'NBI + WLC TURBT').

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion/exclusion, performed data extraction, and assessed risk of bias. We conducted meta-analysis on time-to-event and dichotomous data using a random-effects model in RevMan, according to Cochrane methods. We rated the certainty of evidence for each outcome according to the GRADE approach. Primary outcomes were time to recurrence, time to progression, and the occurrence of a major adverse event, defined as a Clavien-Dindo III, IV, or V complication. Secondary outcomes included time to death from bladder cancer and the occurrence of a minor adverse event, defined as a Clavien-Dindo I or II complication.  MAIN RESULTS: We included eight studies with a total of 2152 participants randomized to the standard WLC TURBT or to NBI + WLC TURBT. A total of 1847 participants were included for analysis.  Based on limited confidence in the time-to-event data, we found that participants who underwent NBI + WLC TURBT had a lower risk of disease recurrence over time compared to participants who underwent WLC TURBT (hazard ratio 0.63, 95% CI 0.45 to 0.89; I2 = 53%; 6 studies, 1244 participants; low certainty of evidence). No studies examined disease progression as a time-to-event outcome or a dichotomous outcome. There was likely no difference in the risk of a major adverse event between participants who underwent NBI + WLC TURBT and those who underwent WLC TURBT (risk ratio 1.77, 95% CI 0.79 to 3.96; 4 studies, 1385 participants; low certainty of evidence). No studies examined death from bladder cancer as a time-to-event outcome or a dichotomous outcome. There was likely no difference in the risk of a minor adverse event between participants who underwent NBI + WLC TURBT and those who underwent WLC TURBT (risk ratio 0.88, 95% CI 0.49 to 1.56; I2 = 61%; 4 studies, 1385 participants; low certainty of evidence).  AUTHORS' CONCLUSIONS: Compared to WLC TURBT alone, NBI + WLC TURBT may lower the risk of disease recurrence over time while having little or no effect on the risks of major or minor adverse events.

Role of Macroscopic Image Enhancement in Diagnosis of Non-Muscle-Invasive Bladder Cancer: An Analytical Review

Early diagnosis of non-muscle-invasive bladder cancer (NMIBC) is of paramount importance to prevent morbidity and mortality due to bladder cancer. Although white light imaging (WLI) cystoscopy has long been considered the gold standard in the diagnosis of bladder cancer, it can miss lesions in a substantial percentage of patients and is very likely to miss carcinoma in situ and dysplasia. Tumor margin detection by WLI can be inaccurate. Moreover, WLI could, sometimes, be inadequate in distinguishing inflammation and malignancy. To improve the diagnostic efficacy of cystoscopy, various optical image enhancement modalities have been studied. These image enhancement modalities have been classified as macroscopic, microscopic, or molecular. Photodynamic diagnosis (PDD), narrow band imaging (NBI), and Storz image 1 S enhancement (formerly known as SPIES) are macroscopic image enhancement modalities. A relevant search was performed for literature describing macroscopic image enhancement modalities like PDD, NBI, and image 1 S enhancement. The advantages, limitations, and usefulness of each of these in the diagnosis of bladder cancer were studied. Photodynamic diagnosis requires intravesical instillation of a photosensitizing agent and a special blue light cystoscope system. PDD has been shown to be more sensitive than WLI in the detection of bladder cancer. It is superior to WLI in the detection of flat lesions. Bladder tumor resection (TURBT) by PDD results in more complete resection and reduced recurrence rates. PDD-guided TURBT may have some role in reducing the risk of progression. Narrow band imaging provides increased contrast between normal and abnormal tissues based on neovascularization, thereby augmenting WLI. NBI requires a special light source. There is no need for intravesical contrast instillation. NBI is superior to WLI in the detection of bladder cancer. The addition of NBI to WLI improves the detection of flat lesions like carcinoma in situ. NBI is not useful in predicting invasive tumors or grades of tumors. NBI-directed TURBT reduces recurrence rates and recurrence free survival. But its efficacy in retarding progression is unproven. Image 1 S-enhancement utilizes software-based image enhancement modes without the need for a special light source or intravesical contrast instillation. This system provides high-quality images and identifies additional abnormal-looking areas. Another advantage of this system is simultaneous side-by-side visualization of WLI and enhanced image, providing WLI images as the control for comparison. As with PDD, S-enhancement produces a lower rate of a missed bladder cancer diagnosis. The system significantly improves the diagnosis of NMIBC. The sensitivity and negative predictive value of image 1 S enhancement increase with the increase in cancer grade. A negative test by S-enhancement effectively rules out NMIBC. All the image enhancement modalities have proven their utility in improving detection and short-term cancer control. But none of these modalities have proven their utility in delaying progression, or in long-term cancer control. Cancer progression and long-term control are governed by the biological nature of cancer cells. Early detection by optical enhancement may not be of utility in this regard. Well-designed studies are needed to establish the efficacy of these modalities in the evaluation of patients with bladder cancer. The last word, in this regard, is yet to be written.

The use of artificial intelligence for the diagnosis of bladder cancer: a review and perspectives

PURPOSE OF REVIEW

White light cystoscopy is the current standard for primary diagnosis and surveillance of bladder cancer. However, cancer changes can be subtle and may be easily missed. With the advancement of deep learning (DL), image recognition by artificial intelligence (AI) proves a high accuracy for image-based diagnosis. AI can be a solution to enhance bladder cancer diagnosis on cystoscopy.

RECENT FINDINGS

An algorithm that classifies cystoscopic images into normal and tumour images is essential for AI cystoscopy. To develop this AI-based system requires a training dataset, an appropriate type of DL algorithm for the learning process and a specific outcome classification. A large data volume with minimal class imbalance, data accuracy and representativeness are pre-requisite for a good dataset. Algorithms developed during the past two years to detect bladder tumour achieved high performance with a pooled sensitivity of 89.7% and specificity of 96.1%. The area under the curve ranged from 0.960 to 0.980, and the accuracy ranged from 85.6 to 96.9%. There were also favourable results in the various attempts to enhance detection of flat lesions or carcinoma-in-situ.

SUMMARY

AI cystoscopy is a possible solution in clinical practice to enhance bladder cancer diagnosis, improve tumour clearance during transurethral resection of bladder tumour and detect recurrent tumours upon surveillance.

Urine cytology suspicious for urothelial carcinoma: Prospective follow-up of cases using cytology and urine biomarker-based ancillary techniques

BACKGROUND

Urine cytology results that are suspicious for urothelial carcinoma (UC) are challenging. The objective of this study was to elucidate the clinical significance of such results in patients who have a negative cystoscopy.

METHODS

In this prospective study, 83 patients who had urine cytology that was suspicious of UC and a negative cystoscopy underwent a second cystoscopy and urine evaluation by cytology, UroVysion fluorescence in situ hybridization (FISH) assay, FGFR3 (fibroblast growth factor receptor 3) and TERT (telomerase reverse transcriptase) mutations and an 8-gene expression classifier (GEC). Results from all techniques were compared with patients' clinical outcomes.

RESULTS

The presence of tumor was identified in 41% of patients; of these, 82% had tumors identified at their second evaluation (76% high-grade [HG] tumors), and 18% had tumors identified at a later follow-up (50% were HG tumors). After The Paris System for Reporting urinary Cytology (TPS) reclassification, 53 cytology results still had an indeterminate diagnosis (13 were suspicious for HGUC, and 40 had atypical urothelial cells (AUCs)]. Complete results from second evaluations using urine cytology, cytology-TPS, FISH, and GEC were available for 6 cases that were suspicious for HGUC and 34 cases that had AUCs. The sensitivity of these techniques to detect HG tumors in cases that were suspicious for HGUC was 100%, except for cytology-TPS, for which the sensitivity was 50%. The sensitivity of cytology and cytology-TPS to detect HG tumors in cases with AUCs was 33%, whereas the sensitivity of fluorescence in situ hybridization and GEC in these cases was 83% and 75%, respectively, to detect HG tumors at the second evaluation.

CONCLUSIONS

The current results indicate the relevant clinical significance of indeterminate urine cytology findings and strongly suggest the use of complementary evaluations by urine biomarker-based, ancillary techniques to elucidate their significance.

Identifying non-muscle-invasive and muscle-invasive bladder cancer based on blood serum surface-enhanced Raman spectroscopy

The assessment of the muscle invasion of bladder cancer typically plays a crucial role in therapeutic decision-making and has significant impacts on the recurrence rate and survival rate. Although histopathology is sufficiently accurate and usually served as the gold standard for bladder cancer diagnosis, it is invasive, time-consuming, and requires intensive sample preparation by a well-trained pathologist to achieve an optimal diagnosis. Therefore, a fast and noninvasive method to accurately identify non-muscle-invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC) is in demand. In this study, the SERS technique combined with the PLS-LDA method based on a small amount of blood serum samples is employed to distinguish healthy volunteers, NMIBC, and MIBC patients. According to the results, the overall diagnostic accuracy is 93.3%. The diagnostic accuracies are 97.8% and 93.2% for healthy versus bladder cancer groups and NMIBC versus MIBC groups, respectively. Therefore, the proposed method has demonstrated excellent performance on accurately identifying muscle invasion of bladder cancer, which can assist timely diagnosis and proper treatment for bladder cancer patients.

Ability of a urine gene expression classifier to reduce the number of follow-up cystoscopies in bladder cancer patients

This study aimed to improve our previous urine gene expression classifiers focusing on the detection of non-high-risk non-muscle-invasive bladder cancer (NMIBC), and develop a new classifier able to decrease the frequency of cystoscopies during bladder cancer (BC) patients' surveillance. A total of 597 urines from BC patients, controls and patients in follow-up for BC (PFBC) were included. The study has 3 phases. In the urinary biomarker discovery phase, 84 urines from BC and control patients were retrospectively included and analyzed by Ribonucleic Acid (RNA) sequencing. In the classifier development phase, a total of 132 selected genes from previous phase were evaluated by nCounter in 214 prospectively collected urines from PFBC (98 with tumor). A diagnostic classifier was generated by logistic regression. Finally, in the classifier validation phase, a multicentric and international cohort of 248 urines (134 BC and 114 nonrecurrent PFBC) was used to validate classifier performance. A total of 521 genes were found differentially expressed between non-high-risk NMIBC samples and all other groups (P < 0.05). An 8-gene diagnostic classifier with an area under curve (AUC) of 0.893 was developed. Validation of this classifier in a cohort of PFBC achieved an overall sensitivity (SN) and a negative predictive value (NPV) of 96% and 97%, respectively (AUC = 0.823). Notably, this accuracy was maintained in non-high-risk NMIBC group (SN = 94%; NPV = 98%). In conclusion, this 8-gene expression classifier has high SN and NPV in a real clinical scenario. The use of this classifier can reduce the number of follow-up cystoscopies in PFBC, although assessing its final place in clinical setting is necessary.

Recent advances in optical imaging technologies for the detection of bladder cancer

White-light cystoscopy (WLC) is the diagnostic standard for the detection of bladder cancer (BC). However, the detection of small papillary and subtle flat carcinoma in situ lesions is not always possible with WLC. Several adjunctive optical imaging technologies have been developed to improve BC detection and resection. Photodynamic diagnosis, which requires the administering of a photoactive substance, has a higher detection rate than WLC for the detection of BC. Narrow-band imaging provides better visualization of tumors by contrast enhancement between normal mucosa and well-vascularized lesions. A technology called confocal laser endomicroscopy can be used to obtain detailed images of tissue structure. Optical coherence tomography is a high-resolution imaging process that enables noninvasive, real-time, and high-quality tissue images. Several other optical imaging technologies are also being developed to assist with the detection of BC. In this review, we provide an overview of the strengths and weaknesses of these imaging technologies for the detection of BC.

Diagnostic accuracy of optical coherence tomography in bladder cancer patients: A systematic review and meta-analysis

A meta-analysis was performed to evaluate the accuracy of optical coherence tomography (OCT) for diagnostic accuracy studies in bladder cancer patients. English language studies reporting the diagnostic accuracy of OCT for bladder cancer were retrieved from the PubMed, EMBASE and Cochrane Library databases in December 2014. Histopathology was a reference standard. Sensitivities, specificities, positive likelihood ratios and negative likelihood ratios were calculated, and summary receiver operating characteristic curves were drawn to determine the diagnostic accuracy of OCT. Finally, 9 eligible studies (468 patients) were included in our meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio and negative likelihood ratio of OCT were 0.96 [95% confidence interval (CI): 0.94-0.98], 0.82 (95% CI: 0.80-0.85), 6.83 (95% CI: 3.24-14.1) and 0.05 (95% CI: 0.02-0.16), respectively. The summary diagnostic odds ratio was 138.88 (95% CI: 29.63-650.89) and the overall area under the curve was 0.9735. These results suggest that OCT has excellent diagnostic performance in patients with bladder cancer and recurrent lesions.

Clinical performance and utility of a NNMT-based urine test for bladder cancer

BACKGROUND

Bladder cancer (BC) represents the most common neoplasm of the urinary tract. Although cystoscopy and urine cytology represent the gold standard methods to monitor BC, both procedures have limitations. Therefore, the identification of reliable biomarkers for early and noninvasive detection of BC is urgently required.

METHODS

In this study, we analyzed nicotinamide N-methyltransferase (NNMT) expression in urine samples from 55 BC patients and 107 controls, using real-time polymerase chain reaction (PCR). Receiver operating characteristic (ROC) analysis was used to identify the best cutoff value to discriminate BC patients from healthy donors, and to evaluate the diagnostic accuracy of a urine-based NNMT test.

RESULTS

The results demonstrated that urinary NNMT expression was significantly (p<0.05) higher in BC patients. Moreover, a significant (p<0.05) inverse correlation was found between NNMT expression and histological grade. The ROC analysis revealed that a ΔCq of 13.3 was the best cutoff value, since it was associated with the highest combination of sensitivity and specificity. Moreover, the area under the curve (AUC) value was 0.913 (p<0.05), indicating the excellent diagnostic accuracy of a urine-based NNMT test.

CONCLUSIONS

Our data indicate that NNMT is a promising biomarker that could be used to support the early and noninvasive diagnosis of BC.

Narrow band imaging-assisted transurethral resection reduces the recurrence risk of non-muscle invasive bladder cancer: A systematic review and meta-analysis

CONTEXT

Compared with white light imaging (WLI) cystoscopy, narrow band imaging (NBI) cystoscopy could increase the visualization and detection of bladder cancer (BC) at the time of transurethral resection (TUR). NBI cystoscopy could increase the detection of BC, but it remains unclear whether narrow band imaging-assisted transurethral resection (NBI-TUR) could reduce the recurrence risk of non-muscle invasive bladder cancer (NMIBC). Several randomized clinical trials (RCTs) have recently tested the efficacy of NBI-TUR for NMIBC.

OBJECTIVE

To perform a systematic review and meta-analysis of RCTs and evaluate the efficacy of NBI-TUR for NMIBC compared with white light imaging-assisted transurethral resection (WLI-TUR). The end point was recurrence risk.

EVIDENCE ACQUISITION

A systematic review of PubMed, Medline, Ovid, Embase, Cochrane and Web of Science was performed in February 2016 and updated in July 2016.

EVIDENCE SYNTHESIS

Overall, six (n = 1084) of 278 trials were included. Three trials performed narrow band imaging-assisted electro-transurethral resection (NBI-ETUR), and two trials performed narrow band imaging-associated bipolar plasma vaporization (NBI-BPV). The last trial performed narrow band imaging-associated holmium laser resection (NBI-HLR). Statistical analysis was performed using Review Manager software (RevMan v.5.3; The Nordic Cochrane Center, Copenhagen, Denmark). The recurrence risk was compared by calculating risk ratios (RRs) with 95% confidence interval (CIs). Risk ratios with 95% CIs were calculated to compare 3-mo, 1-yr, and 2-yr survival rates. NBI-TUR was associated with improvements in the 3-mo recurrence risk (RR: 0.39; 95% CI, 0.26-0.60; p < 0.0001), 1-yr recurrence risk (RR: 0.52; 95% CI, 0.40-0.67; p < 0.00001) and 2-yr recurrence risk (RR: 0.60; 95% CI, 0.42-0.85; p = 0.004) compared with WLI-TUR.

CONCLUSIONS

Compared with WLI-TUR, NBI-TUR can reduce the recurrence risk of NMIBC. The results of this review will facilitate the appropriate application of NBI in NMIBC.

Comparison of White Light, Photodynamic Diagnosis, and Narrow-band Imaging in Detection of Carcinoma In Situ or Flat Dysplasia at Transurethral Resection of the Bladder: the DaBlaCa-8 Study

OBJECTIVE

To compare findings in NBI to findings in WL and PDD in a high-risk patient population.

MATERIALS AND METHODS

A total of 171 patients were included in the study from 4 different urology departments in Denmark and Norway. Patients were scheduled for a PDD-guided transurethral tumor resection or cystoscopy-guided biopsy in accordance with Danish guidelines, on the suspicion of primary or concomitant CIS. All patients were examined with WL cystoscopy followed by both NBI and PDD before biopsy.

RESULTS

A total of 136 patients were biopsied due to findings with suspicion of CIS in at least 1 modality (482 biopsies with a mean of 3.5 biopsies per patient). Analysis at patient level showed that NBI and PDD had a significantly higher sensitivity regarding identification of CIS and dysplasia compared with WL (NBI: 95.7%, PDD: 95.7% vs WL: 65.2%, P < .05). Specificity was not significantly different between the 3 methods (NBI: 52.0%, PDD: 48.0%, and WL: 56.8%). When analyzed per biopsy, NBI and PDD had a significantly higher sensitivity than WL (NBI: 72.7% and PDD: 78.2% vs WL: 52.7%, P < .05), whereas the positive predictive values were not significantly different (NBI: 23.7%, PDD: 22.2%, and WL: 19.0%).

CONCLUSION

NBI was found to be a valid alternative to PDD regarding diagnosis of CIS and flat dysplasia.

Gene expression test for the non-invasive diagnosis of bladder cancer: A prospective, blinded, international and multicenter validation study

OBJECTIVE

This study aimed to validate, in a prospective, blinded, international and multicenter cohort, our previously reported four non-invasive tests for bladder cancer (BC) diagnosis based on the gene expression patterns of urine.

METHODS

Consecutive voided urine samples from BC patients and controls were prospectively collected in five European centres (n=789). Finally, 525 samples were successfully analysed. Gene expression values were quantified using TaqMan Arrays and previously reported diagnostic algorithms were applied to gene expression data. Results from the most accurate gene signature for BC diagnosis were associated with clinical parameters using analysis of variance test.

RESULTS

High diagnostic accuracy for the four gene signatures was found in the independent validation set (area under curve [AUC]=0.903-0.918), with the signature composed of two genes (GS_D2) having the best performance (sensitivity: 81.48%; specificity: 91.26%; AUC: 0.918). The diagnostic accuracy of GS_D2 was not affected by the number of tumours (p=0.58) but was statistically associated with tumour size (p=0.008). Also, GS_D2 diagnostic accuracy increases with increasing BC tumour risk. We found no differences in the performance of the GS_D2 test among the populations and centres in detecting tumours (p=0.7) and controls (p=0.2).

CONCLUSIONS

Our GS_D2 test is non-invasive, non-observer dependent and non-labour-intensive, and has demonstrated diagnostic accuracy in an independent, international and multicenter study, equal or superior to the current gold standard (cystoscopy combined with cytology). Additionally, it has higher sensitivity than cytology while maintaining its specificity. Consequently, it meets the requirements for consideration as a molecular test applicable to clinical practice in the management of BC.

Multiphoton microscopy: a potential intraoperative tool for the detection of carcinoma in situ in human bladder

CONTEXT

Urothelial carcinoma in situ (CIS) is a precursor of invasive bladder cancer, which if left untreated, will likely progress to more aggressive disease. Approximately 50% of CIS lesions are missed on routine cystoscopy owing to their flat architecture. Furthermore, many benign but abnormal-appearing areas may be biopsied owing to lack of cellular resolution of cystoscopes. Multiphoton microscopy (MPM) is an optical imaging technique that generates subcellular-resolution three-dimensional images from unfixed tissue without using exogenous dyes.

OBJECTIVE

To assess the diagnostic potential of MPM in identifying and differentiating benign from malignant flat bladder lesions, especially CIS.

DESIGN

Seventy-eight specimens (benign = 46, CIS = 23, invasive = 9, as diagnosed on histopathology) were obtained from flat bladder mucosa via transurethral resection of bladder, cold cup biopsy, or cystectomy, imaged fresh with a commercial benchtop MPM, and submitted for routine histopathology. Multiphoton microscopy and hematoxylin-eosin diagnoses were compared.

RESULTS

In 77 of 78 specimens (99%), accurate MPM diagnoses (benign/malignant) were given on the basis of their architectural and cytologic features (nuclear to cytoplasmic ratio, pleomorphism, polarity/organization of urothelial layers, etc). The sensitivity and specificity were 97% and 100%, respectively, with positive (malignant) and negative (benign) predictive values of 100% and 98%, respectively. The interobserver agreement, κ, was 0.93.

CONCLUSIONS

Our study demonstrates the capability of MPM to identify and differentiate benign from malignant flat bladder lesions, especially CIS. With the advent of MPM endoscopes, we foresee their potential as a biopsy guidance tool for early detection and treatment of CIS, thus reducing the rate of biopsies with benign diagnoses and their associated complications.

A network meta-analysis of therapeutic outcomes after new image technology-assisted transurethral resection for non-muscle invasive bladder cancer: 5-aminolaevulinic acid fluorescence vs hexylaminolevulinate fluorescence vs narrow band imaging

Background

This study included a network meta-analysis of evidence from randomized controlled trials (RCTs) to assess the therapeutic outcome of transurethral resection (TUR) in patients with non-muscle-invasive bladder cancer assisted by photodynamic diagnosis (PDD) employing 5-aminolaevulinic acid (5-ALA) or hexylaminolevulinate (HAL) or by narrow band imaging (NBI).

Methods

Relevant RCTs were identified from electronic databases. The proceedings of relevant congresses were also searched. Fifteen articles based on RCTs were included in the analysis, and the comparisons were made by qualitative and quantitative syntheses using pairwise and network meta-analyses.

Results

Seven of 15 RCTs were at moderate risk of bias for all quality criteria and two studies were classified as having a high risk of bias. The recurrence rate of cancers resected with 5-ALA-based PDD was lower than of those resected using HAL-based PDD (odds ratio (OR) = 0.48, 95 % confidence interval (CI) [0.26–0.95]) but was not significantly different than those resected with NBI (OR = 0.53, 95 % CI [0.26–1.09]). The recurrence rate of cancers resected using HAL-based PDD versus NBI did not significantly differ (OR = 1.11, 95 % CI [0.55–2.1]). All cancers resected using 5-ALA-based PDD, HAL-based PDD, or NBI recurred at a lower rate than those resected using white light cystoscopy (WLC). No difference in progression rate was observed between cancers resected by all methods investigated.

Conclusions

The recurrence rate of some bladder cancers can be decreased by the implementation of either PDD- and NBI-assisted TUR; in real settings, clinicians should consider replacing WLC as the standard imaging technology to guide TUR.

α-Information-Based Registration of Dynamic Scans for Magnetic Resonance Cystography

To continue our effort on developing magnetic resonance (MR) cystography, we introduce a novel nonrigid 3-D registration method to compensate for bladder wall motion and deformation in dynamic MR scans, which are impaired by relatively low signal-to-noise ratio in each time frame. The registration method is developed on the similarity measure of α-information, which has the potential of achieving higher registration accuracy than the commonly used mutual information (MI) measure for either monomodality or multimodality image registration. The α-information metric was also demonstrated to be superior to both the mean squares and the cross-correlation metrics in multimodality scenarios. The proposed α-registration method was applied for bladder motion compensation via real patient studies, and its effect to the automatic and accurate segmentation of bladder wall was also evaluated. Compared with the prevailing MI-based image registration approach, the presented α-information-based registration was more effective to capture the bladder wall motion and deformation, which ensured the success of the following bladder wall segmentation to achieve the goal of evaluating the entire bladder wall for detection and diagnosis of abnormality.

Improving bladder cancer imaging using 3-T functional dynamic contrast-enhanced magnetic resonance imaging

OBJECTIVES

The objective of this study was to assess the capability of T2-weighted magnetic resonance imaging (T2W-MRI) and the additional diagnostic value of dynamic contrast-enhanced MRI (DCE-MRI) using multitransmit 3 T in the localization of bladder cancer.

MATERIALS AND METHODS

This prospective study was approved by the local institutional review board. Thirty-six patients were included in the study and provided informed consent. Magnetic resonance imaging scans were performed with T2W-MRI and DCE-MRI on a 3-T multitransmit system. Two observers (with 12 and 25 years of experience) independently interpreted T2W-MRI before DCE-MRI data (maps of pharmacokinetic parameters) to localize bladder tumors. The pathological examination of cystectomy bladder specimens was used as a reference criteria standard. The McNemar test was performed to evaluate the differences in sensitivity, specificity, and accuracy. Scores of κ were calculated to assess interobserver agreement.

RESULTS

The sensitivity, specificity, and accuracy of the localization with T2W-MRI alone were 81% (29/36), 63% (5/8), and 77% (34/44) for observer 1 and 72% (26/36), 63% (5/8), and 70% (31/44) for observer 2. With additional DCE-MRI available, these values were 92% (33/36), 75% (6/8), and 89% (39/44) for observer 1 and 92% (33/36), 63% (5/8), and 86% (38/44) for observer 2. Dynamic contrast-enhanced MRI significantly (P<0.01) improved the sensitivity and accuracy for observer 2. For the 23 patients treated with chemotherapy, DCE-MRI also significantly (P<0.02) improved the sensitivity and accuracy of bladder cancer localization with T2W-MRI alone for observer 2. Scores of κ were 0.63 for T2W-MRI alone and 0.78 for additional DCE-MRI. Of 7 subcentimeter malignant tumors, 4 (57%) were identified on T2W images and 6 (86%) were identified on DCE maps. Of 11 malignant tumors within the bladder wall thickening, 6 (55%) were found on T2W images and 10 (91%) were found on DCE maps.

CONCLUSIONS

Compared with conventional T2W-MRI alone, the addition of DCE-MRI improved interobserver agreement as well as the localization of small malignant tumors and those within bladder wall thickening.

Novel endoscopic diagnosis for bladder cancer

Advances in endoscopic imaging technology may improve sensitivity for the detection of bladder cancer and provide a more complete understanding of the urothelial landscape, and it also may lead to improved short-term and long-term cancer control. Fluorescence cystoscopy requires intravesical administration of a photosensitizing agent (5-aminolevulinic acid or hexaminolevulinate), and imaging with a blue-light endoscopy system demonstrably improves the detection of papillary and flat bladder lesions compared with conventional white-light cystoscopy. Prospective phase 3 clinical trials have demonstrated improved diagnostic ability, enhanced tumor resection, and a small but significant reduction in recurrence-free survival. Optical coherence tomography delineates subsurface microarchitecture information about bladder lesions in real time and has the ability to discriminate between noninvasive and invasive cancers. Narrow-band imaging may augment white-light cystoscopy by providing increased contrast between normal and abnormal tissue on the basis of neovascularity. Confocal laser endoscopy has been applied to the urinary tract using thinner probes adapted from use in gastrointestinal malignancies and provides exquisite images at microscopic resolution. More technology is on the horizon that may further enhance our ability to detect and accurately stage bladder tumors and distinguish benign from malignant or dysplastic lesions.

Real-time in vivo imaging of invasive- and biomaterial-associated bacterial infections using fluorescently labelled vancomycin

Invasive and biomaterial-associated infections in humans are often difficult to diagnose and treat. Here, guided by recent advances in clinically relevant optical imaging technologies, we explore the use of fluorescently labelled vancomycin (vanco-800CW) to specifically target and detect infections caused by Gram-positive bacteria. The application potential of vanco-800CW for real-time in vivo imaging of bacterial infections is assessed in a mouse myositis model and a human post-mortem implant model. We show that vanco-800CW can specifically detect Gram-positive bacterial infections in our mouse myositis model, discriminate bacterial infections from sterile inflammation in vivo and detect biomaterial-associated infections in the lower leg of a human cadaver. We conclude that vanco-800CW has a high potential for enhanced non-invasive diagnosis of infections with Gram-positive bacteria and is a promising candidate for early-phase clinical trials.

Combined use of fluorescence cystoscopy and cross-polarization OCT for diagnosis of bladder cancer and correlation with immunohistochemical markers

The combined use of fluorescence cystoscopy and cross-polarization optical coherence tomography (CP OCT) with quantitative estimation of the OCT signal was assessed in 92 bladder zones. It demonstrated the diagnostic accuracy in detecting superficial bladder cancer of 93.6%, sensitivity 96.4%, specificity 92.1%, positive predictive value 87% and negative predictive value 97.9%. Quantitative estimation of OCT signal standard deviation in cross-polarization (CP OCT SD index) makes the visual criteria of CP OCT image assessment more objective. The level of CP OCT SD index for diagnosing superficial bladder cancer, including cancer in situ, was 4.32 dB and lower. When tumor is located on a postoperative scar, CP OCT SD index may be higher than the threshold level of 4.32 dB due to strong scattering and depolarization in scar fibrous tissue. A high inverse correlation was found between CP OCT SD index and the level expressed by p63, Ki-67, p53, CD44v6 markers.

A unified EM approach to bladder wall segmentation with coupled level-set constraints

Magnetic resonance (MR) imaging-based virtual cystoscopy (VCys), as a non-invasive, safe and cost-effective technique, has shown its promising virtue for early diagnosis and recurrence management of bladder carcinoma. One primary goal of VCys is to identify bladder lesions with abnormal bladder wall thickness, and consequently a precise segmentation of the inner and outer borders of the wall is required. In this paper, we propose a unified expectation-maximization (EM) approach to the maximum-a posteriori (MAP) solution of bladder wall segmentation, by integrating a novel adaptive Markov random field (AMRF) model and the coupled level-set (CLS) information into the prior term. The proposed approach is applied to the segmentation of T(1)-weighted MR images, where the wall is enhanced while the urine and surrounding soft tissues are suppressed. By introducing scale-adaptive neighborhoods as well as adaptive weights into the conventional MRF model, the AMRF model takes into account the local information more accurately. In order to mitigate the influence of image artifacts adjacent to the bladder wall and to preserve the continuity of the wall surface, we apply geometrical constraints on the wall using our previously developed CLS method. This paper not only evaluates the robustness of the presented approach against the known ground truth of simulated digital phantoms, but further compares its performance with our previous CLS approach via both volunteer and patient studies. Statistical analysis on experts' scores of the segmented borders from both approaches demonstrates that our new scheme is more effective in extracting the bladder wall. Based on the wall thickness calibrated from the segmented single-layer borders, a three-dimensional virtual bladder model can be constructed and the wall thickness can be mapped onto the model, where the bladder lesions will be eventually detected via experts' visualization and/or computer-aided detection.

Motion correction for MR cystography by an image processing approach

Magnetic resonance (MR) cystography or MR-based virtual cystoscopy is a promising new technology to evaluate the entire bladder in a fully noninvasive manner. It requires the anatomical bladder images be acquired at high spatial resolution and with adequate signal-to-noise ratio (SNR). This often leads to a long-time scan (>5 min) and results in image artifacts due to involuntary bladder motion and deformation. In this paper, we investigated an image-processing approach to mitigate the problem of motion and deformation. Instead of a traditional single long-time scan, six repeated short-time scans (each of approximately 1 min) were acquired for the purpose of shifting bladder motion from intrascan into interscans. Then, the interscan motions were addressed by registering the short-time scans to a selected reference and finally forming a single average motion-corrected image. To evaluate the presented approach, three types of images were generated: 1) the motion-corrected image by registration and average of the short-time scans; 2) the directly averaged image of the short-time scans (without motion correction); and 3) the single image of the corresponding long-time scan. Six experts were asked to blindly score these images in terms of two important aspects: 1) the definition of the bladder wall and 2) the overall expression on the image quality. Statistical analysis on the scores suggested that the best result in both the aspects is achieved by the presented motion-corrected average. Furthermore, the superiority of the motion-corrected average over the other two is statistically significant by the measure of a linear mixed-effect model with p -values < 0.05. Our findings may facilitate the detection of bladder abnormality in MR cystography by mitigating the motion challenge. The effectiveness of this approach depends on the noise level of acquired short-time scans and the robustness of image registration, and future effort on these two aspects is needed.

New optical imaging technologies for bladder cancer: considerations and perspectives

PURPOSE

Bladder cancer presents as a spectrum of different diatheses. Accurate assessment for individualized treatment depends on initial diagnostic accuracy. Detection relies on white light cystoscopy accuracy and comprehensiveness. Aside from invasiveness and potential risks, white light cystoscopy shortcomings include difficult flat lesion detection, precise tumor delineation to enable complete resection, inflammation and malignancy differentiation, and grade and stage determination. Each shortcoming depends on surgeon ability and experience with the technology available for visualization and resection. Fluorescence cystoscopy/photodynamic diagnosis, narrow band imaging, confocal laser endomicroscopy and optical coherence tomography address the limitations and have in vivo feasibility. They detect suspicious lesions (photodynamic diagnosis and narrow band imaging) and further characterize lesions (optical coherence tomography and confocal laser endomicroscopy). We analyzed the added value of each technology beyond white light cystoscopy and evaluated their maturity to alter the cancer course.

MATERIALS AND METHODS

Detailed PubMed® searches were done using the terms "fluorescence cystoscopy," "photodynamic diagnosis," "narrow band imaging," "optical coherence tomography" and "confocal laser endomicroscopy" with "optical imaging," "bladder cancer" and "urothelial carcinoma." Diagnostic accuracy reports and all prospective studies were selected for analysis. We explored technological principles, preclinical and clinical evidence supporting nonmuscle invasive bladder cancer detection and characterization, and whether improved sensitivity vs specificity translates into improved correlation of diagnostic accuracy with recurrence and progression. Emerging preclinical technologies with potential application were reviewed.

RESULTS

Photodynamic diagnosis and narrow band imaging improve nonmuscle invasive bladder cancer detection, including carcinoma in situ. Photodynamic diagnosis identifies more papillary lesions than white light cystoscopy, enabling more complete resection and fewer residual tumors. Despite improved treatment current data on photodynamic diagnosis do not support improved high risk diathetic detection and characterization or correlation with disease progression. Prospective recurrence data are lacking on narrow band imaging. Confocal laser endomicroscopy and optical coherence tomography potentially grade and stage lesions but data are lacking on diagnostic accuracy. Several emerging preclinical technologies may enhance the diagnostic capability of endoscopic imaging.

CONCLUSIONS

New optical imaging technologies may improve bladder cancer detection and characterization, and transurethral resection quality. While data on photodynamic diagnosis are strongest, the clinical effectiveness of these technologies is not proven. Prospective studies are needed, particularly of narrow band imaging, confocal laser endomicroscopy and optical coherence tomography. As each technology matures and new ones emerge, cost-effectiveness analysis must be addressed in the context of the various bladder cancer types.

Diffusion-weighted magnetic resonance imaging in patients selected for radical cystectomy: detection rate of pelvic lymph node metastases

OBJECTIVE

To evaluate whether DW-MRI improves the detection of pelvic lymph nodes metastates in patients with bladder cancer undergoing radical cystectomy.

PATIENTS AND METHODS

36 patients with CT scan negative for nodal metastates underwent DW-MRI before surgery. Diagnostic accuracy of DW-MRI was compared with histopathological findings.

RESULTS

Mean ADC value was 0.85 × 10(-3) mm(3)/s in the nodal metastatic group and 1 × 10(-3) mm(3)/s in the nodal non-metastatic group (P = 0.02). The ADC cut-off value, obtained by the ROC curve was 0.86 × 10(-3) mm(3)/s. Patient-based sensitivity, specificity and positive and negative predictive values were 76.4%, 89.4%, 26.6%, and 71.4%, respectively.

CONCLUSION

DW-MRI may be used to differentiate metastatic from non-metastatic lymph nodes in patients with high-grade bladder cancer.

Cross-polarization optical coherence tomography for early bladder-cancer detection: statistical study

The capabilities of cross-polarization optical coherence tomography (CP OCT) for early bladder-cancer detection are assessed in statistical study and compared with the traditional OCT. Unlike the traditional OCT that demonstrates images only in copolarization, CP OCT acquires images in cross-polarization and copolarization simultaneously. 116 patients with localized flat suspicious lesions in the bladder were enrolled, 360 CP OCT images were obtained and analyzed. CP OCT demonstrated sensitivity 93.7% (vs. 81.2%, <0.0001), specificity 84% (vs. 70.0%, <0.001) and accuracy 85.3% (vs. 71.5%, <0.001) in detecting flat malignant bladder lesions, which is significantly better than with the traditional OCT. Higher diagnostic efficacy of CP OCT in detecting early bladder cancer is associated with the ability to detect changes in epithelium and connective tissues.

Fluorescence and white light cystoscopy for detection of carcinoma in situ of the urinary bladder

OBJECTIVES

To understand the additional benefits of HAL compared with conventional cystoscopy at the patient level and to explore relationships of urine cytology and CIS.

METHODS

We reanalyzed pooled data from 3 phase III studies comparing hexaminolevulinate (HAL, Hexvix) fluorescence cystoscopy with white light (WL) cystoscopy for detecting CIS.

RESULTS

Of 551 patients, 174 had at least one CIS lesion detected by HAL, WL, or random biopsy. The CIS detection rate of HAL was 0.87 vs. 0.75 for WL (P = 0.006). By multivariate Poisson regression, female patients had fewer CIS lesions (P < 0.0001) while older patients (≥ 65) had a higher number of CIS lesions detected by HAL (P = 0.04). HAL was less likely to detect CIS in patients previously treated with chemotherapy or BCG (P = 0.01 and 0.03, respectively), after adjusting for age. CIS was unifocal in 44% and multifocal in 56%. Multifocal CIS was associated with positive cytology more frequently than unifocal (65% vs. 45%; P = 0.016) whereas a negative cytology was more frequently associated with unifocal CIS. Patients with positive urine cytology had twice as many CIS lesions detected by HAL as patients with negative urine cytology (P = 0.02).

CONCLUSIONS

HAL cystoscopy had a higher CIS detection rate than WL cystoscopy. The average number of CIS lesions detected was associated with baseline clinical characteristics. Cytology was positive more frequently in multifocal CIS suggesting that HAL may be particularly useful in this setting to optimize detection of the extent of CIS.

Narrow-band imaging flexible cystoscopy: a new user's experience

BACKGROUND AND PURPOSE

We and others have demonstrated previously an improved detection rate for bladder cancer recurrences with narrow-band imaging (NBI) flexible cystoscopy when compared with conventional white-light imaging (WLI) flexible cystoscopy. We investigated whether a "new user" of NBI flexible cystoscopy, previously unfamiliar with this technique, could reproduce these results.

PATIENTS AND METHODS

The same protocol from our previous study was used by a new user (ZHS) for this second study at The Queen Elizabeth Hospital, Birmingham, United Kingdom. NBI flexible cystoscopy was performed on 23 patients with known recurrences of urothelial cancer (UC) of the bladder after initial conventional WLI flexible cystoscopy with the same switchable Olympus Lucera sequential red/green/blue instrument.

RESULTS

NBI detected 15 additional UCs in 8 of the 23 (35%) patients: Six of these patients had one additional UC, one had four additional UCs, and one had five additional UCs when compared with WLI, with a mean of 0.65 additional UCs per patient (standard deviation 1.30; Wilcoxon P = 0.01). When this second series is compared with our first published series, there is no statistical evidence that the excess number of UCs detected by NBI is different (Wilcoxon [unpaired] signed-rank test P = 0.74), which suggests that there is no difference between a new user and an experienced user in the application of NBI.

CONCLUSIONS

We and others continue to demonstrate a significantly improved detection rate of bladder UCs with NBI cystoscopy when compared with conventional WLI cystoscopy, even for new users previously unfamiliar with this technology.

Hexyl aminolevulinate fluorescence cystoscopy in bladder cancer

Although bladder cancer occurs frequently, early diagnosis and complete removal of malignant lesions usually lead to good clinical outcomes. In the USA, white light cystoscopy (WLC) is commonly used for bladder cancer diagnosis and guidance of the surgical resection. However, with WLC malignant and precancerous lesions may be missed, resulting in a high rate of disease recurrence. Monitoring for and treating these recurrences carry high direct and indirect costs. Because hexyl aminolevulinate (HAL; 5-ALA-hexylester) fluorescence cystoscopy has greater sensitivity than WLC, especially for detecting early stage lesions, and its use provides more complete resection and lower disease recurrence, it has been recommended in European clinical guidelines. This article reports our own HAL experiences and first time recurrence data, describes how HAL was developed, provides key clinical trial results, and discusses how HAL, which has revolutionized fluorescence cystoscopy and bladder cancer care in Europe, may ultimately revolutionize bladder cancer care in the USA.