New optical imaging technologies for bladder cancer: considerations and perspectives

Development and validation of a predictive model for the diagnosis of bladder tumors using narrow band imaging

PURPOSE

At present, the prediction of bladder tumor nature during cystoscopy is partially dependent on the clinician's own experience. Subjective factors may lead to excessive biopsy or delayed treatment. The purpose of our study is to establish a reliable model for predicting the nature of bladder tumors using narrow band imaging.

METHODS

From November 2021 to November 2022, the clinical data of 231 patients who required a cystoscopy were prospectively collected at our center. Cystoscopy was performed in 219 eligible patients, in which both tumor and vascular morphology characteristics were recorded. Pathological results were used as the diagnostic standard. A logistic regression analysis was used to screen out factors related to tumor pathology. Bootstrap resampling was used for internal validation. A total of 71 patients from four other centers served as an external validation cohort.

RESULTS

The following diagnostic factors were identified: tumor morphology (cauliflower-like or algae-like lesions), vascular morphology (dotted or circumferential vessels), tumor boundary (clear or unclear), and patients' symptoms (gross hematuria) and were included in the prediction model. The internal validation results showed that the area under the curve was 0.94 (95% CI 0.92-0.97), and the P value from the goodness-of-fit test was 0.97. After external validation, the results showed the area under the curve was 0.89 (95% CI 0.82-0.97) and the P value of the goodness-of-fit test was 0.24.

CONCLUSION

A diagnostic prediction nomogram was established for bladder cancer. The verification results showed that the prediction model has good prediction performance.

Diagnostic and therapeutic effects of fluorescence cystoscopy and narrow-band imaging in bladder cancer: a systematic review and network meta-analysis

BACKGROUND

This review aims to compare the efficacies of fluorescence cystoscopy, narrow-band imaging (NBI), and white light cystoscopy in the treatment and diagnosis of bladder cancer.

METHODS

The authors searched PubMed, EMbase, Web of Science, and the Cochrane Library from January 1990 to April 2022. A total of 26 randomized controlled studies and 22 prospective single-arm studies were selected. Most patients had nonmuscle-invasive bladder cancer. The study protocol has been registered at PROSPERO.

RESULTS

In the pairwise meta-analysis, 5-aminolevulinic acid (5-ALA) reduced the short-term and long-term recurrence rates of bladder cancer compared with white light cystoscopy (WLC); however, no statistical difference was observed in intermediate-term recurrence rates (RR=0.79, 95% CI: 0.57-1.09). Hexaminolevulinic acid and NBI reduced short-term, intermediate-term, and long-term recurrence rates. The sensitivity of 5-ALA, hexaminolevulinic acid, NBI, and WLC for bladder cancer were 0.89 (95% CI: 0.81-0.94), 0.96 (95% CI: 0.92-0.98), 0.96 (95% CI: 0.92-0.98), and 0.75 (95% CI: 0.70-0.79), respectively; however, only NBI had the same specificity as WLC (0.74 vs. 0.74). Compared with WLC, 5-ALA improved the detection rate of carcinoma in situ and Ta stage bladder cancer but had no advantage in T1 stage tumors (OR=2.39, 95% CI:0.79-7.19). Hexaminolevulinic acid and NBI improved the detection rates of all nonmuscular-invasive bladder cancers. In the network meta-analysis, there was no significant difference in either recurrence or detection rates between 5-ALA, hexaminolevulinic acid, and NBI.

CONCLUSION

Fluorescence cystoscopy and NBI are advantageous for treating and diagnosing patients with nonmuscle-invasive bladder cancer.

Optical imaging for early detection of cervical cancer: state of the art and perspectives

Significance

Cervical cancer is one of the major causes of death in females worldwide. HPV infection is the key cause of uncontrolled cell growth leading to cervical cancer. About 90% of cervical cancer is preventable because of the slow progression of the disease, giving a window of about 10 years for the precancerous lesion to be recognized and treated.

Aim

The present challenges for cervical cancer diagnosis are interobserver variation in clinicians' interpretation of visual inspection with acetic acid/visual inspection with Lugol's iodine, cost of cytology-based screening, and lack of skilled clinicians. The optical modalities can assist in qualitatively and quantitatively analyzing the tissue to differentiate between cancerous and surrounding normal tissues.

Approach

This work is on the recent advances in optical techniques for cervical cancer diagnosis, which promise to overcome the above-listed challenges faced by present screening techniques.

Results

The optical modalities provide substantial measurable information in addition to the conventional colposcopy and Pap smear test to clinically aid the diagnosis.

Conclusions

Recent optical modalities on fluorescence, multispectral imaging, polarization-sensitive imaging, microendoscopy, Raman spectroscopy, especially with the portable design and assisted by artificial intelligence, have a significant scope in the diagnosis of premalignant cervical cancer in future.

Preliminary study of the safety of acrinol in probe-based confocal laser endomicroscopy during transurethral resection of bladder tumors

We previously reported that probe-based confocal laser endomicroscopy using acrinol can depict cancerous nuclei. The objective of this study was to confirm the safety of acrinol in patients. For all seven patients, '50 ml' of a 0.1% acrinol and '1 ml' of 10% fluorescein in 99 ml of normal saline were introduced into the bladder. The laser probe adhered to the suspicious lesion from the working channel of the cystoscope. The patients underwent mucosal biopsy and transurethral resection after observation. Adverse events were noted during a valuation using common terminology criteria for adverse events version 4.0. Confocal laser endomicroscopy detected the nuclei of cancer cells in all seven patients. No adverse event was observed in any of the seven patients. Confocal laser endomicroscopy using acrinol as a novel dye can help visualize the cancerous nuclei of bladder urothelial carcinoma during cystoscopy without severe adverse events.

A clinical study of a CD44v6-targeted fluorescent agent for the detection of non-muscle invasive bladder cancer

BACKGROUND

Bladder cancer is the fifth most common malignancy in humans. Cystoscopy under white light imaging is the gold standard for bladder cancer diagnosis, but some tumors are difficult to visualize and can be overlooked, resulting in high recurrence rates. We previously developed a phage display-derived peptide-based near-infrared imaging probe, PLSWT7-DMI, which binds specifically to bladder cancer cells and is nontoxic to animals. Here, we report a clinical research of this probe for near-infrared fluorescence endoscopic detection of bladder cancer.

RESULTS

The purity, efficacy, safety, and nontoxicity of PLSWT7-DMI were confirmed prior to its clinical application. Twenty-two patients diagnosed with suspected non-muscle invasive bladder cancer were enrolled in the present study. Following intravesical administration of the probe, the entire mucosa was imaged under white and near-infrared imaging using an in-house developed endoscope that could switch between these two modes. The illuminated lesions under near-infrared light were biopsied and sent for histopathological examination. We observed a 5.1-fold increase in the fluorescence intensity in the tumor samples compared to normal tissue, and the probe demonstrated a sensitivity and specificity of 91.2% and 90%, respectively. Common diagnostic challenges, such as small satellite tumors, carcinoma in situ, and benign suspicious mucosa, were visualized and could be distinguished from cancer. Furthermore, no adverse effects were observed in humans. These first-in-human results indicate that PLSWT7-DMI-based near-infrared fluorescence endoscopy is a safe and effective approach for the improved detection of bladder cancer, and may enable thorough resection to prevent recurrence.

Enhanced Visualization Methods for First Transurethral Resection of Bladder Tumour in Suspected Non-muscle-invasive Bladder Cancer: A Health Technology Assessment

BACKGROUND

Bladder cancer begins in the innermost lining of the bladder wall and, on histological examination, is classified as one of two types: non-muscle-invasive bladder cancer (NMIBC) or muscle-invasive bladder cancer. Transurethral resection of bladder tumour (TURBT) is the standard treatment for people with NMIBC, but the high rate of cancer recurrence after first TURBT is a challenge that physicians and patients face. Tumours seen during follow-up may have been missed or incompletely resected during first TURBT. TURBT is conventionally performed using white light to see the tumours. However, small papillary or flat tumours may be missed with the use of white light alone. With the emergence of new technologies to improve visualization during TURBT, better diagnostic and patient outcomes may be expected. We conducted a health technology assessment of two enhanced visualization methods, both as an adjunct to white light to guide first TURBT for people with suspected NMIBC-hexaminolevulinate hydrochloride (HAL), a solution that is instilled into the bladder to make tumours fluoresce under blue-violet light, and narrow band imaging (NBI), a technology that filters light into wavelengths that can be absorbed by hemoglobin in the tumours, making them appear darker. Our assessment included an evaluation of effectiveness, safety, cost-effectiveness, and the budget impact of publicly funding these new technologies to improve patient outcomes following first TURBT. The use of NBI in diagnostic cystoscopy was out of scope for this health technology assessment.

METHODS

We performed a systematic literature search of the clinical evidence from inception to April 15, 2020. We searched for randomized controlled trials (RCTs) that compared the outcomes of first TURBT with the use of HAL or NBI, both as an adjunct to white light, with the outcomes of first TURBT using white light alone, or studies that made such comparison between HAL and NBI. We conducted pairwise meta-analyses using a fixed effects model where head-to-head comparisons were available. In the absence of any published RCT for comparison between HAL and NBI, we indirectly compared the two technologies through indirect treatment comparison (ITC) analysis. We assessed the risk of bias of each included study using the Cochrane risk-of-bias tool. We assessed the quality of the body of evidence according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria. We performed a systematic economic literature search and conducted a cost-utility analysis with a 15-year time horizon from a public payer perspective. We also analyzed the budget impact of publicly funding HAL and NBI as an adjunct to white light in people undergoing their first TURBT for suspected non-muscle-invasive bladder cancer in Ontario.

RESULTS

In the clinical evidence review, we identified 8 RCTs that used HAL or NBI as an adjunct to white light during first TURBT. Pairwise meta-analysis of HAL studies showed that HAL-guided TURBT as an adjunct to white light significantly reduces recurrence rate at 12 months compared with TURBT using white light alone (risk ratio 0.70, 95% confidence interval [CI] 0.51-0.95) (GRADE: Moderate). Five-year recurrence-free survival was significantly higher when HAL was used as an adjunct to white light than when white light was used alone (GRADE: Moderate). There was little to no difference in the tumour progression rate (GRADE: Moderate).Meta-analysis of NBI studies did not show a significant difference between NBI-guided TURBT as an adjunct to white light and TURBT using white light alone in reducing the rate of recurrence at 12 months (risk ratio 0.94, 95% CI 0.75-1.19) (GRADE: Moderate). No evidence on the effect on recurrence-free survival or tumour progression rate was identified for NBI-guided TURBT. The indirect estimate from the network analysis showed a trend toward a lower rate of recurrence after HAL-guided TURBT than after NBI-guided TURBT but the difference was not statistically significant (risk ratio 0.76, 95% CI 0.51-1.11) (GRADE: Low). Studies showed that use of HAL or NBI during TURBT was generally safe.The incremental cost-effectiveness ratio of HAL-guided TURBT compared with NBI-guided TURBT, both as an adjunct to white light, is $12,618 per quality-adjusted life-year (QALY) gained. Compared with TURBT using white light alone and using adjunct NBI, the probability of HAL-guided TURBT being cost-effective is 69.1% at a willingness-to-pay value of $50,000 per QALY gained and 74.6% at a willingness-to-pay of $100,000 per QALY gained. The annual budget impact of publicly funding HAL-guided TURBT in Ontario over the next 5 years ranges from an additional $0.6 million in year 1 to $2.5 million in year 5.

CONCLUSIONS

First TURBT guided by HAL as an adjunct to white light likely reduces the rate of recurrence at 12 months and increases 5-year recurrence-free survival when compared with first TURBT using white light alone. There is likely little to no difference in the tumour progression rate. First TURBT guided by NBI as an adjunct to white light likely results in little to no difference in the rate of recurrence at 12 months when compared with first TURBT using white light alone. Based on an indirect comparison, there may be little to no difference in cancer recurrence rate between HAL-guided and NBI-guided first TURBT. Use of HAL or NBI during first TURBT is generally safe. For people undergoing their first TURBT for suspected non-muscle-invasive bladder cancer, using HAL as an adjunct to white light is likely to be cost-effective compared with using white light alone or with using NBI as an adjunct to white light. We estimate that publicly funding HAL as an adjunct to white light to guide first TURBT for people in Ontario with suspected NMIBC would result in additional costs of between $0.6 million and $2.5 million per year over the next 5 years.

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.

NBI utility in oncologic surgery: An organ by organ review

The main aims of the oncologic surgeon should be an early tumor diagnosis, complete surgical resection, and a careful post-treatment follow-up to ensure a prompt diagnosis of recurrence. Radiologic and endoscopic methods have been traditionally used for these purposes, but their accuracy might sometimes be suboptimal. Technological improvements could help the clinician during the diagnostic and therapeutic management of tumors. Narrow band imaging (NBI) belongs to optical image techniques, and uses light characteristics to enhance tissue vascularization. Because neoangiogenesis is a fundamental step during carcinogenesis, NBI could be useful in the diagnostic and therapeutic workup of tumors. Since its introduction in 2001, NBI use has rapidly spread in different oncologic specialties with clear advantages. There is an active interest in this topic as demonstrated by the thriving literature. It is unavoidable for clinicians to gain in-depth knowledge about the application of NBI to their specific field, losing the overall view on the topic. However, by looking at other fields of application, clinicians could find ideas to improve NBI use in their own specialty. The aim of this review is to summarize the existing literature on NBI use in oncology, with the aim of providing the state of the art: we present an overview on NBI fields of application, results, and possible future improvements in the different specialties.

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.

Evaluation of autofluorescence and photodynamic diagnosis in assessment of bladder lesions

The ability to detect and diagnose bladder cancer early and precisely is crucial for effective treatment. The aim of this study is to assess the utility of optical biopsy performed with autofluorescence cystoscopy (AFC) using the Onco-LIFE system with numerical color values (NCVs) and by ALA/PDD. Histopathological examination of material obtained during TURBT and/or biopsy of the bladder was carried out in 251 patients. In the case of 35 patients, the selection of the specimen collected for histopathological examination was based using ALA/PDD. In the remaining 216 patients, tissue was collected based on the findings of AFC with NCV. Using AFC, the observed NCV ranged from 0 to 3.86; the highest mean NCV was observed in neoplastic muscle invasive lesions and was equal to 3.18. Furthermore, non-muscle invasive tumors were characterized by a mean NCV equal to 1.54. Tissue with inflammation, metaplasia, and healthy tissue demonstrated significantly lower mean NCV values. The presence of a muscle-invasive tumor increased the NCV by approximately 2.86 compared to healthy tissue. The rates of postoperative complications depend on the examining operator and are observed more often, as much as 65.7 % during ALA/PDD. AFC with NCV using the Onco-LIFE system, as well as ALA/PDD are helpful tools for early diagnosis of bladder precancerous and cancer lesions and for performing targeted biopsies. A significant correlation was found between lesion NCV index and the grade of dysplasia or tumor malignancy. Tissue with inflammation, metaplasia, and healthy tissue demonstrated significantly lower mean NCV values. AFE with NCV have a significantly higher sensitivity than specificity. Low rates of postoperative complications are correlated to the experience of the endoscopist and with AFE/NCV in comparison of ALA/PDD.

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

Objective

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

Methods

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

Results

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

Conclusion

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

Detection of carcinogen-induced bladder cancer by fluorocoxib A

BACKGROUND

Conventional cystoscopy can detect advanced stages of bladder cancer; however, it has limitations to detect bladder cancer at the early stages. Fluorocoxib A, a rhodamine-conjugated analog of indomethacin, is a novel fluorescent imaging agent that selectively targets cyclooxygenase-2 (COX-2)-expressing cancers.

METHODS

In this study, we have used a carcinogen N-butyl-N-4-hydroxybutyl nitrosamine (BBN)-induced bladder cancer immunocompetent mouse B6D2F1 model that resembles human high-grade invasive urothelial carcinoma. We evaluated the ability of fluorocoxib A to detect the progression of carcinogen-induced bladder cancer in mice. Fluorocoxib A uptake by bladder tumors was detected ex vivo using IVIS optical imaging system and Cox-2 expression was confirmed by immunohistochemistry and western blotting analysis. After ex vivo imaging, the progression of bladder carcinogenesis from normal urothelium to hyperplasia, carcinoma-in-situ and carcinoma with increased Ki67 and decreased uroplakin-1A expression was confirmed by histology and immunohistochemistry analysis.

RESULTS

The specific uptake of fluorocoxib A correlated with increased Cox-2 expression in progressing bladder cancer. In conclusion, fluorocoxib A detected the progression of bladder carcinogenesis in a mouse model with selective uptake in Cox-2-expressing bladder hyperplasia, CIS and carcinoma by 4- and 8-fold, respectively, as compared to normal bladder urothelium, where no fluorocoxib A was detected.

CONCLUSIONS

Fluorocoxib A is a targeted optical imaging agent that could be applied for the detection of Cox-2 expressing human bladder cancer.

Optical and Cross-Sectional Imaging Technologies for Bladder Cancer

Optical and cross-sectional imaging plays critical roles in bladder cancer diagnostics. White light cystoscopy remains the cornerstone for the management of non-muscle-invasive bladder cancer. In the last decade, significant technological improvements have been introduced for optical imaging to address the known shortcomings of white light cystoscopy. Enhanced cystoscopy modalities such as blue light cystoscopy and narrowband imaging survey a large area of the urothelium and provide contrast enhancement to detect additional lesions and decrease cancer recurrence. However, higher false-positive rates accompany the gain of sensitivity. Optical biopsy technologies, including confocal laser endomicroscopy and optical coherence tomography, provide cellular resolutions combined with subsurface imaging, thereby enabling optical-based cancer characterization, and may lead to real-time cancer grading and staging. Coupling of fluorescently labeled binding agents with optical imaging devices may translate into high molecular specificity, thus enabling visualization and characterization of biological processes at the molecular level. For cross-sectional imaging, upper urinary tract evaluation and assessment potential extravesical tumor extension and metastases are currently the primary roles, particularly for management of muscle-invasive bladder cancer. Multi-parametric MRI, including dynamic gadolinium-enhanced and diffusion-weighted sequences, has been investigated for primary bladder tumor detection. Ultrasmall superparamagnetic particles of iron oxide (USPIO) are a new class of contrast agents that increased the accuracy of lymph node imaging. Combination of multi-parametric MRI with positron emission tomography is on the horizon to improve accuracy rates for primary tumor diagnostics as well as lymph node evaluation. As these high-resolution optical and cross-sectional technologies emerge and develop, judicious assessment and validation await for their clinical integration toward improving the overall management of bladder cancer.

Methods for bladder cancer diagnosis - The role of autofluorescence and photodynamic diagnosis

Bladder cancer is one of the most common Genito-urinary malignant tumors in humans. Improved diagnostic and therapeutic methods that aim to reduce rates of recurrence and progression of bladder cancer are needed. In current publications, one can find information on such methods as Raman spectroscopy, ultraviolet autofluorescence microscopy, confocal laser endoscopy, photoacoustic imaging, molecular imaging, multi-photon microscopy and many other new diagnostic techniques. These methods do not show significant adverse effects and are procedures well tolerated by patients as they use mostly physical phenomena that are neutral towards the human body. This review highlights the techniques of autofluorescence (AF) or laser induced fluorescence (LIF) and photodynamic diagnostics (PDD) which have been widely clinically studied for many years as a complement to cystoscopy. These methods can be performed during standard cystoscopy and they can be used in routine practice. This review shows that Autofluorescent and Photodynamic diagnostics are effective and have great potential in enhancing the diagnosis of bladder cancer. However, more research should be performed to help realize their full potential.

Surface-Enhanced Raman Scattering Nanoparticles for Multiplexed Imaging of Bladder Cancer Tissue Permeability and Molecular Phenotype

Bladder cancer has the highest recurrence rate of all cancers due in part to inadequate transurethral resection. Inadequate resection is caused by the inability of cystoscopes to detect invisible lesions during the resection procedure. To improve detection and resection of nonmuscle invasive bladder cancer, we quantified the ability of a surface-enhanced Raman nanoparticle and endoscope system to classify bladder tissue as normal or cancerous. Both antibody-based (active) and tissue permeability-based (passive) targeting mechanisms were evaluated by topically applying nanoparticles to ex vivo human bladder tissue samples. Multiplexed molecular imaging of CD47 and Carbonic Anhydrase 9 tumor proteins gave a receiver operating characteristic area under the curve (ROC AUC of 0.93 (0.75, 1.00). Furthermore, passively targeted nanoparticles enabled tissue classification with an ROC AUC of 0.93 (0.73, 1.00). Passively targeted nanoparticles penetrated 5-fold deeper and bound to tumor tissue at 3.3-fold higher concentrations in cancer compared to normal bladder urothelium, suggesting the existence of an enhanced surface permeability and retention effect in human bladder cancer.

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.

Perspective review of what is needed for molecular-specific fluorescence-guided surgery

Molecular image-guided surgery has the potential for translating the tools of molecular pathology to real-time guidance in surgery. As a whole, there are incredibly positive indicators of growth, including the first United States Food and Drug Administration clearance of an enzyme-biosynthetic-activated probe for surgery guidance, and a growing number of companies producing agents and imaging systems. The strengths and opportunities must be continued but are hampered by important weaknesses and threats within the field. A key issue to solve is the inability of macroscopic imaging tools to resolve microscopic biological disease heterogeneity and the limitations in microscopic systems matching surgery workflow. A related issue is that parsing out true molecular-specific uptake from simple-enhanced permeability and retention is hard and requires extensive pathologic analysis or multiple in vivo tests, comparing fluorescence accumulation with standard histopathology and immunohistochemistry. A related concern in the field is the over-reliance on a finite number of chosen preclinical models, leading to early clinical translation when the probe might not be optimized for high intertumor variation or intratumor heterogeneity. The ultimate potential may require multiple probes, as are used in molecular pathology, and a combination with ultrahigh-resolution imaging and image recognition systems, which capture the data at a finer granularity than is possible by the surgeon. Alternatively, one might choose a more generalized approach by developing the tracer based on generic hallmarks of cancer to create a more "one-size-fits-all" concept, similar to metabolic aberrations as exploited in fluorodeoxyglucose - positron emission tomography (FDG-PET) (i.e., Warburg effect) or tumor acidity. Finally, methods to approach the problem of production cost minimization and regulatory approvals in a manner consistent with the potential revenue of the field will be important. In this area, some solid steps have been demonstrated in the use of fluorescent labeling commercial antibodies and separately in microdosing studies with small molecules.

Phage Display-Derived Peptide-Based Dual-Modality Imaging Probe for Bladder Cancer Diagnosis and Resection Postinstillation: A Preclinical Study

Bladder cancer is a common human malignancy. Conventional ultrasound and white-light cystoscopy are often used for bladder cancer diagnosis and resection, but insufficient specificity results in a high bladder cancer recurrence rate. New strategies for the diagnosis and resection of bladder cancer are needed. In this study, we developed a highly specific peptide-based probe for bladder cancer photoacoustic imaging (PAI) diagnosis and near-infrared (NIR)-imaging-guided resection after instillation. A bladder cancer-specific peptide (PLSWT7) was selected by in vivo phage-display technology and labeled with IRDye800CW to synthesize a bladder cancer-specific dual-modality imaging (DMI) probe (PLSWT7-DMI). The feasibility of PLSWT7-DMI-based dual-modality PAI-NIR imaging was assessed in vitro, in mouse models, and ex vivo human bladders. An air-pouch bladder cancer (APBC) model suitable for probe instillation was established to evaluate the probe-based bladder cancer PAI diagnosis and NIR-imaging-guided resection. Human bladders were used to assess whether the PLSWT7-DMI-based DMI strategy is a translatable approach for bladder cancer detection and resection. The probe exhibited excellent selectivity and specificity both in vitro and in vivo Postinstillation of the probe, tumors <3 mm were detectable by PAI, and NIR-imaging-guided tumor resection decreased the bladder cancer recurrence rate by 90% and increased the survival in the mouse model. Additionally, ex vivo NIR imaging of human bladders indicated that PLSWT7-DMI-based imaging would potentially allow precise resection of bladder cancer in clinical settings. This PLSWT7-DMI-based DMI strategy was a translatable approach for bladder cancer diagnosis and resection and could potentially lower the bladder cancer recurrence rate. Mol Cancer Ther; 17(10); 2100-11. ©2018 AACR.

Narrow Band Imaging reduces persistence of cancer in patients with pT1 high grade bladder cancer

PURPOSE

To evaluate persistence rate on repeated transurethral resection of the bladder (re-TURB) 6 weeks after the first TURB in patients with pT1HG disease undergoing resection of the margins and bed on Narrow Band Imaging.

MATERIALS AND METHODS

A consecutive series of patients undergoing TURB and a diagnosis of pT1 high grade disease were prospectively enrolled. On initial TURB patients underwent classic white light resection of the tumour followed by narrow band image (NBI) resection of margins and bed. After 6 weeks from the initial TURB, patients underwent a re-TURB under white light. Persistence rates on re-TURB were recorded.

RESULTS

Overall 797 patients underwent TURB, out of them 126 patients with pT1 high grade disease were included in the study. The total number of lesions was 226 meaning 1.79 lesions per patient. On re-TURB 24/126 (19%) of the patients presented residual disease with a total of 28/226 (12%) lesions identified. All these patients presented a pTa residual disease. Out of them 8/21 (38%) presented bladder cancer on the resection bed and 13/21 (62%) presented bladder cancer on margins.

CONCLUSION

Narrow Band Imaging trans-urethral resection of the bladder is an oncological effective procedure in the treatment of pT1HG disease. The procedure has a 19% of persistence rate which is inferior when compared to the available evidence on white light TURB. Further multicenter studies are needed in order to validate our results.

Probe-Based Confocal Laser Endomicroscopy Using Acrinol as a Novel Dye Can Be Used to Observe Cancer Nuclei of Bladder Carcinoma In Situ

Background: Cystoscopy using white light is a standard procedure for diagnosing bladder cancer; however, white light can result in missed lesions that are present, but not visible, such as in cases of carcinoma in situ (CIS). In this case report, we describe observing the nuclei of urothelial carcinoma cells in situ that were not visible with cystoscopy under white light using probe-based confocal laser endomicroscopy (pCLE) with acrinol and fluorescein during transurethral resection of a bladder tumor (TURBT). Case Presentation: A 59-year-old male with a medical history of neurogenic bladder dysfunction with multiple bladder diverticula was referred to the urology department for gross hematuria. TURBT was performed with the assistance of pCLE, using acrinol as a novel dye. Standard cystoscopy under white light could not detect any bladder tumor; however, pCLE using acrinol could detect the abnormal nuclei of bladder CIS. Subsequent histopathologic analysis of the specimen confirmed a diagnosis of bladder CIS. To our knowledge, this is the first reported case of bladder CIS diagnosed with the assistance of pCLE using acrinol in a patient undergoing a TURBT. Conclusion: pCLE using acrinol as a novel dye can help observe the cancerous nuclei of bladder CIS that cannot be detected using conventional cystoscopy under white light. Therefore, pCLE using acrinol is one possible modality for performing an optical biopsy during TURBT.

Real-time in-vivo microscopic imaging of the cervix using confocal laser endomicroscopy: preliminary observations and feasibility study

Confocal laser endomicroscopy (CLE) enables in-vivo, real-time, imaging of tissues with a micron-scale resolution through a fiber optic probe. CLE could be a valuable tool for the detection and characterization of suspicious (dysplastic) areas on the uterine cervix in a minimally invasive manner. This study evaluates the technical feasibility and safety of CLE on the cervix. The study also aims to create a preliminary iconography of normal and dysplastic squamous and columnar cervical epithelium. In-vivo CLE was performed on nine patients scheduled for a cervical loop electric excision procedure for high-grade superficial intraepithelial lesions. The CLE images were compared with standard hematoxylin and eosin analysis of loop electric excision procedure specimens. The histopathological diagnosis on the surgical specimen was established as per standard of care. CLE images were then reviewed by pathologists to point out specific histopathological features. pCLE of the exocervix and the transformation zone was performed successfully on seven out of nine patients. Uninterpretable images were obtained in two other cases: one using the AlveoFlex and one using the GastroFlex UHD after the application of acetic acid 2%. A total of 82.5% of the sequences recorded with the GastroFlex were suitable for interpretation. No adverse event or complications occurred. CLE enables proper in-vivo imaging of healthy and dysplastic cervical tissue. Images correlate well with the histopathological features established through traditional histology. Future blinded prospective analysis will determine the reliability of the real-time diagnosis and its potential use in the assessment and treatment of cervical lesions.

Can bladder preservation therapy come to the center stage?

Decision-making in urological cancer care requires a multidisciplinary approach for refinement, but its impact on urothelial carcinoma of the bladder has not been fully addressed for the past three decades, except for the latest immunological checkpoint inhibitor approved by the U.S. Food and Drug Administration for metastatic muscle-invasive bladder cancer that is resistant to platinum-based chemotherapy. For the time being, radical cystectomy is the gold standard of curative therapy for muscle-invasive bladder cancer. Trimodal therapy that combines chemotherapy for the purpose of radiation sensitization, external beam radiotherapy and transurethral resection of bladder tumor has emerged as a potential alternative treatment option that preserves the bladder. In lack of randomized studies for bladder preservation therapy compared with surgery, the principles of management of urothelial carcinoma of the bladder have evolved in recent times, with an emphasis on bladder preservation. A number of bladder preservation techniques are available to the surgeon; however, appropriately selected patients with muscle-invasive bladder cancer should be offered the opportunity to discuss various treatment options, including organ-sparing trimodal therapy. The aim of the present study was to compare the primary outcomes of the available treatment methods and identify the sources of variance among studies. A review of various bladder preservation techniques in vogue for the management of urothelial carcinoma of the bladder is discussed.

In vivo biodistribution and toxicity of intravesical administration of quantum dots for optical molecular imaging of bladder cancer

Optical molecular imaging holds the potential to improve cancer diagnosis. Fluorescent nanoparticles such as quantum dots (QD) offer superior optical characteristics compared to organic dyes, but their in vivo application is limited by potential toxicity from systemic administration. Topical administration provides an attractive route for targeted nanoparticles with the possibility of minimizing exposure and reduced dose. Previously, we demonstrated successful ex vivo endoscopic imaging of human bladder cancer by topical (i.e. intravesical) administration of QD-conjugated anti-CD47. Herein we investigate in vivo biodistribution and toxicity of intravesically instilled free QD and anti-CD47-QD in mice. In vivo biodistribution of anti-CD47-QD was assessed with inductively coupled plasma mass spectrometry. Local and systemic toxicity was assessed using blood tests, organ weights, and histology. On average, there was no significant accumulation of QD outside of the bladder, although in some mice we detected extravesical biodistribution of QD suggesting a route for systemic exposure under some conditions. There were no indications of acute toxicity up to 7 days after instillation. Intravesical administration of targeted nanoparticles can reduce systemic exposure, but for clinical use, nanoparticles with established biosafety profiles should be used to decrease long-term toxicity in cases where systemic exposure occurs.

Proceedings of the 3rd Annual Albert Institute for Bladder Cancer Research Symposium

The Third Annual Albert Institute Bladder Symposium was held on September 8–10th, 2016, in Denver Colorado. Participants discussed several critical topics in the field of bladder cancer: 1) Best practices for tissue analysis and use to optimize correlative studies, 2) Modeling bladder cancer to facilitate understanding and innovation, 3) Targeted therapies for bladder cancer, 4) Tumor phylogeny in bladder cancer, 5) New Innovations in bladder cancer diagnostics. Our understanding of and approach to treating urothelial carcinoma is undergoing rapid advancement. Preclinical models of bladder cancer have been leveraged to increase our basic and mechanistic understanding of the disease. With the approval of immune checkpoint inhibitors for the treatment of advanced urothelial carcinoma, the treatment approach for these patients has quickly changed. In this light, molecularly-defined subtypes of bladder cancer and appropriate pre-clinical models are now essential to the further advancement and appropriate application of these therapeutic improvements. The optimal collection and processing of clinical urothelial carcinoma tissues samples will also be critical in the development of predictive biomarkers for therapeutic selection. Technological advances in other areas including optimal imaging technologies and micro/nanotechnologies are being applied to bladder cancer, especially in the localized setting, and hold the potential for translational impact in the treatment of bladder cancer patients. Taken together, advances in several basic science and clinical areas are now converging in bladder cancer. These developments hold the promise of shaping and improving the clinical care of those with the disease.

Image-Guided Transurethral Resection of Bladder Tumors - Current Practice and Future Outlooks

Transurethral resection of bladder tumor (TURBT) under white light cystoscopy (WLC) is the cornerstone for the diagnosis, removal and local staging of non-muscle invasive bladder cancer (NMIBC). Despite technological improvements over the decades, significant shortcomings remain with WLC for tumor detection, thereby impacting the surgical quality and contributing to tumor recurrence and progression. Enhanced cystoscopy modalities such as blue light cystoscopy (BLC) and narrow band imaging (NBI) aid resections by highlighting tumors that might be missed on WLC. Optical biopsy technologies such as confocal laser endomicroscopy (CLE) and optical coherence tomography (OCT) characterize tissue in real-time to ensure a more thorough resection. New resection techniques, particularly en bloc resection, are actively under investigation to improve the overall quality of resections and aid pathologic interpretation. Moreover, new image processing computer algorithms may improve perioperative planning and longitudinal follow-up. Clinical translation of molecular imaging agents is also on the horizon to improve optical diagnosis of bladder cancer. This review focuses on emerging technologies that can impact the quality of TURBT to improve the overall management of NMIBC.

Dynamic real-time in vivo confocal laser endomicroscopy of the fallopian tube during laparoscopy in the prevention of ovarian cancer

OBJECTIVES

Recently it has been postulated that most ovarian cancers have a tubal origin. The identification of preinvasive tubal lesions would be of great interest in the early diagnosis of ovarian cancer. Optical biopsy has been developed and validated in the detection of precancerous lesions (such as Barrett's oesophagus). The first objective of this study was to assess the feasibility of optical biopsy in the study of fallopian tubes during laparoscopy. The second objective was to describe the images in benign premalignant and malignant tubes with a histopathological and immunohistochemical (p53 and Ki67 expressions) correlation.

STUDY DESIGN

In this prospective study, 40 patients undergoing laparoscopic salpingectomy for benign conditions (benign hysterectomy), prophylactic conditions (BRCA mutation) or in case of pelvic cancers were included after obtaining informed and signed consent prior to surgery. The optical biopsy was performed on the fimbria of each tube in and ex vivo. A correlation was made with the histopathological and immunohistochemical analysis.

RESULTS

The feasibility of optical biopsy was always confirmed during laparoscopy. The optical biopsy iconography revealed different images in benign tubal epithelium (well-defined black and grey structure), in adenomatoid tumour (tortuous architectural organization), in STIC precancerous lesion (enlarged, irregular and pleomorphic cells, dilated and distorted vessels) and in tubal metastasis of high grade serous ovarian cancer (dark neoplastic cells irregular in size and shape) CONCLUSIONS: Optical biopsy may be the first emerging mini-invasive technology that could detect tubal lesions and may be considered as a promising tool in the early detection of ovarian cancer.

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.

Narrow band imaging for bladder cancer

Narrow band imaging (NBI) is a newly developed technology aiming to provide additional endoscopic information for patients with bladder cancer. This review focuses on the diagnostic accuracy and treatment outcome using NBI cystoscopy for the treatment of non-muscle invasive bladder cancer. Current results showed improved sensitivity of NBI cystoscopy compared to conventional white light cystoscopy, although lower specificity and increased false-positive results were reported using NBI cystoscopy. The treatment outcome using NBI technology in transurethral resection of bladder tumor had a positive impact while decreased number of residual tumors and tumor recurrence at follow-up were reported. In the future, the application of NBI technology might refine the treatment and follow-up protocol in patients with non-muscle invasive bladder cancer. However, this large scale prospective studies are required to confirm the real cost-effectiveness of this new technology.

A new non-muscle-invasive bladder tumor-homing peptide identified by phage display in vivo

Bladder cancer is common and widespread, and its incidence is increasing. Many new diagnostic methods combined with state-of-the-art technology have been introduced in cystoscopy to collect real-time images of the bladder mucosa for diagnosis, but often miss inconspicuous early-stage tumors. Fluorophore-labeled peptides with high sensitivity and specificity for cancer would be a desirable tool for the detection and treatment of tiny or residual bladder tumors. Phage display and the human non-muscle-invasive bladder cancer cell line BIU-87 were used to identify a peptide. The isolated phage display peptide (CSSPIGRHC, named NYZL1) was tested in vitro for its binding specificity and affinity. Accumulation into xenograft tumors in a nude mouse model was analyzed with FITC-labeled NYZL1. NYZL1, with strong tumor-homing ability, was identified by in vivo phage library selection in the bladder cancer model. The NYZL1 phage and synthetic FITC-labeled NYZL1 peptides bound to tumor tissues and cells, but were hardly detected in normal control organs. Notably, accumulation of FITC-NYZL1 in bladder tumor cells was time-dependent. Biodistribution studies of xenografts of BIU-87 cells showed accumulation of injected FITC-NYZL1 in the tumors, and the bound peptide could not be removed by perfusion after 24 h. The mouse model of bladder tumor showed increased fluorescence intensity in the tumor-bearing bladder in comparison with normal bladder tissues after 4–6 h. In conclusion, NYZL1 may represent a lead peptide structure applicable in the development of optical molecular imaging.

Nanotechnology and cancer: improving real-time monitoring and staging of bladder cancer with multimodal mesoporous silica nanoparticles

Background

Despite being one of the most common cancers, bladder cancer is largely inefficiently and inaccurately staged and monitored. Current imaging methods detect cancer only when it has reached “visible” size and has significantly disrupted the structure of the organ. By that time, thousands of cells will have proliferated and perhaps metastasized. Repeated biopsies and scans are necessary to determine the effect of therapy on cancer growth. In this report, we describe a novel approach based on multimodal nanoparticle contrast agent technology and its application to a preclinical animal model of bladder cancer. The innovation relies on the engineering core of mesoporous silica with specific scanning contrast properties and surface modification that include fluorescence and magnetic resonance imaging (MRI) contrast. The overall dimensions of the nano-device are preset at 80–180 nm, depending on composition with a pore size of 2 nm.

Methods

To facilitate and expedite discoveries, we combined a well-known model of bladder cancer and our novel technology. We exposed nanoparticles to MB49 murine bladder cancer cells in vitro and found that 70 % of the cells were labeled by nanoparticles as measured by flow cytometry. The in vivo mouse model for bladder cancer is particularly well suited for T1- and T2-weighted MRI.

Results

Under our experimental conditions, we demonstrate that the nanoparticles considerably improve tumor definition in terms of volumetric, intensity and structural characteristics. Important bladder tumor parameters can be ascertained, non-invasively, repetitively, and with great accuracy. Furthermore, since the particles are not biodegradable, repetitive injection is not required. This feature allows follow-up diagnostic evaluations during cancer treatment. Changes in MRI signals show that in situ uptake of free particles has predilection to tumor cells relative to normal bladder epithelium. The particle distribution within the tumors was corroborated by fluorescent microscopy of sections of excised bladders. In addition, MRI imaging revealed fibrous finger-like projections into the tumors where particles insinuated themselves deeply. This morphological characteristic was confirmed by fluorescence microscopy.

Conclusions

These findings may present new options for therapeutic intervention. Ultimately, the combination of real-time and repeated MRI evaluation of the tumors enhanced by nanoparticle contrast may have the potential for translation into human clinical studies for tumor staging, therapeutic monitoring, and drug delivery.

Review of current optical diagnostic techniques for non-muscle-invasive bladder cancer

Introduction

Urinary bladder urothelial cell carcinoma is one of the most commonly diagnosed cancers in Europe. After prostate, lung and colon cancers, bladder cancer rates as the fourth most common cancer in men in the world.

Urinary bladder cancer detection, treatment, and staging have traditionally been based on an endoscopic examination – cystoscopy.

Material and methods

A Medline, and Web of Science database search was performed on September 2015 without setting time limits, using the terms ‘bladder cancer’ in conjunction with ‘cystoscopy’, ‘diagnosis’, ‘detection’, ‘fluorescence’, ‘blue-light’, ‘PDD’, ‘narrow band imaging’, ‘molecular imaging’, ‘optical coherence tomography’ or ‘confocal laser endomicroscopy’.

Results

The new imaging techniques can be classified according to their scope as macroscopic, microscopic, and molecular. Macroscopic techniques, such as narrow band imaging, are similar to white light cystoscopy; however, they help visualize even very minute lesions in the bladder mucosa by means of contrast enhancement.

Microscopic imaging techniques, such as optical coherence tomography and confocal laser endomicroscopy, provide high-resolution cross-sectional views of vesicular tissues, which resemble images obtained by histopathological examination. Therefore, these are referred as ‘optical biopsy’. Molecular imaging methods offer highly specific real-time visualization of cancer cells and their differentiation from healthy tissue, by combining optical imaging with fluorescent labeling of elements such as antibodies.

Conclusions

In this article we present a review of studies and literature concerning modern optical diagnostic techniques for non-muscle-invasive bladder cancer. We present available technology with its advantages and disadvantages, and studies regarding its effectiveness.

Role of Narrow Band Imaging in Management of Urothelial Carcinoma

Urothelial carcinoma of the bladder and upper tract is primarily diagnosed by white light endoscopy, which has well-known limitations that contribute to the increased risk of tumor recurrence and progression. Narrow band imaging (NBI) is an optical imaging technology that facilitates detection of tumor vasculature and differentiation of benign urothelium from neoplastic tissue. For urothelial carcinoma, NBI may be utilized in a variety of clinical settings, including office cystoscopy for initial identification and surveillance, transurethral resection for pathological diagnosis, and ureteroscopic management of upper tract lesions. Early evidence suggests that NBI increases the detection of urothelial carcinoma in the bladder and upper tract, including flat high-grade lesions such as carcinoma-in-situ that are a diagnostic challenge under white light. NBI also appears to improve the quality of transurethral resection and thereby reduce the frequency of tumor recurrence.

A Multimodal Imaging Approach for Longitudinal Evaluation of Bladder Tumor Development in an Orthotopic Murine Model

Bladder cancer is the fourth most common malignancy amongst men in Western industrialized countries with an initial response rate of 70% for the non-muscle invasive type, and improving therapy efficacy is highly needed. For this, an appropriate, reliable animal model is essential to gain insight into mechanisms of tumor growth for use in response monitoring of (new) agents. Several animal models have been described in previous studies, but so far success has been hampered due to the absence of imaging methods to follow tumor growth non-invasively over time. Recent developments of multimodal imaging methods for use in animal research have substantially strengthened these options of in vivo visualization of tumor growth. In the present study, a multimodal imaging approach was addressed to investigate bladder tumor proliferation longitudinally. The complementary abilities of Bioluminescence, High Resolution Ultrasound and Photo-acoustic Imaging permit a better understanding of bladder tumor development. Hybrid imaging modalities allow the integration of individual strengths to enable sensitive and improved quantification and understanding of tumor biology, and ultimately, can aid in the discovery and development of new therapeutics.

Hexaminolevulinate hydrochloride in the detection of nonmuscle invasive cancer of the bladder

Clinical trials have shown that hexaminolevulinate (HAL) fluorescence cystoscopy improves the detection of bladder tumors compared with standard white-light cystoscopy, resulting in more efficacious treatment. However, some recent meta-analyses report controversially on recurrence-free rates with this procedure. A systematic review of literature was performed from December 2014 to January 2015 using the PubMed, Embase and Cochrane databases for controlled trials on photodynamic diagnosis (PDD) with HAL. A total of 154 publications were found up to January 2015. Three of the authors separately reviewed the records to evaluate eligibility and methodological quality of clinical trials. A total of 16 publications were considered eligible for analysis. HAL-PDD-guided cystoscopy increased overall tumor detection rate (proportion difference 19%, 95% confidence interval [CI] 0.152-0.236) although the benefit was particularly significant in patients with carcinoma in situ (CIS) lesion (proportion difference 15.7%, 95% CI 0.069-0.245) and was reduced in papillary lesions (Ta proportion difference 5.9%, 95% CI 0.014-0.103 and T1 proportion difference 1.2%, 95% CI 0.033-0.057). Moreover, there were 15% of patients (95% CI 0.098-0.211) with at least one additional tumor seen with PDD. With regard to recurrence rates, the data sample was insufficient for a statistical analysis, although the evaluation of raw data showed a trend in favor of HAL-PDD. This meta-analysis confirms the increased tumor detection rate by HAL-PDD with a most pronounced benefit for CIS lesion.

Diagnostics techniques in nonmuscle invasive bladder cancer

INTRODUCTION

Nonmuscle invasive bladder cancer (NMIBC) is the most common presentation of bladder cancer and is often treatable with endoscopic resection and intravesical therapies. Cystoscopy and urine cytology are the gold standard in diagnosis and surveillance but are limited by their sensitivity in some situations. We seek to provide an overview of recent additions to the diagnostic armamentarium for urologists treating this disease.

METHODS

Articles were identified through a literature review of articles obtained through PubMed searches including the terms "bladder cancer" and various diagnostic techniques described in the article.

RESULTS

A variety of urinary biomarkers are available to assist the diagnosis and management of patients with NMIBC. Many have improved sensitivity over urine cytology, but less specificity. There are certain situations in which this has proved valuable, but as yet these are not part of the standard guidelines for NMIBC. Fluorescence cystoscopy has level 1 evidence demonstrating increased rates of tumor detection and prolonged recurrence-free survival when utilized for transurethral resection. Other technologies seeking to enhance cystoscopy, such as narrow band imaging, confocal laser endomicroscopy, and optical coherence tomography are still under evaluation.

CONCLUSIONS

A variety of urine biomarker and adjunctive endoscopic technologies have been developed to assist the management of NMIBC. While some, such as fluorescence cystoscopy, have demonstrated a definite benefit in this disease, others are still finding their place in the diagnosis and treatment of this disease. Future studies should shed light on how these can be incorporated to improve outcomes in NMIBC.

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.

Confocal laser endomicroscopy of bladder and upper tract urothelial carcinoma: a new era of optical diagnosis?

Urothelial carcinoma of the bladder and upper tract pose significant diagnostic and therapeutic challenges. White light endoscopy plays a central role in the management of urothelial carcinoma but has several well-recognized shortcomings. New optical imaging technologies may improve diagnostic accuracy, enhance local cancer control, and better stratify treatment options. Confocal laser endomicroscopy enables dynamic imaging of the cellular structures below the mucosal surface and holds promise in providing real time optical diagnosis and grading of urothelial carcinoma. A variety of imaging probes are available that are compatible with the full spectrum of cystoscopes and ureteroscopes. We review the underlying principles and technique of confocal laser endomicroscopy in the urinary tract, with emphasis on specific application towards urothelial carcinoma. While the available data are largely related to urothelial carcinoma of the bladder, the lessons learned are directly applicable to the upper tract, where the clinical needs are significant. Ongoing efforts to optimize this technology offer an exciting glimpse into future advances in optical imaging and intraoperative image guidance.

Decision Based on Narrow Band Imaging Cystoscopy without a Referential Normal Standard Rather Increases Unnecessary Biopsy in Detection of Recurrent Bladder Urothelial Carcinoma Early after Intravesical Instillation

Purpose

The purpose of this study was to calculate the operating characteristics of narrowband imaging (NBI) cystoscopy versus traditional white light cystoscopy (WLC) in common clinical scenarios involving suspicion of bladder urothelial carcinoma (UC).

Materials and Methods

Sixty-three consecutive patients initially underwent WLC and then NBI in a single session for evaluation of microscopic hematuria (group I, n=20), gross hematuria (group II, n=19), and follow-up for prior UC (group III, n=24), by an experienced urologist. All lesions that were abnormal in contrast with adjacent normal mucosa were diagnosed as positive and biopsied.

Results

Sixty-six biopsies from 47 patients were performed. Pathologic examination showed 17 cases of UC from 21 sites. While the overall sensitivity of NBI was similar to that of WLC (100% vs. 94.1%), the specificity of NBI was significantly lower than that of WLC (50% vs. 86.9%, p < 0.001), particularly in group III (38.9% vs. 88.9%, p=0.004). Based on identification by NBI only, 23 additional biopsies from 18 cases were performed for identification of one patient with UC, who belonged to group III. In this group, to identify this specific patient, 15 additional biopsies were performed from 10 patients. All seven cases with positive findings from NBI within 2 months after the last intravesical therapy were histologically proven as negative.

Conclusion

In evaluation for recurrence early after intravesical instillation, the decision based on NBI increased unnecessary biopsy in the absence of an established standard for judging NBI.

Advances in imaging technologies in the evaluation of high-grade bladder cancer

Bladder cancer ranges from a low-grade variant to high-grade disease. Assessment for treatment depends on white light cystoscopy, however because of its limitations there is a need for improved visualization of flat, multifocal, high-grade, and muscle-invasive lesions. Photodynamic diagnosis and narrow-band imaging provide additional contrast enhancement of bladder tumors and have been shown to improve detection rates. Confocal laser endomicroscopy and optical coherence tomography enable real-time, high-resolution, subsurface tissue characterization with spatial resolutions similar to histology. Molecular imaging offers the potential for the combination of optical imaging technologies with cancer-specific molecular agents to improve the specificity of disease detection.