Fluorescence detection of bladder cancer: a review

In vivo assessment of bladder cancer with diffuse reflectance and fluorescence spectroscopy: A comparative study

OBJECTIVES

The aim of this work is to assess the performance of multimodal spectroscopic approach combined with single core optical fiber for detection of bladder cancer during surgery in vivo.

METHODS

Multimodal approach combines diffuse reflectance spectroscopy (DRS), fluorescence spectroscopy in the visible (405 nm excitation) and near-infrared (NIR) (690 nm excitation) ranges, and high-wavenumber Raman spectroscopy. All four spectroscopic methods were combined in a single setup. For 21 patients with suspected bladder cancer or during control cystoscopy optical spectra of bladder cancer, healthy bladder wall tissue and/or scars were measured. Classification of cancerous and healthy bladder tissue was performed using machine learning methods.

RESULTS

Statistically significant differences in relative total haemoglobin content, oxygenation, scattering, and visible fluorescence intensity were found between tumor and normal tissues. The combination of DRS and visible fluorescence spectroscopy allowed detecting cancerous tissue with sensitivity and specificity of 78% and 91%, respectively. The addition of features extracted from NIR fluorescence and Raman spectra did not improve the quality of classification.

CONCLUSIONS

This study demonstrates that multimodal spectroscopic approach allows increasing sensitivity and specificity of bladder cancer detection in vivo. The developed approach does not require special probes and can be used with single-core optical fibers applied for laser surgery.

A step ahead to enhancing routine breast cancer resection: Spheroid and hen's egg chorioallantoic membrane models to assess the photodynamic diagnosis efficiency of ALA and PSI-ALA-hex

Aminolevulinic acid (ALA) and its derivatives have been used in the diagnosis of several diseases through topical, intravesical, and oral administration. However, their intravenous use for the theranostics of cancers has not raised interest despite its potential advantages. In this study, we compared the efficacy of ALA, its hexyl ester ALA-Hex, and our new derivative PSI-ALA-Hex to induce a fluorescent protoporphyrin IX (PpIX) overproduction in breast cancers. First, we tested the drugs on four subtypes of breast cancer spheroids in vitro. Our results demonstrated the capacity of ALA-Hex and PSI-ALA-Hex to produce PpIX in all breast spheroids, although ALA struggled in half of the models. We applied the chick embryo in vivo model to investigate the intravenous administration route of ALA and PSI-ALA-Hex, ALA-Hex being toxic. We engrafted breast cancer nodules having various hormonal profiles onto the chorioallantoic membrane of the eggs. They were all detected by fluorescence imaging with mild efficacy using PSI-ALA-Hex, which displayed a maximum selectivity of 2.2 to 2.9, whereas ALA showed a higher selectivity from 3.2 to 5.1 at 300 μmol/kg. PSI-ALA-Hex was less appropriate for the diagnosis of breast cancer by intravenous administration. We show for the first time, to the best of our knowledge, the photodetection and imaging of a wide range of breast tumors in vivo upon intravenous treatment with ALA.

Recent microfluidic advances in submicron to nanoparticle manipulation and separation

Manipulation and separation of submicron and nanoparticles are indispensable in many chemical, biological, medical, and environmental applications. Conventional technologies such as ultracentrifugation, ultrafiltration, size exclusion chromatography, precipitation and immunoaffinity capture are limited by high cost, low resolution, low purity or the risk of damage to biological particles. Microfluidics can accurately control fluid flow in channels with dimensions of tens of micrometres. Rapid microfluidics advancement has enabled precise sorting and isolating of nanoparticles with better resolution and efficiency than conventional technologies. This paper comprehensively studies the latest progress in microfluidic technology for submicron and nanoparticle manipulation. We first summarise the principles of the traditional techniques for manipulating nanoparticles. Following the classification of microfluidic techniques as active, passive, and hybrid approaches, we elaborate on the physics, device design, working mechanism and applications of each technique. We also compare the merits and demerits of different microfluidic techniques and benchmark them with conventional technologies. Concurrently, we summarise seven standard post-separation detection techniques for nanoparticles. Finally, we discuss current challenges and future perspectives on microfluidic technology for nanoparticle manipulation and separation.

A Recap of Heme Metabolism towards Understanding Protoporphyrin IX Selectivity in Cancer Cells

Mitochondria are essential organelles of mammalian cells, often emphasized for their function in energy production, iron metabolism and apoptosis as well as heme synthesis. The heme is an iron-loaded porphyrin behaving as a prosthetic group by its interactions with a wide variety of proteins. These complexes are termed hemoproteins and are usually vital to the whole cell comportment, such as the proteins hemoglobin, myoglobin or cytochromes, but also enzymes such as catalase and peroxidases. The building block of porphyrins is the 5-aminolevulinic acid, whose exogenous administration is able to stimulate the entire heme biosynthesis route. In neoplastic cells, this methodology repeatedly demonstrated an accumulation of the ultimate heme precursor, the fluorescent protoporphyrin IX photosensitizer, rather than in healthy tissues. While manifold players have been proposed, numerous discrepancies between research studies still dispute the mechanisms underlying this selective phenomenon that yet requires intensive investigations. In particular, we wonder what are the respective involvements of enzymes and transporters in protoporphyrin IX accretion. Is this mainly due to a boost in protoporphyrin IX anabolism along with a drop of its catabolism, or are its transporters deregulated? Additionally, can we truly expect to find a universal model to explain this selectivity? In this report, we aim to provide our peers with an overview of the currently known mitochondrial heme metabolism and approaches that could explain, at least partly, the mechanism of protoporphyrin IX selectivity towards cancer cells.

Consensus Conference Statement on the General Use of Near-infrared Fluorescence Imaging and Indocyanine Green Guided Surgery: Results of a Modified Delphi Study

BACKGROUND

In recent decades, the use of near-infrared light and fluorescence-guidance during open and laparoscopic surgery has exponentially expanded across various clinical settings. However, tremendous variability exists in how it is performed.

OBJECTIVE

In this first published survey of international experts on fluorescence-guided surgery, we sought to identify areas of consensus and nonconsensus across 4 areas of practice: fundamentals; patient selection/preparation; technical aspects; and effectiveness and safety.

METHODS

A Delphi survey was conducted among 19 international experts in fluorescence-guided surgery attending a 1-day consensus meeting in Frankfurt, Germany on September 8th, 2019. Using mobile phones, experts were asked to anonymously vote over 2 rounds of voting, with 70% and 80% set as a priori thresholds for consensus and vote robustness, respectively.

RESULTS

Experts from 5 continents reached consensus on 41 of 44 statements, including strong consensus that near-infrared fluorescence-guided surgery is both effective and safe across a broad variety of clinical settings, including the localization of critical anatomical structures like vessels, detection of tumors and sentinel nodes, assessment of tissue perfusion and anastomotic leaks, delineation of segmented organs, and localization of parathyroid glands. Although the minimum and maximum safe effective dose of ICG were felt to be 1 to 2 mg and >10 mg, respectively, there was strong consensus that determining the optimum dose, concentration, route and timing of ICG administration should be an ongoing research focus.

CONCLUSIONS

Although fluorescence imaging was almost unanimously perceived to be both effective and safe across a broad range of clinical settings, considerable further research remains necessary to optimize its use.

Raman spectroscopy biochemical characterisation of bladder cancer cisplatin resistance regulated by FDFT1: a review

Bladder cancer is the fourth most common malignancy in males. It can present across the whole continuum of severity, from mild through well-differentiated disease to extremely malignant tumours with poor survival rates. As with other vital organ malignancies, proper clinical management involves accurate diagnosis and staging. Chemotherapy consisting of a cisplatin-based regimen is the mainstay in the management of muscle-invasive bladder cancers. Control via cisplatin-based chemotherapy is threatened by the development of chemoresistance. Intracellular cholesterol biosynthesis in bladder cancer cells is considered a contributory factor in determining the chemotherapy response. Farnesyl-diphosphate farnesyltransferase 1 (FDFT1), one of the main regulatory components in cholesterol biosynthesis, may play a role in determining sensitivity towards chemotherapy compounds in bladder cancer. FDFT1-associated molecular identification might serve as an alternative or appendage strategy for early prediction of potentially chemoresistant muscle-invasive bladder cancer tissues. This can be accomplished using Raman spectroscopy. Developments in the instrumentation have led to it becoming one of the most convenient forms of analysis, and there is a highly realistic chance that it will become an effective tool in the pathology lab. Chemosensitive bladder cancer tissues tend to have a higher lipid content, more protein genes and more cholesterol metabolites. These are believed to be associated with resistance towards bladder cancer chemotherapy. Herein, Raman peak assignments have been tabulated as an aid to indicating metabolic changes in bladder cancer tissues that are potentially correlated with FDFT1 expression.

Time to Turn on the Blue Lights: A Systematic Review and Meta-analysis of Photodynamic Diagnosis for Bladder Cancer

Context

White light (WL) cystoscopy and transurethral resection of bladder tumour (TURBT) comprise the current gold standard technique for detecting and grading bladder cancer. However, with WL cystoscopy, recurrence following initial TURBT is high, and identification of smaller tumours and carcinoma in situ is poor. Photodynamic diagnosis (PDD) has been developed to improve the detection of bladder.

Objective

To assess the effect of PDD-guided TURBT compared with WL on recurrence rates (RRs) in non-muscle-invasive bladder cancer (NMIBC).

Evidence acquisition

A systematic review of the literature from inception to April 2020 using Medline, EMBASE, and CENTRAL was undertaken. Randomised control trials comparing TURBT undertaken with PDD to WL that reported RRs of at least 12 mo were included in the analysis. The primary outcomes were RRs at 12 and 24 mo. The secondary outcomes were reported adverse effects. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology was used to assess the certainty of the evidence.

Evidence synthesis

Twelve randomised controlled trials (2288 patients) were included for the meta-analysis. PDD was found to reduce RRs at 12 mo (RR 0.73, confidence interval [CI] 0.60-0.88) and 24 mo (RR 0.75, CI 0.62-0.91). There was an increased risk of recurrence for patients undergoing WL at 12 mo (hazard ratio [HR] 1.14, CI 1.05-1.23) and 24 mo (HR 1.25, CI 1.15-1.35). Two studies reported recurrence data at 60 mo showing statistically significant outcomes in favour of PDD: one showed lower RRs for PDD (49% PDD vs 68% WL), whilst the other showed increased recurrence-free survival (68.2% PDD vs 57.3% WL). Adverse effects appeared to be minimal, though poorly reported. A GRADE analysis showed the evidence to be of moderate certainty overall.

Conclusions

This systematic review found that PDD reduced RRs and improved recurrence-free survival compared with WL in NMIBC over at least 2-yr follow-up. These effects may persist up to 5 yr. Further research in a pragmatic study looking at longer-term outcomes beyond 24 mo will help guide recommendations on clinical adoption.

Patient summary

This review suggests that photodynamic diagnosis, compared with white light cystoscopy, improves recurrence-free survival in non-muscle-invasive bladder cancer over at least 2 yr of follow-up. However, confirmatory pragmatic studies with longer-term outcomes are required for its clinical adoption.

Nerve spectroscopy: understanding peripheral nerve autofluorescence through photodynamics

BACKGROUND

Being able to accurately identify sensory and motor nerves is crucial during surgical procedures to prevent nerve injury. We aimed to (1) evaluate the feasibility of performing peripheral human nerve visualization utilizing nerves' own autofluorescence in an ex-vivo model; (2) compare the effect of three different nerve fiber fixation methods on the intensity of fluorescence, indicated as the intensity ratio; and (3) similarly compare three different excitation ranges.

METHODS

Samples from various human peripheral nerves were selected postoperatively. Nerve fibers were divided into three groups: Group A nerve fibers were washed with a physiologic solution; Group B nerve fibers were fixated with formaldehyde for 6 h first, and then washed with a physiologic solution; Group C nerve fibers were fixated with formaldehyde for six hours, but not washed afterwards. An Olympus IX83 inverted microscope was used for close-up image evaluation. Nerve fibers were exposed to white-light wavelength spectrums for a specific time frame prior to visualization under three different filters-Filter 1-LF405-B-OMF Semrock; Filter 2-U-MGFP; Filter 3-U-MRFPHQ Olympus, with excitation ranges of 390-440, 460-480, and 535-555, respectively. The fluorescence intensity of all images was subsequently analyzed using Image-J Software, and results compared by analysis of variance (ANOVA).

RESULTS

The intensity ratios observed with Filter 1 failed to distinguish the different nerve fiber groups (p = 0.39). Conversely, the intensity ratios seen under Filters 2 and 3 varied significantly between the three nerve-fiber groups (p = 0.021, p = 0.030, respectively). The overall intensity of measurements was greater with Filter 1 than Filter 3 (p < 0.05); however, all nerves were well visualized by all filters.

CONCLUSION

The current results on ex vivo peripheral nerve fiber autofluorescence suggest that peripheral nerve fiber autofluorescence intensity does not greatly depend upon the excitation wavelength or fixation methods used in an ex vivo setting. Implications for future nerve-sparing surgery are discussed.

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.

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.

Biosensor device for the photo-specific detection of immuno-captured bladder cancer cells using hexaminolevulinate: An ex-vivo study

Exogenous administration of the photodynamic agent hexaminolevulinate induces Protoporphyrin IX (PpIX) accumulation in malignant tissue. This may enable differentiation from healthy tissues by emission of a distinctive red fluorescence. It provides the photo-specific detection when excited with blue light at 405 nm. This study determines the ex-vivo processing conditions (time, concentration, temperature and addition of a fluorescent dye) required for HAL-induced PpIX fluorescence to successfully discriminate between bladder cancer and benign fibroblast cells shed in urine at the single cell level. HAL-induced fluorescence was 4.5 times brighter in cancer cells than non-cancer cells when incubated in the optimum conditions, and could be used to correctly identified bladder cancer cells captured within a newly developed immunofunctionalized biosensor with 88% efficiency. This biosensor is designed to facilitate the immuno-capture of cancer cells by interaction with carcinoma specific anti Epithelial Cell Adhesion molecule (anti-EpCAM) antibodies. Anti-EpCAM antibodies were immobilized on polyoxazoline (POx) plasma polymers by covalent bonds in microfluidic channels. Combining photodynamic and immunoselective approach therefore constitute a promising approach for the non-invasive diagnosis of bladder cancer with two independent level of confidence.

OBJECTIVE

This study investigate the relationship between different regulatory factors (time, concentration, temperature and addition of a fluorescent dye) and Hexaminolevulinate (HAL)-mediated photodynamic diagnosis of bladder cancer (PDD) in vitro. We examine the natural photosensitizer Protoporphyrin IX (PpIX) fluorescence induced by HAL in several human bladder cancer cell lines and one non-cancer foreskin fibroblast cell line and identify the processing conditions that maximise the difference in fluorescence intensity between malign and benign cell types. The detection of HAL induced fluorescence at a single cell level by a selective cancer cell capture platform is also tested.

MATERIALS AND METHODS

Experiments were performed on cultured monolayer cells and cells in suspension. The cell lines examined included the transitional epithelium carcinoma cell lines HT1197, HT1376, EJ138 and RT4, and the non-cancer foreskin fibroblasts HFF. Cells were incubated with HAL in various doses, time and temperature settings. We also used the nuclear red as a tool to study the PpIX subcellular localization. PpIX fluorescence intensities were measured and analysed using fluorescence microscope software. Finally, we evaluated the possibility of using HAL to discriminate between cancer and non-cancer cells from a mixed cell population using a newly developed immunofunctionalized microfluidic platform.

RESULTS

The accumulation of PpIX in bladder cancer cells was significantly higher than in non-cancer cells, both cultured monolayer cells and cells in suspension. Effectively, the fluorescence intensity was 4.5 times brighter in bladder cancer cells than non-cancer foreskin fibroblast cells when incubated in the optimum condition, in which the nuclear stain adjuvant acted as a fluorescence enhancer. Cancer cells displayed PpIX accumulated mainly in mitochondria but none or very little PpIX was observed in non-cancer cells. HAL-induced fluorescence could be used to correctly identify bladder cancer cells within the EpCAM conjugated POx based microfluidic sensor with an 88% capture selectivity rate.

CONCLUSIONS

These findings prove that the application of HAL-induced PpIX fluorescence can successfully distinguish between cancer and non-cancer cells in vitro. This test can provide advanced second level of confidence on the cancerous nature of cells captured by the immunofunctionalized bladder cancer diagnostic platform.

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.

Efficacy of 5-Aminolevulinic Acid in Photodynamic Detection and Photodynamic Therapy in Veterinary Medicine

5-Aminolevulinic acid (5-ALA), a commonly used photosensitizer in photodynamic detection (PDD) and therapy (PDT), is converted in situ to the established photosensitizer protoporphyrin IX (PpIX) via the heme biosynthetic pathway. To extend 5-ALA-PDT application, we evaluated the PpIX fluorescence induced by exogenous 5-ALA in various veterinary tumors and treated canine and feline tumors. 5-ALA-PDD sensitivity and specificity in the whole sample group for dogs and cats combined were 89.5 and 50%, respectively. Notably, some small tumors disappeared upon 5-ALA-PDT. Although single PDT application was not curative, repeated PDT+/−chemotherapy achieved long-term tumor control. We analyzed the relationship between intracellular PpIX concentration and 5-ALA-PDT in vitro cytotoxicity using various primary tumor cells and determined the correlation between intracellular PpIX concentration and 5-ALA transporter and metabolic enzyme mRNA expression levels. 5-ALA-PDT cytotoxicity in vitro correlated with intracellular PpIX concentration in carcinomas. Ferrochelatase mRNA expression levels strongly negatively correlated with PpIX accumulation, representing the first report of a correlation between mRNA expression related to PpIX accumulation and PpIX concentration in canine tumor cells. Our findings suggested that the results of 5-ALA-PDD might be predictive for 5-ALA-PDT therapeutic effects for carcinomas, with 5-ALA-PDT plus chemotherapy potentially increasing the probability of tumor control in veterinary medicine.

Hypericin-functionalized graphene oxide for enhanced mitochondria-targeting and synergistic anticancer effect

Effective targeting of mitochondria has emerged as a beneficial strategy in cancer therapy. However, the development of mitochondria-targeting ligands is difficult because of the low permeability of the mitochondrial double membrane. We found that hypericin (HY), a natural product isolated from Hypericum perforatum L., is an effective mitochondria-targeting ligand. HY-functionalized graphene oxide (GO) loaded with doxorubicin (GO-PEG-SS-HY/DOX) increased the synergistic anticancer efficacy of phototherapy and chemotherapy in the absence of apparent adverse side effects. In vitro and in vivo assays suggested GO-PEG-SS-HY/DOX induced the expression of the key proteins of the mitochondria-mediated apoptosis pathway and caused apoptosis of breast carcinoma cells. In addition, GO vehicle exhibited low toxicity toward normal cells, indicating high safety of functionalized GO preparations in antitumor therapy. Therefore, HY-functionalized GO can be successfully used as a platform technology to target mitochondria in cancer cells and improve the therapeutic efficacy of chemotherapeutic drugs.

STATEMENT OF SIGNIFICANCE

Induction of mitochondria-mediated apoptosis is a promising approach in cancer therapy. However, mitochondria are difficult to access and permeate because of their negative membrane potential and highly dense double membrane. Mitochondria-targeting ligands can be conjugated to nanoparticles or small-molecule drugs to enhance their antitumor effect. Here, we showed that the natural photosensitizer hypericin is a novel mitochondria-targeting ligand and that graphene oxide particles co-loaded with hypericin and the chemotherapeutic agent doxorubicin exhibited a synergistic antitumor effect mediated by the mitochondrial-mediated apoptosis. Treatment with such particles in combination with laser irradiation led to apoptosis of the tumor MDA-MB-231 and MCF-7 cells in vitro and in vivo. Furthermore, treatment with hypericin/doxorubicin-functionalized graphene oxide had low cellular toxicity.

Optical redox ratio and endogenous porphyrins in the detection of urinary bladder cancer: A patient biopsy analysis

Bladder cancer is among the most common cancers in the UK and conventional detection techniques suffer from low sensitivity, low specificity, or both. Recent attempts to address the disparity have led to progress in the field of autofluorescence as a means to diagnose the disease with high efficiency, however there is still a lot not known about autofluorescence profiles in the disease. The multi-functional diagnostic system "LAKK-M" was used to assess autofluorescence profiles of healthy and cancerous bladder tissue to identify novel biomarkers of the disease. Statistically significant differences were observed in the optical redox ratio (a measure of tissue metabolic activity), the amplitude of endogenous porphyrins and the NADH/porphyrin ratio between tissue types. These findings could advance understanding of bladder cancer and aid in the development of new techniques for detection and surveillance.

Laser-induced autofluorescence spectroscopy: can it be of importance in detection of bladder lesions?

BACKGROUND

Non-muscle invasive bladder cancer can be missed during white light endoscopy in up to 50% of cases. We aimed to test whether or not we could find a difference between benign and cancerous tissue wavelengths using laser induced autofluorescence spectroscopy can increase cancer detection.

MATERIALS AND METHODS

We analysed 67 tissue samples using spectral analysis. The WavSTAT (Spectra Science) optical biopsy device was used to record fluorescence spectra from biopsied tissue enabling calculation of an AUC for each spectrum, a measure of the mean spectral wavelength (λ¯ (nm)) and a dimensionless fluorescence ratio. Mann-Whitney test was used to compare the two groups.

RESULTS

We found that 49.3% (33/67) of the tissue was benign, 44.8% (30/67) was CIS/cancerous tissue, and the remaining 4/67 samples were atypia (2) and dysplasia (2). The median AUC for the benign tissue was 19.53 (interquartile range [IQR]: 5.35-30.39) and that for CIS/cancerous tissue was 7.05 (IQR: 2.89-14.24) (P=0.002). The median wavelengths for the benign tissue and malignant tissue were 502.4nm (IQR: 500.3-504.3nm) and 505.2nm (IQR: 502.1-513.2nm), respectively (P=0.003). The median fluorescence ratio was 0.080 (IQR: 0.070-0.088) for benign tissue and 0.096 (IQR: 0.079-0.221) for CIS/cancerous tissue (P=0.002).

CONCLUSIONS

We found statistical differences between the median AUC calculations and median wavelengths for the benign and cancerous tissue. We also found a statistical difference between the fluorescence ratios between the two tissue types. There seems to be a role for optical spectroscopy in verifying bladder lesions.

Laser polarization autofluorescence of endogenous porphyrins of optically anisotropic biological tissues and fluids in diagnostics of necrotic and pathological changes of human organs

This research presents the results of investigation of laser polarization fluorescence of biological layers (histological sections, cytological smears). The polarization structural properties of autofluorescent images of human biological tissues layers and fluids were found and investigated. A model describing the formation of polarizationally heterogeneous images of optically anisotropic biological layers is suggested. On this basis, the practical method of polarization-variable autofluorescence is analytically substantiated and experimentally tested. The efficiency of applying this method to various tasks of medical diagnostics is analyzed: objectification of histological conclusions, defining and differentiating of various forms of cancer (dysplasia--microinvasive cancer) of the cervix uteri, and forensic medical express-differentiation of cause of death. The objective criteria (statistical moments) of differentiation of autofluorescent images of histological sections of myocardium biopsy and endometrium and cytological smears of its mucous tunic are defined. The operational characteristics (sensitivity, specificity, accuracy) of this method are determined concerning the positions of probative medicine, and the clinical efficiency of the technique is demonstrated.

Design and characterization of an optimized simultaneous color and near-infrared fluorescence rigid endoscopic imaging system

We report the design, characterization, and validation of an optimized simultaneous color and near-infrared (NIR) fluorescence rigid endoscopic imaging system for minimally invasive surgery. This system is optimized for illumination and collection of NIR wavelengths allowing the simultaneous acquisition of both color and NIR fluorescence at frame rates higher than 6.8 fps with high sensitivity. The system employs a custom 10-mm diameter rigid endoscope optimized for NIR transmission. A dual-channel light source compatible with the constraints of an endoscope was built and includes a plasma source for white light illumination and NIR laser diodes for fluorescence excitation. A prism-based 2-CCD camera was customized for simultaneous color and NIR detection with a highly efficient filtration scheme for fluorescence imaging of both 700- and 800-nm emission dyes. The performance characterization studies indicate that the endoscope can efficiently detect fluorescence signal from both indocyanine green and methylene blue in dimethyl sulfoxide at the concentrations of 100 to 185 nM depending on the background optical properties. Finally, we performed the validation of this imaging system in vivo during a minimally invasive procedure for thoracic sentinel lymph node mapping in a porcine model.

Tumor cell differentiation by label-free fluorescence microscopy

Autofluorescence spectra, images, and decay kinetics of U251-MG glioblastoma cells prior and subsequent to activation of tumor suppressor genes are compared. While phase contrast images and fluorescence intensity patterns of tumor (control) cells and less malignant cells are similar, differences can be deduced from autofluorescence spectra and decay kinetics. In particular, upon near UV excitation, the fluorescence ratio of the free and protein-bound coenzyme nicotinamid adenine dinucleotide depends on the state of malignancy and reflects different cytoplasmic (including lysosomal) and mitochondrial contributions. While larger numbers of fluorescence spectra are evaluated by principal component analysis, a multivariate data analysis method, additional information on cell metabolism is obtained from spectral imaging and fluorescence lifetime imaging microscopy.

Toward real-time virtual biopsy of oral lesions using confocal laser endomicroscopy interfaced with embedded computing

Oral lesions are conventionally diagnosed using white light endoscopy and histopathology. This can pose a challenge because the lesions may be difficult to visualise under white light illumination. Confocal laser endomicroscopy can be used for confocal fluorescence imaging of surface and subsurface cellular and tissue structures. To move toward real-time "virtual" biopsy of oral lesions, we interfaced an embedded computing system to a confocal laser endomicroscope to achieve a prototype three-dimensional (3-D) fluorescence imaging system. A field-programmable gated array computing platform was programmed to enable synchronization of cross-sectional image grabbing and Z-depth scanning, automate the acquisition of confocal image stacks and perform volume rendering. Fluorescence imaging of the human and murine oral cavities was carried out using the fluorescent dyes fluorescein sodium and hypericin. Volume rendering of cellular and tissue structures from the oral cavity demonstrate the potential of the system for 3-D fluorescence visualization of the oral cavity in real-time. We aim toward achieving a real-time virtual biopsy technique that can complement current diagnostic techniques and aid in targeted biopsy for better clinical outcomes.

New frontier in hypericin-mediated diagnosis of cancer with current optical technologies

Photosensitizers (PSs) have shown great potentials as molecular contrast agents in photodynamic diagnosis (PDD) of cancer. While the diagnostic values of PSs have been proven previously, little efforts have been put into developing optical imaging and diagnostic algorithms. In this article, we review the recent development of optical probes that have been used in conjunction with a potent PS, hypericin (HY). Various fluorescence techniques such as laser confocal microscopy, fluorescence urine cytology, endoscopy and endomicroscopy are covered. We will also discuss about image processing and classification approaches employed for accurate PDD. We anticipate that continual efforts in these developments could lead to an objective PDD and complete surgical clearance of tumors. Recent advancements in nanotechnology have also opened new horizons for PSs. The use of biocompatible gold nanoparticles as carrier for enhanced targeted delivery of HY has been attained. In addition, plasmonic properties of nanoparticles were harnessed to induce localized hyperthermia and to manage the release of PS molecules, enabling a better therapeutic outcome of a combined photodynamic and photothermal therapy. Finally, we discuss how nanoparticles can be used as contrast agents for other optical techniques such as optical coherence tomography and surface-enhanced Raman scattering imaging.

Advances in bio-optical imaging for the diagnosis of early oral cancer

Oral cancer is among the most common malignancies worldwide, therefore early detection and treatment is imperative. The 5-year survival rate has remained at a dismal 50% for the past several decades. The main reason for the poor survival rate is the fact that most of the oral cancers, despite the general accessibility of the oral cavity, are not diagnosed until the advanced stage. Early detection of the oral tumors and its precursor lesions may be the most effective means to improve clinical outcome and cure most patients. One of the emerging technologies is the use of non-invasive in vivo tissue imaging to capture the molecular changes at high-resolution to improve the detection capability of early stage disease. This review will discuss the use of optical probes and highlight the role of optical imaging such as autofluorescence, fluorescence diagnosis (FD), laser confocal endomicroscopy (LCE), surface enhanced Raman spectroscopy (SERS), optical coherence tomography (OCT) and confocal reflectance microscopy (CRM) in early oral cancer detection. FD is a promising method to differentiate cancerous lesions from benign, thus helping in the determination of adequate resolution of surgical resection margin. LCE offers in vivo cellular imaging of tissue structures from surface to subsurface layers and has demonstrated the potential to be used as a minimally invasive optical biopsy technique for early diagnosis of oral cancer lesions. SERS was able to differentiate between normal and oral cancer patients based on the spectra acquired from saliva of patients. OCT has been used to visualize the detailed histological features of the oral lesions with an imaging depth down to 2–3 mm. CRM is an optical tool to noninvasively image tissue with near histological resolution. These comprehensive diagnostic modalities can also be used to define surgical margin and to provide a direct assessment of the therapeutic effectiveness.

[Clinical experience with transurethral resection of bladder tumor (TUR-Bt) guided by photodynamic diagnosis (PDD)]

PURPOSE

To report our clinical experience regarding transurethral resection of bladder tumor (TUR-Bt) guided by photodynamic diagnosis (PDD) with intravesical instillations of 5-aminolevulinic acid (ALA) and to assess the usefulness of the therapeutic method.

MATERIALS AND METHODS

TUR-Bt guided by PDD was performed in 57 patients of which 47 were men and 10 women with a median age of 74.3 years (range 45-90), 36 were primary cases and 21 were recurrent cases with non-muscle invasive bladder cancer. Two to two and half hours prior to endoscopy 1.5 g ALA dissolved in 50 ml of 8.4% sodium hydrogen carbonate (NaHCO3) solution was instilled intravesically. For fluorescence excitation a blue light source (D-LIGHT System, Karl Storz Endoscopy Japan K.K.) was used. The tumorous lesions under white light guidance and the lesion with fluorescent excitation under blue (fluorescence) light guidance were taken by cold cup as a biopsy and also resected sequentially. To evaluate the accuracy of PDD, the levels in images of the ALA-induced fluorescence were compared with the pathological results. To evaluate the availability of TUR-Bt guided by PDD, survival Analysis regarding vesical recurrence was retrospectively examined compared to the cases underwent conventional TUR-Bt under white light guidance. Moreover, in these cases, multivariate analysis using Cox proportional-hazards model was performed to detect the clinico-pathological factor independently contribute to improving prognosis. (Results) In the 301 specimens obtained from 57 patients, the sensitivity and specificity of PDD were 92.5% and 60.1%, whereas the sensitivity and specificity of conventional endoscopic examination under white light guidance were 81.6% and 79.5%, respectively. Median follow-up period was 19.1 (range 8.6-49.9) months in 57 patients underwent TUR-Bt guided by PDD. Eight of 57 patients recurred and recurrence-free survival rate was 88.2 +/- 0.1% (at 12 months) and 76.2 +/- 0.1% (24-48 months). Median follow-up period was 49.9 (5.0-145.0) months in 149 patients underwent conventional TUR-Bt. Ninety-nine of 149 patients recurred and recurrence-free survival rate was 60.3 +/- 0.0% (12 months) and 31.6 +/- 0.0% (24-48 months). There was statistical significance in recurrence-free survival rate between these 2 therapeutic groups (p < 0.001). Moreover, multivariate analysis revealed the independent factor contribute to improving prognosis was only TUR-Bt guided by PDD (hazard ratio 0.279, p = 0.001).

CONCLUSION

It was suggested that TUR-Bt guided by PDD might reduce the risk of vesical recurrence in the early stage after operation of non-muscle invasive bladder cancer.

Incidental detection of an occult oral malignancy with autofluorescence imaging: a case report

Background

Autofluorescence imaging is used widely for diagnostic evaluation of various epithelial malignancies. Cancerous lesions display loss of autofluorescence due to malignant changes in epithelium and subepithelial stroma. Carcinoma of unknown primary site presents with lymph node or distant metastasis, for which the site of primary tumour is not detectable. We describe here the use of autofluorescence imaging for detecting a clinically innocuous appearing occult malignancy of the palate which upon pathological examination was consistent with a metastatic squamous cell carcinoma.

Case Description

A submucosal nodule was noted on the right posterior hard palate of a 59-year-old white female during clinical examination. Examination of this lesion using a multispectral oral cancer screening device revealed loss of autofluorescence at 405 nm illumination. An excisional biopsy of this nodule, confirmed the presence of a metastatic squamous cell carcinoma. Four years ago, this patient was diagnosed with metastatic squamous cell carcinoma of the right mid-jugular lymph node of unknown primary. She was treated with external beam irradiation and remained disease free until current presentation.

Conclusion

This case illustrates the important role played by autofluorescence tissue imaging in diagnosing a metastatic palatal tumour that appeared clinically innocuous and otherwise would not have been biopsied.

Clinical application of fluorescence endoscopic imaging using hypericin for the diagnosis of human oral cavity lesions

Background:

Diagnosis of oral cancer is conventionally carried out using white light endoscopy and histopathology of biopsy samples. However, oral tumours are mostly superficial and the lesion and its margins can be difficult to visualise under white light. We present clinical data on fluorescence diagnostic imaging of oral lesions using hypericin, a plant-based photosensitiser.

Methods:

Fluorescence images of lesions and normal tissue were captured using an endoscope after hypericin administration. The images were analysed to extract their colour parameters, which, along with the red-to-blue intensity ratios, were analysed and used to discriminate between tissue types. The results were correlated with those from histopathology.

Results:

The red-to-blue intensity ratio increased from normal to hyperplastic to cancerous tissue and was a good parameter to discriminate between these tissue types, with sensitivity and specificity levels of 90% and above.

Conclusion:

Our results show that hypericin fluorescence imaging has the potential to be used for the clinical diagnosis of oral cancer. Further study to enhance the clinical potential of this technique includes the development of a real-time image processing and analysis system interfaced to the endoscope to enable same-day cancer diagnosis and demarcation of lesion margins in a clinical setting.

Fluorescence cystoscopy with high-resolution optical coherence tomography imaging as an adjunct reduces false-positive findings in the diagnosis of urothelial carcinoma of the bladder

BACKGROUND

The advantage of photodynamic diagnosis in detecting urothelial cell carcinoma (UCC) of the bladder has been demonstrated clearly, but it comes at the price of a higher false-positive rate. Optical coherence tomography (OCT) is a noninvasive, real-time, microstructural imaging modality that uses near-infrared light for a point analysis of the bladder-wall microstructure.

OBJECTIVE

To evaluate whether adding targeted OCT analysis of lesions that are suspicious at white-light (WL) and hexaminolevulinate (HAL) fluorescence cystoscopy improves diagnostic accuracy in the detection of UCC.

DESIGN, SETTING, AND PARTICIPANTS

In this prospective single-center study with same-patient comparison, patients with suspected UCC first received an intravesical instillation of HAL. Cystoscopy was performed in WL, followed by blue-light inspection and OCT scanning.

INTERVENTION

Suspicious lesions identified by WL or HAL were evaluated by OCT and were subsequently resected or biopsied.

MEASUREMENTS

We measured changes in sensitivity and specificity in detecting UCC using WL, HAL, and targeted OCT.

RESULTS AND LIMITATIONS

In 66 patients studied, 232 lesions were detected, were scanned by OCT, and were subsequently resected or biopsied. Additionally, 132 areas of normal-appearing urothelium were investigated by all three methods and biopsied. On a per-lesion basis, sensitivity and specificity were respectively 69.3% and 83.7% for WL, 97.5% and 78.6% for HAL, and 97.5% and 97.9% for HAL combined with OCT. Overall, UCC was diagnosed in 58 patients (87.9%), with a per-patient sensitivity of 89.7% for WL and 100% for both HAL alone and HAL with targeted OCT. Per-patient specificity for HAL alone and targeted HAL was 62.5% and 87.5%, respectively. The limitation of OCT results from poor visualization of flat lesions in WL, making scanning a time-consuming procedure.

CONCLUSIONS

Combining fluorescence cystoscopy with targeted OCT increases the specificity of fluorescence cystoscopy significantly, with no added morbidity, and reduces the need for unnecessary (false-positive) biopsies.

Economic aspects of bladder cancer: what are the benefits and costs?

OBJECTIVE

Bladder cancer (BC) has the highest lifetime treatment costs per patient of all cancers. The high recurrence rate and ongoing invasive monitoring requirement are the key contributors to the economic and human toll of this disease. The purpose of this paper was to utilize the recent literature to identify opportunities for improving the benefits and costs of BC care.

METHODS

A PubMed search was performed of recent publications concerning (BC) cost-effectiveness. We reviewed studies, reviews, opinion papers and cost-effectiveness analyses, focusing primarily on non-muscle-invasive bladder cancer (Ta/T1; NMIBC).

RESULTS

New diagnostic tools such as urine markers may assist in more cost-effectively detecting BC at an earlier stage, however, these markers cannot replace the cystoscopy, which is the current standard of care. A photodynamic diagnostic tool (PDD) using hexylaminolevulinate (Hexvix) enhances tumor visibility and improves transurethral resection of bladder cancer (TURB) results, potentially reducing recurrence rates and lowering treatment costs. While the importance of BC research has been acknowledged, research investment has been continuously reduced during the last 5 years.

CONCLUSIONS

The economic burden of BC is well-characterized in the literature. This study suggests that new technologies (i.e., urine-based tests, PDD) and therapeutic regimes (intravesical chemotherapy, adjuvant immunotherapy) have significant potential to improve the diagnosis, treatment and on-going monitoring of BC patients, with potential improvements in clinical outcomes and concurrent cost-savings. A renewed interest and investment in BC research are required to ensure future advancements.

Screening of nanoparticulate delivery systems for the photodetection of cancer in a simple and cost-effective model

AIMS

In urology, fluorescence-based imaging methods have been proven to significantly improve the detection of small, barely visible tumors and reduce the recurrence rate. Under ethical and economical pressure, new effective screening systems have to be developed to exploit and assess novel strategies for fluorescence photodetection in other areas. For this purpose, the chorioallantoic membrane (CAM) of the developing chick embryo is an attractive alternative model to the mammalian models.

MATERIALS & METHODS

Hypericin encapsulated into nanoparticles for the photodetection of ovarian metastases was evaluated in the CAM model with respect to vascular extravazation and tumor targeting and compared with free drug following intravenous administration.

RESULTS

To validate the CAM model as a valuable screening system for photodetection of cancer, we drew a comparison with results obtained on a conventional rodent model.

CONCLUSION

Rodent and CAM models led to the same conclusion regarding the benefits of nanoencapsulation to improve selective accumulation of drug in ovarian micrometastases.

Benefits of nanoencapsulation for the hypercin-mediated photodetection of ovarian micrometastases

The high recurrence and lethality of ovarian cancer at advanced stages is problematic, especially due to the development of numerous micrometastases scattered throughout the abdominal cavity. Fluorescence photodetection (PD) used in combination with surgical resection of malignant tissues has been suggested to improve recovery. Based on promising in vivo results for the detection of bladder cancer, hypericin (Hy), a natural photosensitizer (PS), stands as a good candidate for the photodetection of ovarian cancer. However, due to its hydrophobicity, systemic administration of Hy is problematic. Polymeric nanoparticles (NPs) help to overcome these delivery and stability problems and enable intravenous administration of Hy. In this study, Hy-loaded NPs of polylactic acid were produced with the following properties: (i) mean size of 268 nm, (ii) negative zeta potential, (iii) low residual surfactant and (iv) drug loading of 3.7 % (w/w). The potential of hypericin-loaded nanoparticles for the fluorescence photodetection of ovarian metastases in Fischer 344 rats bearing ovarian tumours was compared to free drug. The selectivity of Hy administered with both formulations was assessed first by fluorescence endoscopy, and then quantified after tissue extraction. The results showed an improved selective accumulation of Hy in ovarian micrometastases when NPs were used.

Fluorescence detection of protoporphyrin IX in living cells: a comparative study on single- and two-photon excitation

Photodynamic therapy (PDT) involves a combination of a lesion-localizing photosensitizer with light and has been established as a new modality for some medical indications. Much evidence has shown the correlation between subcellular localization of a photosensitizer with its photodynamic efficiency. However, the fluorescence of most photosensitizers in cells is weak and easily photobleached. We compare the effect of single-photon excitation (SPE) with that of two-photon excitation (TPE) on fluorescence detection of protoporphyrin IX (PpIX), a potent photosensitizer, in the PLC hepatoma cells in vitro. By using laser scanning confocal fluorescence microscopy, both fluorescence images and spectra of intracellular PpIX are studied with SPE of 405- and 488-nm lasers, and TPE of 800-nm femtosecond laser. The 405-nm laser is more efficient at exciting PpIX fluorescence than the 488-nm laser, but causes a considerable photobleaching of the PpIX fluorescence and induces weak autofluorescence signals of native flavins in the cells as well. The 800-nm TPE is found to significantly improve the quality of PpIX fluorescence images with negligible PpIX photobleaching and minimized endogenous autofluorescence, indicating the potential of 800-nm TPE for studying cellular localization of porphyrin photosensitizers for PDT.

Photodynamic diagnosis in urology: state-of-the-art

OBJECTIVES

To provide an overview on the methodology and clinical relevance of fluorescence diagnosis with exogenous fluorochromes or fluorochrome prodrugs in urology.

METHODS

The methodology is summarised on the basis of our experience and the relevant literature. Clinical results and perspectives are reported and concluded after we scanned and evaluated sources from PubMed. Search items were "aminolev*" or "hypericin" or "photodyn*" or "porphyrin" or "fluorescence" or "autofluorescence" and "bladder" or "prostate" or "kidney" or "peni*" or "condylo*". Some literature was also obtained from journals not indexed.

RESULTS

A large number of clinical trials have shown that photodynamic diagnosis (PDD) improves the ability to detect inconspicuous urothelial carcinoma of the bladder. Fluorescence diagnosis has recently been approved in Europe for the detection of bladder cancer after instillation of a hexaminolevulinate (Hexvix) solution. PDD is recommended by the European Association of Urology for the diagnosis of carcinoma in situ of the bladder. To date, the major weakness of PDD for the detection of bladder cancer is its relatively low specificity. Initial results with PDD for the detection of penile carcinoma, prostate cancer, kidney tumours, and urethral condylomata are promising.

CONCLUSIONS

To determine the actual impact of PDD on recurrence and progression rates of bladder cancer, further long-term observational studies are necessary. These studies also will clarify whether PDD is cost efficient.

Recent developments in fluorescence cystoscopy: do novel agents bring a benefit?

PURPOSE OF REVIEW

In flat bladder cancer and carcinoma in situ, and in multifocal papillary cancer, some smaller lesions may be overlooked at cystoscopy. For 10 years fluorescence cystoscopy has been promoted to solve these problems without wider acceptance. New fluorophobes now promise better clinical applicability.

RECENT FINDINGS

In prospective multicenter studies fluorescence cystoscopy shows significant improvement in the detection of flat bladder cancer and carcinoma in situ. It also permits more reliable identification of all neoplastic lesions with multifocal tumors, hence more precise removal and as a consequence lower recurrence rates.

SUMMARY

New agents bring a significant benefit. Hexyl-aminolevulinate offers more rapid urothelial accumulation, better fluorescence contrast and less photobleaching than previously used fluorophobes. It is simple to use in everyday practice and has a favorable toxicity profile.

Photodynamic Diagnostics and Noninvasive Bladder Cancer: Is It Cost-Effective in Long-Term Application? A Germany-Based Cost Analysis

OBJECTIVES

Noninvasive urothelial carcinoma of the bladder (UCB) causes an enormous economic burden to public health systems due to its life-long character and frequent recurrences. While white light (WL) cystoscopy is considered to be the gold standard for transurethral resection of the bladder, photodynamic diagnostic (PDD) has been shown to improve final outcome. Escalating healthcare costs warrant increased effectiveness in treating noninvasive UCB. No data based on assessment of costs have been published to date.

METHODS

A series of 301 patients with noninvasive UCB were randomized prospectively to standard WL or PDD transurethral resections of the bladder. Intravesical adjuvant therapy was administered as reflected in the appropriate guidelines. Expenditures of subsequent procedures and PDD-associated costs were assessed.

RESULTS

Median follow-up was 7.1 yr. Disease recurrence was found in 42% and 18% of WL and PDD patients, respectively (p=0.0003). In the WL group 2.0 and in the PDD group 0.8 transurethral resections of the bladder were noted per patient. In the WL group 1.0 and in the PDD group 0.3 recurring UCB occurred per patient, resulting in costs of 1750 euro per WL patient versus 420 euro per PDD patient in the follow-up period, respectively. Because a single expenditure of 135 euro was assessed for PDD, overall costs were significantly lower (by 1195 euro) in PDD patients. As the median follow-up was 7.1 yr, costs saved by PDD per patient per year were 168 euro.

CONCLUSION

Our data suggest that PDD significantly cut costs related to recurring UCB. Further studies are needed from an economic point of view.

Photodynamic therapy and cancer: a brief sightseeing tour

Photodynamic therapy (PDT) combines a drug (a photosensitiser or photosensitising agent) with a specific type of light to kill cancer cells. It is a minimally invasive treatment, with great potential in malignant disease and premalignant conditions. Following the administration of the photosensitiser, light of the appropriate wavelength is directed onto the abnormal tissue where the drug has preferentially accumulated. Upon light activation, the photosensitiser transfers its excess energy to molecular oxygen to produce an excited state (i.e., the highly reactive singlet oxygen) that causes oxidative damage at the site of its generation. The energy transfer occurs either directly to oxygen or through an indirect mechanism that requires the formation of intermediate radical species. Many photosensitisers have been developed, but only a few have been approved for therapy in humans. Basic research in model systems (animals, cell lines) has unravelled some fundamental cellular processes involved in the cell response to PDT. The exploitation of relevant molecular observations, the discovery and introduction of new sensitisers, the progress in the light delivery systems and light dosimetry are all concurring to the increase of PDT therapeutic efficacy. However, this field has not yet reached maturity. This review briefly analyses the relevant properties of most photosensitisers and their field of application. Special attention is dedicated to the effects observed in model cancer systems; speculation and suggestions of possible future research directions are also offered.

Superficial bladder cancer: part 1. Update on etiology, classification and natural history

Superficial 'nonmuscle-invasive' bladder tumors represent a heterogeneous group of cancers, which include those that are papillary in nature and limited to the mucosa (Ta), high grade, flat and confined to the epithelium (Tis) and those that invade the submucosa or lamina propria (T1). The natural history of these bladder cancers is that of disease recurrence and progression to higher grade and stage. Furthermore, recurrence and progression rates of superficial bladder cancer vary according to several tumor characteristics. The goal in the treatment of superficial bladder cancer is twofold: reducing tumor recurrence and the subsequent need for additional therapies, such as cystoscopy, transurethral resections, intravesical therapy and the morbidity associated with these treatments; and preventing tumor progression and the subsequent need for more aggressive therapy, such as radical cystectomy. The administration of intravesical chemotherapy and immunotherapy has become an important component in accomplishing these goals. This update is the first part of two articles reviewing important contemporary concepts in the etiology, classification and natural history of superficial bladder cancer, while part II of the series will review and highlight important aspects in management of superficial bladder cancer.

Fluorescence staining of human ovarian cancer tissue following application of 5-aminolevulinic acid: fluorescence microscopy studies

BACKGROUND AND OBJECTIVES

Application of 5-aminolevulinic acid (ALA) for fluorescence-guided second-look laparoscopy has been shown to be a promising new procedure in the early diagnosis of ovarian carcinoma metastases. However, for assessing the reliability of this method, information on the microscopic distribution of protoporphyrin IX (PP IX) in the tissue is needed. Additionally, the selectivity of PP IX uptake is essential for a potential photodynamic therapy (PDT) of ovarian cancer metastases.

STUDY DESIGN/MATERIALS AND METHODS

Thirty-six patients with epithelial ovarian cancer and two patients suffering from fallopian tube carcinoma underwent a laparoscopic second-look procedure 5 hours after the application of ALA. In 17 patients 36 fluorescence-guided biopsies were taken from fluorescing and non-fluorescing tissues for further evaluation. Fluorescence microscopy and digital image processing were utilized to determine the presence of PP IX fluorescence.

RESULTS

A specificity of 88% and a sensitivity of 100% with a negative predictive value of 100% and a positive predictive value of 91% were calculated for PP IX fluorescence on a microscopic level as marker for ovarian cancer metastases.

CONCLUSIONS

On a microscopic scale, ALA-induced PP IX fluorescence is confined to ovarian cancer tumor tissue sparing stromal tissues.

A case of anaphylactic shock possibly caused by intravesical Hexvix

BACKGROUND

We report a case of a 69-year-old Caucasian male who experienced a severe drop in blood pressure and a skin rash after fluorescence cystoscopy and transurethral resection of the prostate. The diagnostic agent used for fluorescence cystoscopy and suspected of causing the anaphylaxis was hexaminolevulinate hydrochloride (Hexvix).

INCIDENT

A profound fall in blood pressure associated with atrial fibrillation, the appearance of a rash, vomiting and transient loss of consciousness occurred immediately after surgery. The hypotension persisted for several hours despite intensive treatment. The reaction commenced approximately 5 h after exposure to Hexvix. There was an increase in serum tryptase (almost nine-fold) and a positive skin prick test to undiluted Hexvix.

CONCLUSION

The mechanism of the anaphylaxis is uncertain, but is considered likely to be a non-immunoglobulin E-mediated allergic reaction possibly caused by Hexvix. This is the first reported case of a severe allergic reaction after intravesical instillation of Hexvix.

Long-term benefit of 5-aminolevulinic acid fluorescence assisted transurethral resection of superficial bladder cancer: 5-year results of a prospective randomized study

PURPOSE

As shown in various studies 5-aminolevulinic acid (ALA) induces fluorescence of malignant and dysplastic bladder tissue and increases tumor detection rates by about 20%. However, data on the long-term benefits are sparse. Thus, the 5-year outcome data of a prospective randomized trial comparing patients who initially underwent bladder tumor resection (TUR) under standard white light or with ALA induced fluorescence were evaluated.

MATERIALS AND METHODS

A total of 115 patients with suspected superficial bladder cancer were randomized to undergo standard or ALA assisted TUR. After the second look TUR at 6 weeks patients were followed for a median of 39 (standard) and 42 (ALA) months.

RESULTS

Median time to first recurrence was 5 months in the standard and 12 months in the ALA group. Recurrence-free survival was 25% in the standard and 41% in the ALA group. The recurrence rate at 2, 12, 36 and 60 months after initial TUR was 41%, 61%, 73% and 75%, and 16%, 43%, 59% and 59% in the white light and ALA groups, respectively. The total number of recurrences was 82 in the standard and 61 in the ALA group. Tumor progression occurred in 9 patients in the standard and 4 in the ALA group. Cost analysis suggests a considerable economical advantage of ALA fluorescence assisted TUR compared to the standard procedure.

CONCLUSIONS

The initial advantage of improved tumor detection and decreased recurrence rates by ALA fluorescence assisted TUR is maintained for years, and effectively reduces morbidity and costs in patients with superficial bladder tumors.