QUANTIFICATION OF 5-AMINOLEVULINIC ACID INDUCED FLUORESCENCE IMPROVES THE SPECIFICITY OF BLADDER CANCER DETECTION

Key transporters leading to specific protoporphyrin IX accumulation in cancer cell following administration of aminolevulinic acid in photodynamic therapy/diagnosis

The administration of aminolevulinic acid allow the formation and accumulation of protoporphyrin IX specifically in cancer cells, which then lead to photocytotoxicity following light irradiation. This compound, when accumulated at high levels, could also be used in cancer diagnosis as it would emit red fluorescence when being light irradiated. The concentration of protoporphyrin IX is pivotal in ensuring the effectiveness of the therapy. Studies have been carried out and showed the importance of various transporters in regulating the amount of these substrates by controlling the transport of various related metabolites in and out of the cell. There are many transporters involved and their expression levels are dependent on various factors, such as oxygen availability and iron ions. It is also important to note that these transporters may also have different expression levels depending on their organ. Understanding the mechanisms and the roles of these transporters are essential to ensure maximum accumulation of protoporphyrin IX, leading to higher efficiency in photodynamic therapy/diagnosis. In this review, we would like to discuss the roles of various transporters in protoporphyrin IX accumulation and how their involvement directly affect cancerous microenvironment.

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.

Fluorescence-guided transurethral resection of bladder tumours reduces bladder tumour recurrence due to less residual tumour tissue in Ta/T1 patients: a randomized two-centre study

OBJECTIVES

•To compare the bladder tumour recurrence rate in stage Ta and T1 tumours after conventional transurethral resection of the bladder in white light (WL TURB) and after fluorescence-guided TURB (HAL TURB) using hexaminolaevulinate (HAL: Hexvix®, Photocure, Norway) for photodynamic diagnosis during 12 months of follow-up. •As secondary objectives, to relate the tumour recurrence rate to fluorescence-detected residual tumour after WL TURB and to assess the false positive rate.

PATIENTS AND METHODS

•This was a prospective, comparative, randomized, open-label study carried out in hospital outpatient urology clinics and the operating theatre. A total of 233 patients presenting with suspected superficial bladder tumour were recruited. Both patients with new tumours and patients with recurrent tumours were included. •The study duration was 2.5 years with follow-up cystoscopic investigations at 4, 8 and 12 months. •Patients were randomized to cystoscopy and WL TURB (118 patients) or WL TURB followed immediately by HAL TURB (115 patients). Cystoscopy/TURB and bladder biopsies were performed under general anaesthesia. No patients had intravesical chemotherapy immediately after TURB. •Recurrences were verified histologically.

RESULTS

•The two groups were similar regarding age and previous bladder cancer history. •In all, 90 patients from the HAL TURB group had bladder tumour. Fluorescence-guided cystoscopy after complete WL TURB identified residual tumour tissue in 44 of 90 patients (49%). In 37 of 83 (45%) residual Ta tumour was found; in three of seven residual T1 was found and in four cases carcinoma in situ. •True (and false) positive detection rate of photodynamic diagnosis was 64% (25%) and of white light 83% (16%). •In all, 145 patients were eligible for analysis of tumour recurrence. Twelve patients had their last follow-up after 4 months. The recurrence rate in patients followed for 12 months was 47.3% (35/74) after WL TURB and 30.5% (18/59) after HAL TURB (P= 0.05). •Kaplan-Meier analyses comprising data from all 145 patients showed that the recurrence-free period was significantly longer in the HAL TURB group than in the WL TURB group (P= 0.02).

CONCLUSION

•WL TURB often leaves residual tumour in the bladder. HAL TURB improves the detection of Ta/T1 tumours of the bladder resulting in more complete TURB procedures and thus a reduced recurrence rate.

Clinical grading of oral mucosa by curve-fitting of corrected autofluorescence using diffuse reflectance spectra

BACKGROUND

Laser-induced autofluorescence (LIAF) and diffuse reflectance (DR) were collectively used in this clinical study to improve early oral cancer diagnosis and tissue grading.

METHODS

LIAF and DR emission from oral mucosa were recorded on a fiber-optic spectrometer by illumination with a 404-nm diode laser and tungsten halogen lamp in 36 healthy volunteers and 40 lesions of 20 patients.

RESULTS

Absorption dips in LIAF spectra at 545 and 575 nm resulting from changes in oxygenated hemoglobin were corrected using DR spectra of the same site. These corrected spectra were curve-fitted using Gaussian spectral functions to determine constituent emission peaks and their relative contribution. The Gaussian peak intensity and area ratios F500/F635 and F500/F685 were found to be useful indicators of tissue transformation. The diagnostic capability of various ratios in differentiating healthy, hyperplastic, dysplastic, and squamous cell carcinomas (SCCs) were examined using discrimination scatterplots.

CONCLUSIONS

The LIAF/DR technique, in conjunction with curve-fitting, differentiates different grades of dysplasia and SCC in this clinical trial and proves its potential for early detection of oral cavity cancer and tissue grading.

Preferential accumulation of 5-aminolevulinic acid-induced protoporphyrin IX in breast cancer: a comprehensive study on six breast cell lines with varying phenotypes

We describe the potential of 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) fluorescence as a source of contrast for margin detection in commonly diagnosed breast cancer subtypes. Fluorescence intensity of PpIX in untreated and ALA-treated normal mammary epithelial and breast cancer cell lines of varying estrogen receptor expression were quantitatively imaged with confocal microscopy. Percentage change in fluorescence intensity integrated over 610-700 nm (attributed to PpIX) of posttreated compared to pretreated cells showed statistically significant differences between four breast cancer and two normal mammary epithelial cell lines. However, a direct comparison of post-treatment PpIX fluorescence intensities showed no differences between breast cancer and normal mammary epithelial cell lines due to confounding effects by endogenous fluorescence from flavin adenine dinucleotide (FAD). Clinically, it is impractical to obtain pre- and post-treatment images. Thus, spectral imaging was demonstrated as a means to remove the effects of endogenous FAD fluorescence allowing for discrimination between post-treatment PpIX fluorescence of four breast cancer and two normal mammary epithelial cell lines. Fluorescence spectral imaging of ALA-treated breast cancer cells showed preferential PpIX accumulation regardless of malignant phenotype and suggests a useful contrast mechanism for discrimination of residual cancer at the surface of breast tumor margins.

Real-time intraoperative fluorescence imaging system using light-absorption correction

We present a novel fluorescence imaging system developed for real-time interventional imaging applications. The system implements a correction scheme that improves the accuracy of epi-illumination fluorescence images for light intensity variation in tissues. The implementation is based on the use of three cameras operating in parallel, utilizing a common lens, which allows for the concurrent collection of color, fluorescence, and light attenuation images at the excitation wavelength from the same field of view. The correction is based on a ratio approach of fluorescence over light attenuation images. Color images and video is used for surgical guidance and for registration with the corrected fluorescence images. We showcase the performance metrics of this system on phantoms and animals, and discuss the advantages over conventional epi-illumination systems developed for real-time applications and the limits of validity of corrected epi-illumination fluorescence imaging.

Improved diagnosis of oral premalignant lesions in submucous fibrosis patients with 5-aminolevulinic acid induced PpIX fluorescence

We investigate the possibility of using ALA-derived PpIX fluorescence spectroscopy for the detection of epithelial hyperkeratosis (EH) or epithelial dysplasia (ED) lesions in oral submucous fibrosis (OSF) patients that could not be found by autofluorescence spectroscopy. Twenty percent of ALA solution gel was applied onto oral neoplasia and surrounding normal tissue [normal oral mucosa (NOM)] for 90 min. Fluorescence emission spectra were measured under 410 nm excitation. Generally, the most intense fluorescence emission peaks occurred at 460 and 630 nm. The ratios of the area under red peak (630+/-10 nm) to the area under blue peak (460+/-10 nm), denoted as RB, were calculated. We found that OSF mucosa has the lowest RB value, followed by NOM, EH on OSF, and ED on OSF. An ANOVA test showed significant differences between OSF, NOM, EH on OSF, and ED on OSF (p<0.05). However, measurements of autofluorescence (i.e., before ALA application) show no significant differences between OSF, NOM, EH on OSF, and ED on OSF (ANOVA test, p>0.05). These results indicate that ALA-induced PpIX fluorescence spectroscopy could be used to identify the premalignant lesions on oral fibrotic mucosa, which could not be found by autofluorescence.

Study of interaction of hypericin and its pharmaceutical preparation by fluorescence techniques

We report the detection of interactions between a photosensitizer, hypericin (HY), and its solvent system prepared with a formulation additive, polyvinylpyrrolidone (PVP), a commonly used pharmaceutical excipient. Fluorescence correlation spectroscopy (FCS) and fluorescence lifetime imaging microscopy (FLIM) were used to study aggregation and binding of HY in the presence of PVP. Digitized fluorescence endoscopic imaging (DFEI) was used to study the effect of the pharmaceutical formulation in the in vivo tumor implanted chick chorioallantoic membrane (CAM) model. The results presented reveal the coordination of HY-PVP binding, HY disaggregation in the presence of PVP, and strengthened HY tumor uptake selectivity. PVP is thus suggested as a potential adjuvant to previously investigated N-methyl pyrrolidone (NMP) in the HY delivery system as well as a replacement for the conventionally used albumin in the HY bladder instillation fluids preparation for clinical use.

Endoscopic image analysis of photosensitizer fluorescence as a promising noninvasive approach for pathological grading of bladder cancer in situ

Our aim is to apply image analysis on photosensitizer fluorescence and compare the relationship between histopathology and endoscopic fluorescence imaging. The correlation between hypericin fluorescence and histopathology of diseased tissue was explored in a clinical study involving 58 fluorescence cystoscopic images from 23 patients. Based on quantification of fluorescence colorimetric parameters extracted from the image analysis, diagnostic functions were developed to pathologically classify the bladder cancer. Our preliminary results show that the differences in fluorescence intensity ratios among the three different grades of bladder cancer are statistically significant. The results also show a decrease in macroscopic fluorescence intensity that correlated with higher cancer grades. By combining both the red-to-green and red-to-blue fluorescence intensity ratios into a 2-D scatter plot and defining diagnostic linear discrimination functions on the data points, this technique is able to yield an average sensitivity and specificity of around 68.6% and 86.1%, respectively, for pathological cancer grading of the three different grades of bladder cancer in our study. We conclude that our proposed approach in applying colorimetric intensity ratio analysis on hypericin fluorescence shows potential to optically grade bladder cancer in situ.

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.

In vivo bladder imaging with microelectromechanical-systems-based endoscopic spectral domain optical coherence tomography

We report the recent technical improvements in our microelectromechanical systems (MEMS)-based spectral-domain endoscopic OCT (SDEOCT) and applications for in vivo bladder imaging diagnosis. With the technical advances in MEMS mirror fabrication and endoscopic light coupling methods, the new SDEOCT system is able to visualize morphological details of the urinary bladder with high image fidelity close to bench-top OCT (e.g., 10 mum12 mum axial/lateral resolutions, >108 dB dynamic range) at a fourfold to eightfold improved frame rate. An in vivo animal study based on a porcine acute inflammation model following protamine sulfate instillation is performed to further evaluate the utility of SDEOCT system to delineate bladder morphology and inflammatory lesions as well as to detect subsurface blood flow. In addition, a preliminary clinical study is performed to identify the morphological features pertinent to bladder cancer diagnosis, including loss of boundary or image contrast between urothelium and the underlying layers, heterogeneous patterns in the cancerous urothelium, and margin between normal and bladder cancers. The results of a human study (91% sensitivity, 80% specificity) suggest that SDEOCT enables a high-resolution cross-sectional image of human bladder structures to detect transitional cell carcinomas (TCC); however, due to reduced imaging depth of SDEOCT in cancerous lesions, staging of bladder cancers may be limited to T1 to T2a (prior to muscle invasion).

Intérêt des marqueurs urinaires dans le diagnostic et le suivi des tumeurs urothéliales de vessie

Urothelial bladder tumours require regular surveillance: cystoscopy associated with urine cytology are reference examinations. Several new markers currently under evaluation or already validated have recently been proposed to replace cytology and potentially reduce or even replace unnecessary cystoscopies. The biological fluid studied for all of these markers is the same as that of urine cytology, i.e. urine. The authors review the results of recent studies on these new urinary markers. The results of these markers demonstrate a better global sensitivity than urine cytology, but often a lower specificity. In the majority of cases, these tests are performed during patient follow-up (NMP22, BTA, CYFRA 21-l., etc.), but do not replace cystoscopy, due to a large number of false-positives. Other techniques, such as FISH, uCyt+ or microsatellites appear to be more promising, especially for the diagnosis of low-grade tumours. The best solution in practice may consist of a combination of several markers to further improve sensitivity and to decrease the false-positive rate responsible for unnecessary cystoscopies.

Fluorescence spectroscopy combined with 5-aminolevulinic acid-induced protoporphyrin IX fluorescence in detecting oral premalignancy

BACKGROUND

Early detection of premalignant/malignant lesions in the oral cavity can certainly improve the patient's prognosis. This study presents fluorescence imaging with the topical application of 5-aminolevulinic as a way to improve detection of various oral tissue pathologies. This procedure depends mainly on comparing the intensity of red and green fluorescence emitted from tissues during examination.

MATERIALS AND METHODS

Seventy-one patients who presented with clinically suspicious oral leukoplakia were recruited for this study. Each of the patients was required to have 5-aminolevulinic acid in the form of mouth rinse prior to fluorescence imaging. Following this a surgical biopsy was acquired from the exact examination site. The results of the fluorescence spectroscopy have been compared with histopathology.

RESULTS

A Student's t-test was applied to test the viability of the ratio between red and green fluorescence. The red-to-green ratio was found to increase significantly when the lesion was identified as dysplastic or carcinoma in situ. By applying a threshold line to discriminate between normal and dysplastic lesions; a sensitivity of 83-90% and specificity of 79-89% were obtained.

CONCLUSION

Fluorescence spectroscopy combined with 5-aminolevulinic acid-induced protoporphyrin IX was found as a valuable tool in the diagnosis of oral premalignancy. This technique offers the potential to be advantageous over other non-optical techniques in terms of providing real-time diagnosis, in situ monitoring, cost effectiveness and more tolerated by patient compared to surgical biopsy.

The potential application of chlorin e6–polyvinylpyrrolidone formulation in photodynamic therapy

Much research has been focused on developing effective drug delivery systems for the preparation of chlorins as potential photosensitizers for PDT. This report describes the evaluation of a new water-soluble formulation of chlorin e6 consisting of a complex of trisodium salt chlorin e6 and polyvinylpyrrolidone (Ce6-PVP) for application in photodynamic therapy (PDT) with 2 specific aims: (i) to investigate its fluorescence kinetics in skin, normal and tumor tissue after intravenous administration, and (ii) to investigate its PDT efficacy. Our results demonstrate that this new formulation possesses photosensitizing properties with rapid accumulation in tumor tissue observed within 1 h after intravenous administration. Although high selectivity in tumor tissue was found between the period of 3 and 6 h, the efficacy of Ce6-PVP mediated PDT was best at 1 h drug-light interval. It is suggested that, the extent of tumor necrosis post PDT is dependent on the plasma concentration of Ce6-PVP, implying a vascular mediated cell death mechanism. A faster clearance rate of Ce6-PVP from the skin of nude mice was observed compared to Ce6. The new formulation of Ce6-PVP seems to show promise as an effective therapeutic agent.

FLUORESCENCE GUIDED OPTICAL COHERENCE TOMOGRAPHY FOR THE DIAGNOSIS OF EARLY BLADDER CANCER IN A RAT MODEL

PURPOSE

We describe the technique of fluorescence image guided optical coherence tomography (FG-OCT). We examined its ability to enhance specificity and sensitivity for the noninvasive diagnosis of early bladder cancer.

MATERIALS AND METHODS

Transitional cell carcinoma was developed in 54 Fisher 344 female rats by intravesical methyl-nitroso-urea instillations. Two or three rats were diagnosed sequentially by 5-ALA (5-aminolevulinic acid hydrochloride) induced fluorescence imaging, cross-sectional OCT and histological microscopy weekly during weeks 11 to 33 following initial methyl-nitroso-urea instillation to track the course of carcinogenesis.

RESULTS

The specificity of fluorescence detection was significantly enhanced by FG-OCT (53% and 93%, respectively, p <0.0001). The sensitivity of fluorescence detection and FG-OCT was 79% and 100%, respectively.

CONCLUSIONS

FG-OCT cystoscopy has the potential to diagnose early bladder cancer with high sensitivity and specificity with drastically decreased imaging time compared to that of white light guided OCT cystoscopy.

Bladder cancer: Epidemiology, staging and grading, and diagnosis

Bladder cancer is a heterogeneous disease with a variable natural history. At one end of the spectrum, low-grade Ta tumors have a low progression rate and require initial endoscopic treatment and surveillance but rarely present a threat to the patient. At the other extreme, high-grade tumors have a high malignant potential associated with significant progression and cancer death rates. In the Western world, bladder cancer is the fourth most common malignancy in men and the eighth most common in women. In Europe and the United States, bladder cancer accounts for 5% to 10% of all malignancies in men. The risk of developing bladder cancer at <75 years of age is 2% to 4% for men and 0.5% to 1% in women compared with the risk of lung cancer, for example, which is 8% in men and 2% in women. For the geographic and temporal comparison of bladder cancer incidence, it is crucial to separate the low-grade from the high-grade tumors. In epidemiologic studies on risk factors for bladder cancer, it is important to distinguish the low-grade Ta tumors from high-grade carcinoma in situ (CIS) and tumors >T1. Current studies do not support the routine screening for bladder cancer. However, prospective long-term studies are required to evaluate the benefits of bladder cancer screening, particularly in those at high risk. After assessing all available evidence, the Epidemiology and Diagnosis Committee has made recommendations on various diagnostic issues, including pathologic evaluation, urinary cytology, and imaging studies. Optimal resection techniques, role of repeat transurethral resection in high-grade T1 tumors, random bladder biopsy, and prostatic urethral biopsy are discussed, and appropriate recommendations are made according to the strength of available evidence.

Improved preoperative tumor staging by 5-aminolevulinic acid induced fluorescence laparoscopy

BACKGROUND

We report our data in 35 patients who underwent preoperative conventional and fluorescence-based staging laparoscopy. We use the data to address the questions of whether fluorescence examination increases the yield of metastatic lesions and alters treatment intervention.

METHODS

Fluorescence laparoscopy was successfully performed in 30 patients with GI malignancies. After sensitization with 5-aminolevulinic acid, conventional white-light mode and fluorescence-light laparoscopies were sequentially performed. A suspected malignancy was biopsied.

OBSERVATIONS

In 5 patients, examinations were incomplete because of adhesions. In 9 of 10 patients, hepatic or peritoneal metastases were detected by white-light examination. In 4 of these 9, blue-light examination yielded more metastatic lesions. In one patient with no lesions by white- or blue-light examination, surgery revealed hepatic metastasis in a location not accessible to laparoscopic examination. In 18 patients, surgery confirmed the absence of metastatic lesions.

CONCLUSIONS

A fluorescence, blue-light examination yielded more lesions than the conventional white-light examination but did not alter treatment intervention and did not enhance yield when metastatic lesion is in an inaccessible location. Continued research should focus on whether treatment intervention will be altered by the fluorescence examination.

Assessment of photosensitizer dosimetry and tissue damage assay for photodynamic therapy in advanced-stage tumors

Photodynamic therapy (PDT) efficacy is a complex function of tissue sensitivity, photosensitizer (PS) uptake, tissue oxygen concentration, delivered light dose and some other parameters. To better understand the mechanisms and optimization of PDT treatment, we assessed two techniques for quantifying tissue PS concentration and two methods for quantifying pathological tumor damage. The two methods used to determine tissue PS concentration kinetic were in vivo fluorescence probe and ex vivo chemical extraction. Both methods show that the highest tumor to normal tissue PS uptake ratio appears 4 h after PS administration. Two different histopathologic techniques were used to quantify tumor and normal tissue damage. A planimetry assessment of regional tumor necrosis demonstrated a linear relationship with increasing light dose. However, in large murine tumors this finding was complicated by the presence of significant spontaneous necrosis. A second method (densitometry) assessed cell death by nuclear size and density. With some exceptions the densitometry method generally supported the planimetry results. Although the densitometry method is potentially more accurate, it has greater potential subjectivity. Finally, our research suggests that the tools or methods we are studying for quantifying PS levels and tissue damage are necessary for the understanding of PDT effect and therapeutic ratio in experimental in vivo tumor research.

The use of digitized endoscopic imaging of 5-ALA-induced PPIX fluorescence to detect and diagnose oral premalignant and malignant lesions in vivo

5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PPIX) fluorescence has shown an outstanding sensitivity for the assessment of oral lesions, but its application was hampered by low specificity due to the high false-positive rates. The purpose of our study was to explore the feasibility of quantifying PPIX fluorescence images to improve the diagnostic specificity for detecting early oral lesions in vivo. A digitized 5-ALA-mediated endoscopic imaging system was utilized to acquire PPIX fluorescence images from in vivo oral tissues. Forty-nine patients (118 biopsies) with known or suspected premalignant or malignant oral lesions were recruited for ALA-PPIX fluorescence endoscopic imaging. The red and blue channels of PPIX fluorescence images were digitized and stored for fluorescence quantification. The red-to-blue intensity ratios were calculated from the fluorescence images to correlate with histologic findings of the biopsies. The results showed that normal oral mucosa exhibited blue color of the back-scattered excitation light in the fluorescence images, whereas the suspicious lesions displayed bright reddish fluorescence. Applying the red-to-blue intensity ratio (I(R)/I(B)) as a diagnostic algorithm yielded a sensitivity of 92% and 98%, and specificity of 96% and 96%, for separating benign tissue from dysplasia, and cancer tissue, respectively, and a sensitivity and specificity of 98% and 92%, respectively, for differentiating cancer tissue from dysplasia in the oral cavity. Our study demonstrates that quantifying ALA-PPIX fluorescence endoscopic images associated with the red-to-blue intensity ratio as a diagnostic algorithm can provide good differentiation between the different stages of oral premalignancy and malignancy (p<0.0001, unpaired 2-sided Student's t-test), and thus has a potential to significantly improve the noninvasive diagnosis and evaluation of early oral neoplasia in vivo.

Fluorescence cytology of the urinary bladder

OBJECTIVES

To assess, on the basis of the tumor-associated fluorescence characteristics of 5-aminolevulinic acid-induced fluorescence endoscopy, the value of fluorescence microscopy and compare it with standard cytologic techniques. 5-Aminolevulinic acid-induced fluorescence endoscopy has proved to be a valuable detection method with a high sensitivity for the endoscopic diagnosis of bladder cancer.

METHODS

We instilled 1.5 g of 5-aminolevulinic acid, dissolved in 50 mL of 5.7% sodium monohydrogen phosphate, into the urinary bladder of 162 patients with suspected transitional cell carcinoma 2 to 3 hours before endoscopy. A lavage solution was obtained for urinary cytology and for fluorescence cytology. The sediments were evaluated for tumor cells.

RESULTS

Transitional cells suspicious for tumor demonstrated the red 5-aminolevulinic acid-induced protoporphyrin IX fluorescence under the microscope. Fluorescence cytology identified 50 of 58 histologically confirmed neoplastic lesions (G1, 14 of 17; G2, 12 of 14; G3, 15 of 16; and carcinoma in situ, 9 of 11). With urinary cytology, we identified 46 of 58 histologically confirmed tumor lesions (G1, 9 of 17; G2, 12 of 14; G3, 15 of 16; and carcinoma in situ, 10 of 11). The sensitivity of fluorescence cytology was 86% and that of urinary cytology 79%. The specificity of fluorescence cytology was 75% and that of urinary cytology 88%.

CONCLUSIONS

Fluorescence cytology promises to be an effective procedure for the diagnosis of bladder cancer, especially in highly differentiated and flat premalignant tumor lesions. Automated analysis for an objective and a reproducible result appears possible.

Detection of squamous cell carcinomas and pre-cancerous lesions in the oral cavity by quantification of 5-aminolevulinic acid induced fluorescence endoscopic images

BACKGROUND AND OBJECTIVES

Studies of 5-aminolevulinic acid-induced protoporphyrin IX fluorescence have shown a sensitivity of 95-100% for oral cancer diagnosis, but the specificity is only about 50-60%. Here, we explore the applicability of quantifying PPIX fluorescence images to improve the diagnostic specificity and detect early oral lesions.

STUDY DESIGN/MATERIALS AND METHODS

PPIX Fluorescence endoscopy and imaging were performed on 28 patients with a known or suspected premalignant or malignant oral cavity lesion. A total of 70 biopsies were taken from the tissue sites imaged for histological analysis. The red-to-blue and red-to-green intensity ratios were calculated from the fluorescence images to correlate with histology.

RESULTS

Suspicious lesions display bright reddish fluorescence, while normal mucosas exhibit blue color background in the fluorescence images. The red-to-blue and red-to-green intensity ratios of malignant tissues are larger than those of benign tissues. Combining the two ratio diagnostic algorithms yields a sensitivity and specificity of 95% and 97%, respectively, exceeding each diagnostic algorithm alone for discriminating malignant tissue from benign tissue.

CONCLUSIONS

Quantifying PPIX fluorescence endoscopic images combined with the ratio diagnostic algorithms developed in this study has the potential to significantly improve the noninvasive diagnosis of oral cavity lesions in vivo.

DNA alterations in body fluids as molecular tumor markers for urological malignancies

OBJECTIVES

DNA-based tumor markers are characterized by unique specificity rendering them an attractive target for molecular diagnosis of cancer in body fluids like blood serum/plasma and urine. Both cell-free tumor DNA circulating in plasma/serum and cellular tumor DNA are detectable by minimally invasive measures.

METHODS

Three main detection methods, microsatellite analysis, mutation analysis in genomic or mitochondrial DNA and gene promoter hypermethylation analysis are applied. Detection of gene promoter hypermethylation by methylation-specific PCR enables the best methodical sensitivity requiring a ratio of tumor DNA within normal DNA of less than 1:1000.

RESULTS/CONCLUSIONS

Tumor DNA derived from renal cell carcinoma, bladder cancer or prostate cancer is detectable in considerably more than 50% of plasma/serum samples and more than 70% of urine samples from these patients. Because the targeted DNA alterations are absent or very rare in controls, the specificity of DNA-based tumor detection methods reaches almost 100%. Although the methodology currently is experimental, automatization will make it easier and less expensive. This review is focused on the potential clinical value of DNA-based analysis of body fluids for the initial diagnosis and the follow-up of urologic cancer patients.

New diagnostic and prognostic tools in bladder cancer

Many efforts have been made to increase the detection rates and to predict the outcome of bladder cancer. Although to date cystoscopy remains the gold standard method for the detection of new or recurrent bladder cancer, its limitations were emphasized by the results of studies using fluorescence endoscopy that showed an increased detection rate and decreased recurrence after tumor resection. Urine cytology has high specificity and is used routinely as an adjunct to cystoscopy to detect invisible tumors. However, to improve on the low sensitivity of urine cytology, a number of marker tests have been developed. Optimal diagnostic accuracy appears to result from the synergistic combination of cytological markers with urine cytology. The evaluation of new and previously reported markers remains a very active field, but is still limited to inconclusive studies. Tissue and DNA microarrays represent a technological step forward for the analysis of a large number of markers and cohorts of patients that will be required definitively to establish the clinical utility of prognostic tests.