Fluorescence cytology of the urinary bladder

Characterization of the Peri-Membrane Fluorescence Phenomenon Allowing the Detection of Urothelial Tumor Cells in Urine

Simple Summary

To detect bladder cancer (BC), urinary cytology and cystoscopy are the primary diagnostic tests used. Urine cytology is non-invasive, easy to collect, with medium sensitivity and high specificity. It is an effective way to detect high-grade BC, but it is less effective on low-grade BC because the rate of equivocal results is much higher, making them difficult to detect. Despite the implementation of new diagnostics, urinary cytology and cystoscopy remain the gold standard. Instead of looking for new diagnostics, one of the new research areas is the improvement of urinary cytology. Recently, the fluorescent properties of plasma membranes of urothelial tumor cells, called peri-membrane fluorescence, found in urinary cytology have been shown to be useful in improving the early detection of BC. The main objective of this study was to characterize the peri-membrane fluorescence allowing the detection of urothelial tumor cells in urine.

Abstract

Urine cytology is non-invasive, easy to collect, with medium sensitivity and a high specificity. It is an effective way to detect high-grade bladder cancer (BC), but it is less effective on low-grade BC because the rate of equivocal results is much higher. Recently, the fluorescent properties of plasma membranes of urothelial tumor cells (UTC) found in urine cytology have been shown to be useful in improving the early detection of BC. This phenomenon is called peri-membrane fluorescence (PMF). Based on previous studies that have identified the PMF on UTCs, the main objective was to characterize this phenomenon. For this study, a software was specially created to quantify the PMF of all tested cells and different treatments performed. PMF was not found to be a morphological and discriminating feature of UTCs, all cells in shape and not from urine show PMF. We were able to highlight the crucial role of plasma membrane integrity in the maintenance of PMF. Finally, it was found that the induction of a strong cellular stress induced a decrease in PMF, mimicking what was observed in non-tumor cells collected from urine. These results suggest that PMF is found in cells able to resist this stress, such as tumor cells.

Fluorescence Emitted by Papanicolaou-Stained Urothelial Cells Improves Sensitivity of Urinary Conventional Cytology for Detection of Urothelial Tumors

Background

Urinary conventional cytology (UCCy) is easy to perform, but its low sensitivity, especially for low-grade urothelial neoplasms (LGUNs), limits its indications in the management of patients at risk of bladder cancer. The authors aim at obtaining a complementary test that would effectively increase the sensitivity of UCCy on voided urines by analyzing fluorescence of Papanicolaou-stained urothelial cells with no change of method in slide preparation.

Methods

In this retrospective study of 155 patients, 91 Papanicolaou-stained voided urines were considered satisfactory under fluorescence microscopy (FMi). The results of FMi were compared with UCCy (using transmission microscopy) and correlated to cystoscopy, histology and follow-up data.

Results

The results are given for all patients and for two groups of them according to the patients’ main complaints (group 1: 33 patients followed up for a previously treated bladder tumor; group 2: 58 patients with persistent urinary symptoms). Overall negative predictive value (NPV) and sensitivity of FMi were 100% vs. 73.7% and 64.3% respectively for UCCy (P = 0.0001). Sensitivity of FMi for LGUN was unexpectedly high with a value of 100% vs. 46.2% for UCCy (P = 0.0002). FMi was significantly superior to UCCy for detecting urothelial tumors in every group of patients and would allow a better characterization of atypical urothelial cells (AUCs) defined by the Paris System for Reporting Urine Cytology (TPS).

Conclusions

Because of its sensitivity and NPV of 100%, FMi could complement UCCy to screen voided urines allowing a better detection of primary urothelial tumors or early recurrences of previously treated urothelial carcinoma. Moreover, this “dual screening” would allow completing efficiently cystoscopy to detect flat dysplasia, carcinoma in situ (CIS) and extra bladder carcinoma.

Shedding Light on Bladder Cancer Diagnosis in Urine

Blue light cystoscopy (BLC) is the most recent clinical approach in the detection and diagnosis of bladder cancer, a common type of cancer with a high rate of recurrence. Representing a significant advance over previous approaches, this photodynamic diagnostic technique uses a photosensitiser prodrug as an adjunct to white light cystoscopy to enhance the in vivo detection of malignant tissues in the bladder based on their distinctive fluorescence. Whilst it does improve detection rates, BLC remains an invasive and costly procedure. Meanwhile, a variety of noninvasive urine detection methods and related microdevices have been developed, none of which have yet entered routine clinical use due to unsatisfactory sensitivity. Following a brief description of the current approaches and their limitations, we provide here a systematic review of a newer niche research aiming to develop a noninvasive adaptation of photodynamic diagnosis. The research to date surrounding the ex situ use of photosensitiser prodrugs for urinary diagnosis of bladder cancer is also discussed.

Inverted papilloma of the urinary bladder shows fluorescence on photodynamic diagnosis using 5-aminolevulinic acid

Photodynamic diagnosis (PDD) of non-muscle invasive bladder cancer using 5-aminolevulinic acid (5-ALA) has recently attracted attention as a diagnostic method for observing cancer lesions based on fluorescence emission using a fluorescent endoscope. However, there are few reports of false positives associated with benign bladder neoplasms. Here, we provide report of two cases of inverted papillomas of the bladder that were fluorescent on PDD using 5-ALA. In each case, a surface-smooth, pedunculated bladder tumor was observed, which fluoresced red on PDD after oral administration of 5-ALA. Histopathological findings demonstrated inverted papilloma of the bladder. Although inverted papilloma of the bladder is usually regarded as a benign neoplasm, some recent studies have revealed that it could be a risk factor for urothelial carcinoma. Our present report may support the hypothesis that inverted papilloma of the bladder has malignant potential.

Fluorescence cytology with 5-aminolevulinic acid in EUS-guided FNA as a method for differentiating between malignant and benign lesions (with video)

BACKGROUND

EUS-guided FNA (EUS-FNA) has been increasingly performed to obtain specimens for the pathological evaluation of patients with GI and pancreaticobiliary masses as well as lymphadenopathies of unknown origin. Photodynamic diagnosis by using 5-aminolebulinic acid (ALA) has been reported to be useful for enabling the visual differentiation between malignant and normal tissue in various cancers.

OBJECTIVE

To evaluate the diagnostic accuracy of fluorescence cytology with ALA in EUS-FNA.

DESIGN

A prospective study.

SETTING

A single center.

PATIENTS

A total of 28 consecutive patients who underwent EUS-FNA for the pathological diagnosis of a pancreaticobiliary mass lesion or intra-abdominal lymphadenopathy of unknown origin.

INTERVENTIONS

Patients were orally administered ALA 3 to 6 hours before EUS-FNA. The sample was obtained via EUS-FNA for fluorescence cytology and conventional cytology. A single gastroenterologist performed the fluorescence cytology by using fluorescence microscopy after the procedure, independently of the conventional cytology by pathologists.

MAIN OUTCOME MEASUREMENTS

The accuracy of fluorescence cytology with ALA in the differentiation between benign and malignant lesions by comparing the results of fluorescence cytology with the final diagnosis.

RESULTS

Of the 28 patients included in the study, 22 were considered as having malignant lesions and 6 patients as having benign lesions. Fluorescence cytology could correctly discriminate between benign and malignant lesions in all patients. Therefore, both the sensitivity and specificity of fluorescence cytology were 100% in our study.

LIMITATIONS

Fluorescence cytology was performed by only 1 gastroenterologist with a small number of patients.

CONCLUSION

Fluorescence cytology with ALA in EUS-FNA may be an effective and simple method for differentiating between benign and malignant lesions.

Protoporphyrin IX induced by 5-aminolevulinic acid in bladder cancer cells in voided urine can be extracorporeally quantified using a spectrophotometer

BACKGROUND

We evaluated the feasibility of photodynamic diagnosis of bladder cancer by spectrophotometric analysis of voided urine samples after extracorporeal treatment with 5-aminolevulinic acid (ALA).

METHODS

Sixty-one patients with bladder cancer, confirmed histologically after the transurethral resection of a bladder tumor, were recruited as the bladder cancer group, and 50 outpatients without history of urothelial carcinoma or cancer-related findings were recruited as the control group. Half of the voided urine sample was incubated with ALA (ALA-treated sample), and the rest was incubated without treatment (ALA-untreated sample). For detecting cellular protoporphyrin IX levels, intensity of the samples at the excitation wavelength of 405 nm was measured using a spectrophotometer. The difference between the intensity of the ALA-treated and ALA-untreated samples at 635 nm was calculated.

RESULTS

The differences in the bladder cancer group were significantly greater than those in the control group (p < 0.001). These differences were also significantly greater in patients with high-grade tumors than in those with low-grade tumors (p = 0.004), and also in patients with invasive bladder cancer than in those with noninvasive bladder cancer (p = 0.007). The area under the curve was 0.84. Sensitivity and specificity of the method were 82% and 80%, respectively.

CONCLUSIONS

We demonstrated that protoporphyrin IX levels in urinary cells treated with ALA could be quantitatively detected by spectrophotometer in patients with bladder cancer. Therefore, this cancer detection system has a potential for clinical use.

Photodynamic diagnosis of shed prostate cancer cells in voided urine treated with 5-aminolevulinic acid

Background

Past attempts at detecting prostate cancer (PCa) cells in voided urine by traditional cytology have been impeded by undesirably low sensitivities but high specificities. To improve the sensitivities, we evaluate the feasibility and clinical utility of photodynamic diagnosis (PDD) of prostate cancer by using 5-aminolevulinic acid (5-ALA) to examine shed prostate cancer cells in voided urine samples.

Methods

One hundred thirty-eight patients with an abnormal digital rectal exam (DRE) and/or abnormal prostate-specific antigen (PSA) levels were recruited between April 2009 and December 2010. Voided urine specimens were collected before prostate biopsy. Urine specimens were treated with 5-ALA and imaged by fluorescence microscopy and reported as protoporphyrin IX (PPIX) positive (presence of cells demonstrating simultaneous PPIX fluorescence) or PPIX negative (lack of cells demonstrating fluorescence).

Results

Of the 138 patients, PCa was detected on needle biopsy in 81 patients (58.7%); of these 81 patients with PCa, 60 were PPIX-positive (sensitivity: 74.1%). Although 57 patients did not harbor PCa by conventional diagnostic procedures, 17 of these at-risk patients were found to be PPIX-positive (specificity: 70.2%). PPIX–PDD was more sensitive compared with DRE and transrectal ultrasound and more specific compared with PSA and PSA density. The incidence of PPIX–PDD positivity did not increase with increasing total PSA levels, tumor stage or Gleason score.

Conclusions

To our knowledge, this is the first successful demonstration of PPIX in urine sediments treated with 5-ALA used to detect PCa in a noninvasive yet highly sensitive manner. However, further studies are warranted to determine the role of PPIX–PPD for PCa detection.

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.

Ex Vivo Fluorescence Imaging of Normal and Malignant Urothelial Cells to Enhance Early Diagnosis

Urinary cytology is a noninvasive and unconstraining technique for urothelial cancer diagnosis but lacks sensitivity for detecting low-grade lesions. In this study, the fluorescence properties of classical Papanicolaou-stained urothelial cytological slides from patients or from cell lines were monitored to investigate metabolic changes in normal and tumoral cells. Time- and spectrally-resolved fluorescence imaging was performed at the single cell level to assess the spectral and temporal properties as well as the spatial distribution of the fluorescence emitted by urothelial cells. The results reveal quite different fluorescence distributions between tumoral urothelial cells, characterized by a perimembrane fluorescence localization, and the normal cells which exhibit an intracellular fluorescence. This is not caused by differences in the fluorescence emission of the endogenous fluorophores NAD(P)H, flavoproteins or porphyrins but by various localization of the EA 50 Papanicolaou stain as revealed by both the spectral and time-resolved parameters. The present results demonstrate that the use of single-cell endofluorescence emission of Papanicolaou-stained urothelial cytological slides can allow an early ex vivo diagnosis of low-grade bladder cancers.

[Fluorescence cytology. Improvement of urinary cytology]

Urothelial cancer of the bladder is a frequent disease, and urinary cytology often is used as a routine diagnostic tool. But this technique has an impaired sensitivity in low-grade tumours, and as a subjective method it is highly dependent on the experience of the cytologist. Here we present the technique of fluorescence cytology as an improvement of conventional cytology. This method is potentially able to compensate for the disadvantages of urinary cytology as it is an automated process that uses the principles of 5-Ala-induced photodynamic diagnosis (PDD).

Integral spectrophotometric analysis of 5-aminolaevulinic acid-induced fluorescence cytology of the urinary bladder

OBJECTIVE

To evaluate whether tumour cells can be detected in bladder lavage fluid samples by an objective spectrofluorometric method, as 5-aminolaevulinic acid (ALA)-induced fluorescence endoscopy (AFE) and cytology are promising valuable tools for detecting transitional cell carcinoma of the urinary bladder (TCCB).

MATERIALS AND METHODS

After instilling ALA into the urinary bladder, lavage samples were collected and their sediments analysed spectroscopically under blue excitation at approximately 400 nm wavelength. During AFE, biopsies were taken. From 62 cases, 24 patients had a histologically confirmed TCCB (group A), 28 had a history of TCCB but no evidence of disease (group B) and 10 were negative for TCCB (group C).

RESULTS

Lavage sediments of all patients fluoresced in the green spectral range, typical of cellular autofluorescence. Sediments of all patients of group A caused red fluorescence peaking at 635 nm, indicating protoporphyrin IX (PPIX). The PPIX signals derived from bleaching spectra were significantly different between benign and malignant findings (P = 0.001). There was another red fluorescence peak at approximately 620 nm; in 19 cases its intensity exceeded the intensity of the PPIX signal.

CONCLUSIONS

Spectrofluorometric analysis of lavage sample sediments can be used to detect tumour-associated red fluorescence of PPIX in TCCB. Immediate significant and objective measurements are possible, which could be further automated for the rapid diagnosis of TCCB.