Clinical assessment of fluorescence cytoscopy during transurethral bladder resection in superficial bladder cancer

Is photodynamic diagnosis ready for introduction in urological clinical practice?

The aim of this review is to provide an up-to-date review of the available literature on photodynamic diagnosis (PDD) for nonmuscle-invasive bladder cancer, to present the technique in a comprehensive approach and, finally, to discuss the relevance of PDD in clinical practice in terms of indications, outcomes and its development trend. A literature search was conducted up to July 2012, using MEDLINE and EMBASE via Ovid databases to identify published studies on PDD for nonmuscle-invasive bladder cancer. Only English-language and human-based full manuscripts that reported on case series and studies with >40 participants, concerning clinical evidence of the technique, its efficacy and safety data were included. Evidence showed that PDD significantly improves detection of bladder cancer compared with standard white-light cystoscopy, having proven to be more effective for the diagnosis of carcinoma in situ. This condition seems to facilitate more complete resections, resulting in a lower residual tumor rate, which, in turn consecutively leads to higher recurrence-free survival rates. The literature search demonstrated that for mid- and long-term follow-up, PDD showed acceptable outcomes in terms of tumor detection, as well as lower residual tumor and lower recurrence rates compared with white-light cystoscopy. It has proven to be safe and well tolerated; the major limitations of PDD are its low specificity and elevated costs.

Photodynamic diagnosis of bladder cancer compared with white light cystoscopy: Systematic review and meta-analysis

OBJECTIVES

The aim of this study was to assess the test performance and clinical effectiveness of photodynamic diagnosis (PDD) compared with white light cystoscopy (WLC) in people suspected of new or recurrent bladder cancer.

METHODS

A systematic review was conducted of randomized controlled trials (RCTs), nonrandomized comparative studies, or diagnostic cross-sectional studies comparing PDD with WLC. Fifteen electronic databases and Web sites were searched (last searches April 2008). For clinical effectiveness, only RCTs were considered.

RESULTS

Twenty-seven studies (2,949 participants) assessed test performance. PDD had higher sensitivity than WLC (92 percent, 95 percent confidence interval [CI], 80-100 percent versus 71 percent, 95 percent CI, 49-93 percent) but lower specificity (57 percent, 95 percent CI, 36-79 percent versus 72 percent, 95 percent CI, 47-96 percent). For detecting higher risk tumors, median range sensitivity of PDD (89 percent [6-100 percent]) was higher than WLC (56 percent [0-100 percent]) whereas for lower risk tumors it was broadly similar (92 percent [20-95 percent] versus 95 percent [8-100 percent]). Four RCTs (709 participants) using 5-aminolaevulinic acid (5-ALA) as the photosensitising agent reported clinical effectiveness. Using PDD at transurethral resection of bladder tumor (TURBT) resulted in fewer residual tumors at check cystoscopy (relative risk [RR], 0.37, 95 percent CI, 0.20-0.69) and longer recurrence-free survival (RR, 1.37, 95 percent CI, 1.18-1.59), compared with WLC.

CONCLUSIONS

PDD detects more bladder tumors than WLC, including more high-risk tumors. Based on four RCTs reporting clinical effectiveness, 5-aminolaevulinic acid-mediated PDD at TURBT facilitates a more complete resection and prolongs recurrence-free survival.

Improved detection of nonmuscle invasive urothelial carcinoma of the bladder using pirarubicin endoscopy: a prospective, single-center preliminary study

BACKGROUND AND PURPOSE

Fluorescence cystoscopy (FC) with intravesical instillation of a photosensitizing agent has emerged as an adjunctive and safe diagnostic tool with high sensitivity and reasonable specificity; however, it has not been widely accepted, because it is time-consuming and expensive. The aim of the present study was to determine whether the use of the fluorescent dye pirarubicin [(2"R)-4'-O-tetrahydropyranyl doxorubicin] (THP) in endoscopy can improve detection of nonmuscle invasive urothelial carcinoma of the bladder.

PATIENTS AND METHODS

Forty-eight patients with known or suspected bladder urothelial carcinoma were enrolled in this prospective study between January 2008 and April 2009. The Storz D-light system was used to detect fluorescence 15 minutes after intravesical instillation with 30 mg THP. Endoscopic findings, histopathologic evaluation of biopsy lesions, and adverse effects of THP were recorded.

RESULTS

After THP uptake, the lesions appear bright orange under white light, and produce bright red fluorescence under blue light. Among 238 biopsies evaluated (84 malignant, 20 dysplasia, and 134 benign), sensitivity of overall tumors, carcinoma in situ (CIS), and dysplasia detection using FC was 96% (81/84), 100% (6/6), and 90% (18/20), respectively. The specificity of FC was 74.7% (115/154), and its false-positive rate was 32.5% (39/120). No significant systemic side effects or allergic reactions were observed other than a few cases of mild cystitis.

CONCLUSION

THP endoscopy may improve the detection of nonmuscle invasive urothelial carcinoma of the bladder, especially CIS and flat lesions. Results indicate that THP is a promising fluorescent dye for diagnosis and follow-up of nonmuscle invasive bladder carcinoma. Moreover, it is inexpensive, easily available, simple to administer, and is associated with few side effects.

Is photodynamic diagnosis using hypericin better than white-light cystoscopy for detecting superficial bladder carcinoma?

OBJECTIVE

To review the initial clinical results of photodynamic diagnosis (PDD) using hypericin (a new photosensitizer for PDD that helps to label flat urothelial tumours to facilitate biopsy) for the early detection of superficial bladder carcinoma, as flat noninvasive tumours of the bladder may be missed during conventional white-light cystoscopy (WLC) if there is bladder overdistension or ongoing cystitis.

PATIENT AND METHODS

Between 1 January 2001 and 30 October 2004, 41 consecutive patients (mean age 66.1 years, sd 9.1, range 46-81) had transurethral resection for bladder cancer. Hypericin was introduced intravesically for 2 h before cystoscopy. Immediately after WLC, fluorescence cystoscopy (FC) was used at the same location and the same bladder site inspected using violet light. FC findings, e.g. positive or negative red fluorescence, were documented for each specific bladder site examined, and the exact location sampled for biopsy.

RESULTS

The mean (sd, range) bladder capacity of the patients was 431 (86, 300-650) mL. In all, 179 biopsies were taken from the 41 patients; urothelial cancers were found in 41% (74) and 80% (33) had macroscopically visible bladder tumours; 40% (71) of the biopsies were positive under FC and 86% (61) of the 71 FC-positive biopsies showed cancer on histology. Twenty-five biopsies (14%) were positive on FC but not WLC. PDD testing with hypericin had a sensitivity of 82% (61/74) and specificity of 91% (95/105), vs WLC, at 62% (46/74) and 98% (103/105), respectively. The PDD test had a positive predictive value of 86% (61/71) and a negative predictive value of 88% (95/108), vs 96% (46/48) and 79% (103/131), respectively for WLC. There were no reports of significant complications after the procedure.

CONCLUSION

PDD using hypericin shows promise, as it has a higher sensitivity but equivalent specificity than WLC. It can be used to detect flat lesions not seen on WLC. PDD testing is also well tolerated with minimal side-effects.

Reduced specificity of 5-ALA induced fluorescence in photodynamic diagnosis of transitional cell carcinoma after previous intravesical therapy

OBJECTIVE

Photodynamic diagnosis (PDD) for the detection of bladder cancer has become a diagnostic tool in several hospitals. Several studies have reported different rates of false positive biopsies using 5-aminolevulinic acid induced fluorescence. In this study we evaluated the effect of previous intravesical therapy on the false positive biopsy rate.

METHODS

Two hours prior to endoscopy 1.5g ALA dissolved in 50ml 1.4% NaHCO(3) solution was instilled intravesically. For fluorescence excitation a blue light source (D-light, Karl Storz) was used. Under white and fluorescence light guidance, tumor locations were recorded, cold cup biopsies were taken and tumors were resected. Patients were divided into 3 groups, last intravesical therapy (IVT) less than 6 months prior to PDD, last IVT longer than 6 months before PDD and no previous IVT.

RESULTS

In total 917 biopsies were taken in 249 procedures of fluorescent and non-fluorescent areas. White light endoscopy revealed 270 and PDD 378 of in total 390 tumors, resulting in a sensitivity of 97% and specificity of 49% for PDD. Pathologic evaluation considered 270 fluorescent biopsies as false positive. The rate of false positive biopsies was 25.7% in the group No IVT, 30.6% in the group PDD-IVT >6 months, whereas in the group "within 6 months after intravesical therapy" the rate was 39.6% (p<0.025). When premalignant lesions such as dysplasia II are considered tumor the difference between the groups is even more significant (p<0.001).

CONCLUSIONS

The procedure has a high sensitivity for superficial bladder cancer and decreases the number of overlooked lesions. Recent intravesical therapy results in significantly more false positive fluorescent biopsies. Since patient outcome might predominantly be determined by the early detection and subsequent treatment of (pre)malignant tissue we suggest that PDD is justified even shortly after intravesical therapy.

Photodynamic diagnosis of ovarian cancer using hexaminolaevulinate: a preclinical study

The unfailing detection of micrometastases during surgery of patients suffering from ovarian cancer is mandatory for the optimal management of this disease. Thus, the present study aimed at determining the feasibility of detecting micrometastases in an ovarian cancer model using the intraperitoneal administration of the photosensitiser precursor hexaminolaevulinate (HAL). For this purpose, HAL was applied intraperitoneally at different concentrations (4-12 mM) to immunocompetent Fischer 344 rats bearing a syngeneic epithelial ovarian carcinoma. The tumours were visualised laparoscopically using both white and blue light (D-light, Karl Storz, Tuttlingen, Germany), and the number of peritoneal micrometastases detected through HAL-induced photodiagnosis (PD) was compared to standard white light visualisation. Fluorescence spectra were recorded with an optical fibre-based spectrofluorometer and the fluorescence intensities were compared to the protoporphyrin IX (PpIX) fluorescence induced by 5-aminolevulinic acid under similar conditions. The number of metastases detected by the PD blue light mode was higher than when using standard white light abdominal inspection for all applied concentrations. Twice as many cancer lesions were detected by fluorescence than by white light inspection. The hexyl-ester derivative produced higher PpIX fluorescence than its parent substance aminolevulinic acid at the same concentration and application time. Fluorescence contrast between healthy and cancerous tissue was excellent for both compounds. To overcome poor diagnostic efficiency and to detect peritoneal ovarian carcinoma foci in the large surface area of the human peritoneal cavity, HAL fluorescence-based visualisation techniques may acquire importance in future and lead to a more correct staging of early ovarian cancer.

Determination of the maximal tumor:normal bladder ratio after i.p. or bladder administration of 5-aminolevulinic acid in Fischer 344 rats by fluorescence spectroscopy in situ

The two major steps in our study on the treatment of bladder tumors by photodynamic therapy (PDT) were the development of a new bladder tumor model in Fischer rats by implantation of tumor cells and the use of fluorescence spectroscopy, a semi-quantitative and non-invasive method, in order to determine the time after general or local administration of a photosensitizer when the tumor:normal bladder ratio was at its highest. 5-Aminolevulinic acid (5-ALA) (250 mg/kg body weight) was injected i.p. or instilled directly into the bladder cavity for 1, 2 or 4 h and fluorescence was measured on normal and bladder tumor tissues every 30 min for 8-10 h after administration, with a special miniaturized optical-fiber captor. The better tumor:normal bladder ratios were 2.85+/-1.2 at 3.5 h after i.p. administration and 3.96+/-1.04 after bladder instillation for 4 h, respectively. These results were confirmed by fluorescence microscopy. PDT with the same dose of 5-ALA as in this pharmacokinetic study must also be carried out in order to compare the toxicity of the two administration routes of the photosensitizer and to determine which one is the better for this bladder tumor model.

[Fluorescence cystoscopy in bladder cancer: what future?]

Bladder transitional cell carcinoma, limited to the lamina propria, or superficial in 80% of the cases, is characterized by a high recurrence rate up to 70% in the three years following the first treatment. However, the constant evolution of the endoscopic techniques, useful to its diagnosis and treatment, contributed to reduce about by half this recurrence rate at three months. The actual development concerns new fluorescence detection methods, adapted to the standard endoscopic equipment. This new technique or fluorescence cystoscopy aims at improving the visual contrast between tumor and normal tissue in order to obtain a precise mapping of the diseased bladder. Thus, it allows to detect a carcinoma in situ (CIS) with a sensitivity around 80 to 90%. Its impact on the progression of the disease remains however to be demonstrated.

The use of 5-aminolaevulinic acid as a photosensitiser in photodynamic therapy and photodiagnosis

Photodynamic therapy (PDT) is a treatment for cancer and pre-malignant conditions, which involves the administration of a photosensitising agent followed by exposure of the tissue to light. 5-Aminolaevulinic acid (ALA) is a naturally occurring compound in the haem biosynthetic pathway, which is metabolised to a photosensitive product, protoporphyrin IX (PpIX). The major advantage of ALA when compared to synthetic photosensitisers is the rapid metabolism, which significantly reduces the period of cutaneous photosensitivity. This review focuses on the development of ALA as a photosensitiser in photodynamic therapy and photodiagnosis, and the wide range of clinical applications in which ALA is now being used as a therapeutic modality.

The history of photodetection and photodynamic therapy

Light has been employed in the treatment of disease since antiquity. Many ancient civilizations utilized phototherapy, but it was not until early last century that this form of therapy reappeared. Following the scientific discoveries by early pioneers such as Finsen, Raab and Von Tappeiner, the combination of light and drug administration led to the emergence of photochemotherapy as a therapeutic tool. The isolation of porphyrins and the subsequent discovery of their tumor-localizing properties and phototoxic effects on tumor tissue led to the development of modern photodetection (PD) and photodynamic therapy (PDT). This review traces the origins and development of PD and PDT from antiquity to the present day.