Hexyl Aminolevulinate-Guided Fluorescence Cystoscopy In The Diagnosis Of Patients With Non-Muscle Invasive Bladder Cancer: A Review Based On Meta-Analysis

The principle of photodynamic diagnosis (PDD) is based on the interaction between a photosensitizing agent with a high uptake by tumor cells and light with an appropriate wavelength which is absorbed by the agent as high energy per photon and re-emitted with a lower energy per photon, thus, visualization is enhanced under under blue light. PDD offers improved visualization of bladder tumors while allowing a more complete transurethral resection. This may facilitate decreased recurrence rates and improved recurrence-free survival. The aim of this review was to evaluate the role of PDD on the diagnosis and treatment of bladder cancer in the light of current meta-analysis. Recently, 4 meta-analysis and a contemporary review have been published on the topic of PDD. Several prospective randomized studies have shown the superiority of PDD-guided cystoscopy over white light cystoscopy alone in tumor detection. PDD cystoscopy increased the detection of carcinoma in situ (CIS) by 25%-30%. All meta-analysis have found significantly reduced residual tumor rates with PDD. The main limitation of PDD is the false positive detection rate, which ranges from 1 to 26%. No differences in the rates of adverse events between PDD-guided cystoscopy and white light cystoscopy alone have been found in various randomized studies. Evidence exists in level 1 and 2 that PDD improves tumor detection especially for flat lesions such as CIS or dysplasia and reduces the rate of residual tumor in non-muscle invasive bladder cancer compared with white light cystoscopy alone. A translation of these findings into reduced disease recurrence rates is confirmed my most randomized trials. PDD does not seem to reduce disease progression.