Improving the efficiency of bladder cancer diagnostic cystoscopy with 5-ALA hexyl ester

This article presents the results of a clinical study that examined the diagnostic efficacy of fluorescent diagnostics (FD) of non-muscularinvasive bladder cancer using a photosensitizer of FD of malignant neoplasms – 5-aminolevulinic acid hexyl ester (5-ALA HE) compared with standard cystoscopy. The study involved 110 patients. The study began with intravesical administration of 50 ml of 0.2% solution of 5-ALA HE, the exposure time was 1 hour, after which the drug was removed from the organ. During the next hour, the mucous membranes were examined in two cystoscopy modes, followed by a standard transurethral resection of all urothelium sites with suspicion for tumor lesion based on white light and visible red fluorescence, and a control blind biopsy from the visually unchanged and non-fluorescent mucous tissue in each patient. The results of the study indicate the high effectiveness of the developed FD methodology with 5-ALA HE in detecting non-muscularinvasive bladder cancer during intravesical administration of the drug, due to selective accumulation of hexasens-induced PPIX in the tumor tissue compared with healthy mucosa. Compared with the results of standard cystoscopy, fluorescence diagnostics significantly increased diagnostic sensitivity by 24.4% (from 75.1% to 99.5%), diagnostic accuracy – by 15.8% (from 82.4% to 98.2%) and a negative predictive value – by 33.2% (from 65.8% to 99%) (p≤0.05). Additionally, a total of 37 (33.6%) patients was found to have 63 foci of fluorescence with a diameter of 2.5 to 3.0 mm. 59 of these were morphologically confirmed to contain cancer cells.