Predictors of false positives in 5-aminolevulinic acid-induced photodynamic diagnosis of bladder carcinoma: identification of patient groups that may benefit most from highly specific optical diagnostics

OBJECTIVES: To identify patient groups associated with a high probability of false positives in photodynamic diagnosis (PDD) of bladder cancer for which the use of highly specific optical instruments could be beneficial.

METHODS: This study includes the data of 306 patients. Under white light and 5-aminolevulinic acid-induced fluorescence light guidance, tumor locations were recorded, cold-cup biopsies were taken and tumors resected. Age, gender, recent transurethral resection of bladder tumor (TURBT), previous intravesical therapy, and urinary tract infections were examined for association with the false-positive rates in fluorescence cystoscopy by performing a multivariate analysis.

RESULTS: Significant univariate associations were found between false positives and gender (P = .009, odds ratio [OR] = 0.51), previous intravesical therapy (P = .03, OR = 1.78), previous BCG instillations (P = .03, OR = 2.05), and TURBT in the past 90 days (P = .01, OR = 2.37). In the multivariate regression model, female gender (male; P = .005, OR = 0.41) and TURBT within 90 days before PDD (P = .01, OR = 2.38) are significant independent predictors of false-positive findings in PDD.

CONCLUSIONS: Recent TURBTs and female gender are significant independent predictors of false positives in fluorescence cystoscopy.