Comparison of Efficiency of Photodynamic Diagnostics with Topical Use of the 3 and 15 Aminolevulinic Acid in the Detection of Vulvar Lesions

摘要

The objective of the study was evaluating the efficiency of the photodynamic method PDD (photodynamic diagnosis) in the detection of vulvar lesions when two concentrations of the photosensitizer were used ( 3%- and 15%-aminolevulinic acid ), as well as evaluating the efficiency of this method when compared to the efficiency of vulvoscopy, against the result of histological examination. Two concentrations of the 5-ALA cream ( aminolevulinic acid ) - 3% and 15% - were used in the PDD testing. The study group was divided into two subgroups A and B. In subgroup A the 15% eucerine - based cream was used. In subgroup B the 3% ALA gel with addition of 2% DMSO was used. The photosensitizer was applied to the vulva four to six hours before the examination. In order to obtain fluorescence, energy in the form of light whose wavelength was approximately 405 nm, and whose source was a SLED diode, was transmitted to vulvar tissue. The positive result of the exam was obtaining tissue fluorescence. All patients underwent vulvoscopy and a histological examination of tissue samples was performed in all cases. The efficiency of the photodynamic testing in subgroups A and B was compared with the efficiency of vulvoscopy, against the result of histological examination. Sensitivity, specificity, as well as positive and negative predictive values of the PDD examination and vulvoscopy in both subgroups, were evaluated. When the 15% ALA was used in detecting vulvar lesions, the photodynamic diagnostics was characterized by sensitivity of 100%, specificity of 92%, positive predictive value of 80%, negative predictive value of 100%, and correlation with the histopathological examination of 93.9%. When the 3% ALA was used, we observed: sensitivity of 100%, specificity of 91.4%, positive predictive value of 78.5%, negative predictive value of 100%, and correlation with the histopathological examination of 93.4%. Differences in the two subgroups were not statistically significant.