Fluorescence detection of bladder cancer: a review

Abstract

An effective therapeutic outcome in the treatment of bladder cancer is largely defined by its early detection. In this context, big expectations have been placed on the fluorescence-guided diagnosis of bladder cancer. This paper reviews the applications of endo- and exogenous fluorescence for early diagnosis of in situ carcinoma of the bladder. Despite certain advantages of autofluorescence, exogenous fluorescence, based on the intravesical instillation of fluorophores with the following visible light excitation, has been shown to be more effective in terms of sensitivity and specificity for detecting carcinoma in situ. The equipment consists of a slightly modified light source in order to choose between white (conventional endoscopy) or blue light (fluorescence endoscopy) excitation, and specific lenses, in order to enhance maximally the contrast between normal (blue) autofluorescence and red fluorescence from malignancies. Among exogenous fluorophores, a particular emphasis will be put on the 5-aminolevulinic acid (ALA), its ester derivative (h-ALA) and hypericin. These dyes demonstrated an excellent sensitivity above 90% and specificity ranging from 70% to 90%.