Two Diagnostic Criteria of Optical Spectroscopy for Bladder Tumor Detection: Clinical Study using 5-ALA induced fluorescence and Mathematical Modeling.

The study proposes to improve bladder cancer diagnosis by (i) photodynamic diagnosis (PDD) using red-light excitation (632.8 nm) of 5-ALA induced-protoporphyrin IX in 9 patients' bladder associated to the analysis of two types of signals to improve the diagnostic accuracy, and (ii) numerical modeling of scattering coefficient for providing biological explanations of the results obtained.

Two modalities of the bladder cancer spectral diagnosis are presented: conventional PDD and intensity assessment of the diffusely reflected laser light by fiber-optic spectroscopy. Experiments are done in clinical conditions and as a series of numerical simulations.

High-grade cancerous bladder tissues display twice a higher relative fluorescence intensity (mean value 1, n = 9) than healthy (0.39, n = 9), dysplastic (0.44, n = 5) tissues and CIS (0.39, n = 2). The laser back-scattering signal allows to discriminate most effectively high-grade cancerous and dysplastic tissues from normal. Numerical modeling of diffuse reflectance spectra reveals that spectral behavior of the back-scattered light depends on both, nuclear size and nuclear density of tumoral cells.

Unlike the fluorescence signal, where its value is higher in the case of pathological tissues, the tendency of the laser signal to, both, decrease or increase in comparison with the signal from normal urothelium, should be perceived as a sign towards the neoplasm. Numerical simulation reveals that such a double-analysis at a multiwavelength mode potentially may be used to provide diagnostic accuracy.

Photodiagnosis and photodynamic therapy. 2020 May 20 [Epub ahead of print]

Nina Kalyagina, Maxim Loshchenov, Marine Amouroux, Christian Daul, Boris Kudashev, Walter Blondel, Victor Loschenov

Prokhorov General Physics Institute of the Russian Academy of Sciences, Vavilov Str. 38, 119991, Russian Federation; National Research Nuclear University MEPhI, Kashirskoye shosse 31, 115409, Russian Federation. Electronic address: ., Prokhorov General Physics Institute of the Russian Academy of Sciences, Vavilov Str. 38, 119991, Russian Federation. Electronic address: ., Université de Lorraine, CNRS, CRAN UMR 7039, Vandoeuvre-Lès-Nancy, France. Electronic address: ., Université de Lorraine, CNRS, CRAN UMR 7039, Vandoeuvre-Lès-Nancy, France. Electronic address: ., N.N. Blokhin Russian Cancer Research Center RAMS, Kashirskoye Shosse 24, 115478, Moscow, Russian Federation. Electronic address: ., Université de Lorraine, CNRS, CRAN UMR 7039, Vandoeuvre-Lès-Nancy, France. Electronic address: ., Prokhorov General Physics Institute of the Russian Academy of Sciences, Vavilov Str. 38, 119991, Russian Federation; National Research Nuclear University MEPhI, Kashirskoye shosse 31, 115409, Russian Federation. Electronic address: .