E. Borisova (1), E. Pavlova(2), P. Troyanova(2), P. Pavlova(3), L. Avramov(1)
1) Institute of Electronics, Bulgarian Academy of Sciences, Sofia, Bulgaria
2) University Hospital “Queen Yoanna-ISUL”, Sofia, Bulgaria
3) Technical University – Sofia, branch Plovdiv, Bulgaria
Light-induced autofluorescence spectroscopy (LIAFS) is very attractive tool for early diagnosis of cancer due to its high sensitivity, easy-to-use methodology for measurements, lack of need for contrast agents application on the tissue under investigation, possibilities for real time measurements and noninvasive tumor detection. Diffuse reflectance spectroscopy (DRS) is very promising for pigmented skin lesions and reveal high sensitivity for malignant melanoma diagnosis. Nevertheless of all these excellent features of the autofluorescence and reflectance spectroscopy techniques, till our days, no reliable and universal system for spectral detection of skin cancer has not appeared on the medical market.
Problems for development of such diagnostic fluorescence system for skin cancer detection are related to the great variety of benign and malignant forms of skin pathologies, for example basal cell carcinoma lesions have more than 15 sub-types, squamous cell carcinoma lesions, have about 10 different subtypes, and all of them have variety of benign and dysplastic forms, as well as they are different, including by their fluorescence properties, on different stages on the lesion growth. Good point here is the fact that we could use LIAFS and DRS for evaluation of the lesion stage, bad point is that we will need to compare this exact situation with great variety of other possibilities, such as lesion kind, stage of growth, and even patient skin general conditions, such as influence of medicines, ages, cutaneous phototype, etc.
Our investigation is a part of a clinical trial for introduction of spectral diagnostic system for skin cancer detection in the common practice of the dermatological departments in our hospital. Autofluorescence and reflectance spectroscopy are applied to several different classes of malignant non-melanoma cutaneous lesions. Initially, they were classified visually and dermatoscopically. Second step was detection of lesion’ and surrounding normal skin using different excitation wavelengths, namely 365, 385, and 405 nm for autofluorescence and broad band light irradiation at 400-900 nm for the reflectance spectroscopy. In the end for every lesion histological examination is used as a “gold standard” for all our investigations.
The spectra and dermatoscopic evaluations were obtained from more than 350 patients up to now. Spectral properties of variety of benign cutaneous lesions are also evaluated for development of more precise discrimination algorithms for diagnosis of cancer lesions. The origins of diagnostically significant spectral features are evaluated and differentiation schemes will be discussed in our report.
Clinical trial is currently under implementation and with broadening of the database with fluorescence spectra of major skin benign and malignant pathologies we expect to receive objective tool for detection and evaluation of skin lesion type, which could become a basis for reliable system for fluorescence detection of non-melanoma skin cancer.
Dr. Ekaterina Georgieva Borisova
Institute of Electronics, Bulgarian Academy of Sciences, Associate Professor
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