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10A MULTIMODAL APPROACH TO NON-INVASIVE DIAGNOSIS OF BASAL CELL CARCINOMA:
A PILOT STUDY
ELINA GENINA1'2, YANA KUZINOVA3, YURY SURKOV12, ISABELLA SEREBRYAKOVA12, EKATERINA LAZAREVA1'2, OLGA KONOPATSKOVA3, ALI ANSARY4, VALERY TUCHIN1,2,5
1Optics and Biophotonics Department, Saratov State University, Saratov, Russia 2Laboratory of laser molecular imaging and machine learning, Tomsk State University, Tomsk, Russia 3Department of Faculty Surgery, Saratov State Medical University, Saratov, Russia 4Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, Iran 5Laboratory of Laser Diagnostics of Technical and Living Systems, Institute of Precision Mechanics and Control, FRC "Saratov Scientific Centre "of the Russian Academy of Sciences, Saratov, Russia [email protected]
ABSTRACT
Despite the development of medicine, cancer remains one of the most dangerous diseases nowadays. The detection and treatment of cancer is one of the most challenges for medicine in the twenty-first century. An effective solution of the problem is the use of modern interdisciplinary technologies. Most often, if the tumor is diagnosed earlier and treated, the patient will have a better prognosis and much greater opportunities for complete recovery. Many recent technological innovations have used physics principles, such as optics and coherent photonics, to improve early diagnostic and therapeutic procedures to reduce cancer incidence and mortality [1]. In this study, the development of technologies for biomedical imaging of skin cancer is presented.
Skin cancers are due to the development of abnormal cells that have the ability to invade or spread to other parts of the body. There are three main types of skin cancers: basal-cell carcinoma (BCC), squamous-cell carcinoma (SCC), and melanoma. BCC is the most common epithelial neoplasms of the skin, accounting for 45-90% of all malignant epithelial tumors of this localization [2]. BCC consists of cells similar to the cells of the basal layer of the epidermis. It differs from other skin cancers by extremely rare metastasis, but it is capable of extensive local growth, which leads to significant cosmetic and functional disorders [3].
In this pilot study, a combination of high-resolution ultrasound examination and optical methods (Raman spectroscopy, optical coherence tomography (OCT), and diffuse reflectance spectroscopy) were used.
The study involved light-skinned volunteers with basal cell carcinoma and benign neoplasms and volunteers with high pigmented health skin. Informed consents were acquired from all patients prior to the study. Enrolled patients' age ranged from 48 to 78 years. Enrolled patients were 2 Caucasian males and 7 females. Differentiation of neoplasms was carried out using morphological research: basal cell carcinoma (7 lesions) and benign neoplasms (2 lesions).
Ultrasound DUB SkinScanner (tpm taberna pro medicum GmbH, Germany) was used in the initial management of neoplasms (including helping in the differential diagnosis and measurement of thickness). High resolution ultrasound imaging systems enabled ultrasound to differentiate structures of less than 100 microns on the beam axis (axial resolution) and 200 microns on the scan axis (resolution axis). The frequency ranges 33 and 75 MHz, allowed visualisation of the superficial layer of the skin (epidermis and dermis, and the upper part of hypodermis), where the majority of lesions and skin tumors were located. Figures 1 show photography of the superficial BCC from smartphone and dermascope, and ultrasonic images with different resolutions.
(c)
Figure 1: Photography of the superficial BCC from (a) smartphone and (b) dermascope, and (c) ultrasonic images with different
resolutions.
It is well seen the borders of the tumors. Real sizes were evaluated. For example, for the superficial BCC the depth was evaluated from 0.45 to 0.74 mm in different sites, for pigmented BCC it was from 0.2 to 0.71 mm, and for pigmented benign neoplasm it was about 2.22 mm.
Neoplastic cells are characterized by increased nuclear material, an increased nuclear-to-cytoplasmic ratio, increased mitotic activity, abnormal chromatin distribution, and decreased differentiation. There is a progressive loss of cell maturation, and proliferation of these undifferentiated cells results in increased metabolic activity. General features of neoplastic cells result in specific changes in nucleic acid, protein, lipid, and carbohydrate quantities and/or conformations. For the study we used Raman spectrometer QE65000 (Ocean Optics, USA) with diode laser 785 nm (Ocean Optics, USA) and probe.
The original analyses for Raman signals are based on differences in intensity, shape, and location of the various Raman bands between normal and cancerous cells and tissues. However, there are no distinctive Raman peaks or bands that can be uniquely assigned to BCC by visual inspection alone. The development of the malignant skin disease increases the content of metabolic products in the pathological areas of the skin, changes the concentration of proteins and lipids. Proteins predominantly contributes to the appearance of bands in the spectral range 1240-1270, 1340, 1440-1460, and 1665 cm-1, the spectral features arising from the contribution of lipids, are observed in the 1271-1301, 1440, 1650-1660 cm-1 bands. One of the significant differences between malignant and benign formations is the process of metabolism and destruction of collagen. Cells of malignant tumors form fast-growing, low-differentiated structures, and the development of such structures is accompanied by the increased activity of collagenase. Collagenase destroys the molecular bonds of collagen fibers, and changes in Raman spectra of skin tissue can be observed in 1248, 1454, and 1665 cm-1 bands associated with peaks of collagen [4].
In the BCC, there was an increased content of proteins (430, 475) and nucleic acids (622, 685), a decreased content of lipids (1287, 1419) and keratin (1463, 1670). Increased peaks associated with DNA (755) and cell nuclei (831). Optical coherence tomography is used for preoperative determination of the peripheral boundaries of BCC in order to choose the optimal treatment method and minimize the invasiveness of surgical intervention. OCT is characterized by high efficiency for the in vivo diagnosis of malignant and benign skin tumors. OCT B-scans were obtained using the GAN930V2-BU spectral OCT (Thorlabs, USA) operating at a central wavelength of 930 nm with axial and lateral resolutions of 6.00 and 7.32 ^m, respectively, and a scanning depth of 2 mm. OCT was used for in vivo differential diagnosis between benign skin neoplasms and BCC. It was well seen different heterogeneity of skin structures. We used aqueous 70%-glycerol solution for increasing the probing depth of OCT. Enhancers of epidermis permeability was not used because the epidermal barrier was injured and not prevented diffusion of OCA and water. It was well seen that after 10 minutes the optical probing depth increased in 1.5-2 times and visualization of heterogeneities characteristic of basal cell carcinoma has been improved (fig. 2).
(a) (b)
Figure 2: OCT-scans of skin with BCC (a) before optical clearing and (b) in 10 min after 70%-glycerol application.
Diffuse backscattered spectroscopy is well suited for use in biomedical applications due to its low instrumentation cost and easy implementation. Reflectance measurement is a function of optical scattering and absorption. The primary sources of scattering in skin include collagen, mitochondria, melanin, and cell nuclei. Hemoglobin and melanin are the primary sources of absorption in skin. Diffuse reflectance was measured in the range of 400 - 2150 nm using both USB4000-UV-VIS and NIRQUEST spectrometers (Ocean Optics, USA) equipped with QR400-7-VIS-NIR fiber optic probes (Ocean Optics, USA). Determined by visual inspection, BCC contributed to reflectance spectral intensity and spectral slope. It was founded that areas of the skin most affected by basal cell carcinoma had lower reflectance intensities compared with normal skin.
Thus, the sizes of neoplasms were evaluated using ultrasound examination, and their internal structure was visualized using OCT in combination with optical clearing. Diffuse reflectance extracted physiological parameters such as hemoglobin content, oxygen saturation, and tissue microarchitecture. Raman spectroscopy was helpful for determining
lipid, nuclear, and protein content. Our results demonstrated the ability of these modalities to quantitatively assess tissue biochemical, structural, and physiological parameters that could be used to determine tissue pathology.
The study was funded by RFBR, project number 20-52-56005, and the grant under the Degree of the Government of the Russian Federation No. 220 of 09 April 2010 (Agreement No. 075-15-2021-615 of 04 June 2021).
REFERENCES
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[2] MedElement. Clinical protocols. Skin Cancer. https://diseases. medelement.com/disease/paK-KO>KH-2018/16198, 2021.
[3] G. Paolino, M. Donati, D. Didona, S.R. Mercuri, C. Cantisani, Histology of Non-Melanoma Skin Cancers: An Update, Biomedicines, 71, 2017.
[4] I.A. Bratchenko, L.A. Bratchenko, A.A. Moryatov, Yu.A. Khristoforova, D.N. Artemyev, O.O. Myakinin, A.E. Orlov, S.V. Kozlov, V.P. Zakharov, In vivo diagnosis of skin cancer with a portable Raman spectroscopic device, Experimental Dermatology, 652-663. 2021.
