Differentiation of Cancerous Prostate tissue from Non-Cancerous Prostate tissue by using Elastic Light Single-Scattering Spectroscopy: A Feasibility Study

Elastic light single-scattering spectroscopy system with a single optical fiber probe was employed to differentiate cancerous prostate tissue from non-cancerous prostate tissue ex-vivo just after radical prostatectomy. First, ELSSS spectra were acquired from cancerous prostate tissue to define its spectral features. Then, spectra were acquired from normal prostate tissue to define difference in spectral features between the cancerous and normal prostate tissues. Of the total 66 tissue samples were evaluated from nine patients by ELSSS system. Comparing of histopathology results and ELSSS measurements revealed that sign of the spectral slopes of cancerous prostate tissue is negative and non-cancerous tissue is positive in the wavelength range from 450 to 750 nm. Based on the correlation between histopathology results and sign of the spectral slopes, ELSSS system differentiates cancerous prostate tissue from noncancerous with a sensitivity of 0.95 and a specificity of 0.94. Keywords—Diagnosis, prostatic neoplasm, prostatectomy, spectrum analysis I.INTRODUCTION ROSTATE cancer is the most common cancer among American men. It causes death of men more than any other type of cancer apart from lung cancer. In the European Union, estimated prostate cancer incidence is 237,800 and mortality is 85,200 in 2004 [1]. Early prostate cancer usually causes no symptoms. Often, it is diagnosed during the workup for an elevated prostatespecific antigen (PSA) noticed during a routine checkup. Locally advanced prostate cancer disease has a low-cure rate compared to organ confined disease. Biochemical composition of cancerous tissue is different than non-cancerous tissue. Therefore, reflectance and autofluorescence spectrum of cancerous tissue is different than non-cancerous tissues [2],[3]. Elastic light scattering spectroscopy has been used by several research groups for diagnostic proposes of cancerous tissues [4],[5]. Diagnosis of F. T. Denkçeken is with the Biomedical Optic Research Unit, Department of Biophysics, Faculty of Medicine, Akdeniz University, Antalya, Turkey (phone: 242-249-6160; e-mail: tubadenkceken@akdeniz.edu.tr). S. M. Canpolat is with the Biomedical Optic Research Unit, Department of Biophysics, Faculty of Medicine, Akdeniz University, Antalya, Turkey (email: canpolat@akdeniz.edu.tr). T. Đ. Başsorgun and M.A. Çiftçioğlu are Department of Pathology, Faculty of Medicine, Akdeniz University, Antalya, Turkey (e-mail: ciftcioglu@akdeniz.edu.tr). F. S. Yücel and M. Baykara are Department of Urology, Faculty of Medicine, Akdeniz University, Antalya, Turkey (e-mail: baykara@akdeniz.edu.tr). the tissues by spectroscopy is based on variation of either scattering or absorption properties of the tissues. In the application of the reflectance spectroscopy in diagnosis of pathologic tissues, light travel from a source to a detector within a tissue and detected light reflect absorption and scattering properties of the tissues. Extracting absorption and scattering coefficient of the tissues from the reflectance spectra is desirable for the diagnostic proposes. One way of minimizing of the tissue absorption on the reflectance spectra is using a single optical fiber optical probe for both delivery and detection of light to and from the tissue [6]. Most of the detected light is singly-scattered. Therefore, it is called elastic light single-scattering spectroscopy (ELSSS) and it is sensitive to size of scatters rather than absorption and scattering properties of tissues due to small optical path length of the detected photons [6],[7]. ELSSS system has been used for diagnosis of malignant skin lesions on human [8] and demarcation of brain tumors from surrounded normal brain tissue [9]. ELSSS system has been successfully used in demarcation of melanoma tissues from non-melanoma skin tissue on an animal model [10].