ORIGINAL ARTICLE Comparison of elastic scattering spectroscopy with histology in ex vivo prostate glands: potential application for optically guided biopsy and directed treatment O. M. A’Amar & L. Liou & E. Rodriguez-Diaz & A. De las Morenas & I. J. Bigio Received: 24 April 2012 / Accepted: 4 December 2012 / Published online: 18 December 2012 # Springer-Verlag London 2012 Abstract The false-negative rate of ultrasound-guided sex- tant prostate biopsy has been estimated to be as high as 35 %. A significant percentage (10–35 %) of these prostate cancers diagnosed at a second or later attempt are high grade and, therefore, potentially lethal. We discuss the feasibility for performing optically guided biopsy using elastic scattering spectroscopy (ESS) to reduce sampling errors and improve sensitivity. ESS measurements were performed on 42 prostate glands ex vivo and correlated with standard histopathological assessment. Sliced glands were examined with wavelength ranges of 330–760 nm. The ESS portable system used a new fiber-optic probe with integrated cutting tool, designed specif- ically for ex vivo pathology applications. ESS spectra were grouped by diagnosis from standard histopathological proce- dure and then classified using linear support vector machine. Preliminary data are encouraging. ESS data showed strong spectral trends correlating with the histopathological assign- ments. The classification results showed a sensitivity of 0.83 and specificity of 0.87 for distinguishing dysplastic prostatic tissue from benign prostatic tissue. Similar results were obtained for distinguishing dysplastic prostatic tissue from prostatitis with a sensitivity and specificity of 0.80 and 0.88, respectively. The negative predictive values obtained with ESS are better than those obtained with transrectal ultrasound (TRUS)-guided core-needle biopsy. Keywords Optical spectroscopy . Cancer . Pathology . Prostate . Fiber-optic probe Introduction Prostate cancer is the most commonly diagnosed cancer among men in the USA and is the second cause of cancer- related death among this population. However, if prostate cancer is detected in its early stage, it can be effectively treated and cured. Digital rectal examination (DRE) and prostate- specific antigen (PSA) measurement are the methods used by clinicians in screening for prostate cancer. However, the ability of DRE to detect early-stage prostate cancer is limited. PSA is also not ideal because this enzyme can rise naturally in men as they age or in other benign prostate diseases such as prostatitis. PSA cannot distinguish prostate cancer from nor- mal growth or other benign conditions. The definitive diag- nostic method for prostate cancer currently relies on histopathology assessment following a transrectal ultrasound (TRUS)-guided core-needle biopsy. This procedure is promp- ted either by an elevated serum PSA level or a palpable nodule. The prostate biopsy also has limitations due to the biopsy procedure. Ultrasound imaging of prostate cancer is not sensitive enough to detect cancer but is used only to guide the needle to areas of the prostate. This means that all prostate biopsies typically 6–12 are not targeted but random and false- negative rates can be high. In a multicenter clinical trial [1], in which 6,630 men were screened with PSA and TRUS, an abnormality on TRUS defined as a hypoechoic region corresponded to prostate O. M. A ’Amar (*) : E. Rodriguez-Diaz : I. J. Bigio Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA e-mail: oaamar@bu.edu L. Liou Cambridge Health Alliance, Harvard Medical School, Cambridge, MA, USA L. Liou : A. De las Morenas Department of Pathology, Boston University Medical Center, Boston, MA, USA Lasers Med Sci (2013) 28:1323–1329 DOI 10.1007/s10103-012-1245-6