Diagnosis of pelvic lymph node metastasis in prostate cancer using single optical fiber probe

Elastic light single-scattering spectroscopy system (ELSSS) is a biomedical tool which is used for detection of cancerous tissues ex-vivo. ELSSS spectra depend primarily on the size of scatterers in the tissue and are not directly related to changes in the absorption which are caused by variations of the biological macromolecules. In the present study, we aimed to detect metastasis in the pelvic lymph node by using combination of Principal Components Analysis (PCA) and Linear Discriminant Analysis (LDA). Single-scattering spectra in the 450-750nm wavelength regions were obtained from the total of 83 reactive lymph node and 12 metastatic lymph node samples from 10 prostatic cancer patients. The ELSSS spectral data were compared against the "gold standard" histopathology results. Data analyses were done via using PCA, followed by LDA. Receiver Operating Characteristic (ROC) curve analysis was employed for differentiating performance. The classification based on discriminant score provided sensitivity of 100% and specificity of 96.4%, in differentiating non-metastatic (reactive) from metastatic pelvic lymph nodes, with a Positive Predictive Value (PPV) of 0.8, a Negative Predictive Value (NPV) of 0.99 and the area under the ROC curve (AUC) of 0.99, respectively. In this study, it was shown that ELSSS system can accurately distinguish reactive and metastatic pelvic lymph nodes of prostate cancer with high PPV and NPV. It can be concluded that diagnostic accuracy of ELSSS system allows detecting metastatic tissues during operation.