Electrical impedance spectroscopy of prostatic tissues

Abstract

Prostate cancer has a high rate of incidence in the United State with over 27,000 deaths attributed to the disease in 2006. The current screening methods of digital rectal examination (DRE) and prostatic specific antigen (PSA) monitoring are extremely sensitive to physiological changes in the prostate, however their specificity is limited leading to one in four patients biopsied having negative findings for cancer. Electrical impedance spectroscopy (EIS) of the prostate may provide a clinical tool for improving the ability to differentiate between malignant tissue and benign abnormalities in the prostate. We have collected freshly excised prostates from 13 men immediately following radical prostatectomy. The prostates were sectioned into 3 mm slices and EIS measurements were recorded from each of the slices using a bipolar configuration over the frequency range of 1 kHz to 1 MHz. The area probed was marked so that after tissue fixation and slide preparation, histological assessment could be correlated directly with the recorded EIS spectra. Here we present a statistical analysis of these measurements along with the methodology used for data collection. Significant differences were found between cancer tissue and other benign tissues within the prostate. Both the conductivity and permittivity of cancer is significantly lower (p<0.001) that that of other tissue types across the spectrum measured. Further, there are significant differences in the measured spectra of cancer and benign prostatic hyperplasia (BPH), which, like cancer, also increases PSA production. © Springer-Verlag 2007.