A pilot study for the real-time detection of colorectal cancer using electrical impedance spectroscopy

Colorectal cancer is the fourth most common cancer worldwide, with a lifetime risk of around 20%. Current technology available at endoscopy and peri-operatively do not allow the clinician to provide an indication of the likelihood of malignancy. There is, therefore, a need for novel diagnostic techniques to detect malignant lesions at an early stage. Given the new developments in minimally invasive diagnostics and management strategies, real-time point-of-care technology represents a potential area for further research into improving diagnosis and influencing management of colorectal cancer. Electrical impedance spectroscopy (EIS) has been shown to accurately discriminate malignant lesions in other cancers. We present a feasibility study for the real-time detection of malignant colorectal tissue using EIS. This prospective ex-vivo pilot study used a Zedscan device to obtain EIS measurements from excised human colorectal tumour tissue and matched normal colonic mucosa in 22 freshly resected specimens following elective surgery for colorectal cancer. Histopathological examination was used to confirm the final diagnosis. Statistical significance was assessed with the Wilcoxon signed rank test. Twenty-two colorectal resection specimens were tested with EIS. Three were excluded as final histopathology did not identify colorectal adenocarcinoma. EIS was able to discriminate cancer with statistically significant results when applying frequencies over 152KHz (p < 0.05). At a cut-off level of 350 Ω, the area under the receiver operating characteristic curve was 0.7097. This preliminary study demonstrates that EIS changes in colorectal tissue are detectable and statistically significant, suggesting that EIS has the potential as a novel non-invasive point of care test for detecting colorectal cancer.