Endoscopic histological assessment of colonic polyps by using elastic scattering spectroscopy

Background: Elastic-scattering spectroscopy (ESS) can assess in vivo and in real-time the scattering and absorption properties of tissue related to underlying pathologies. Objectives: To evaluate the potential of ESS for differentiating neoplastic from non-neoplastic polyps during colonoscopy. Design: Pilot study, retrospective data analysis. Setting: Academic practice. Patients: A total of 83 patients undergoing screening/surveillance colonoscopy. Interventions: ESS spectra of 218 polyps (133 non-neoplastic, 85 neoplastic) were acquired during colonoscopy. Spectral data were correlated with the classification of biopsy samples by 3 GI pathologists. High-dimensional methods were used to design diagnostic algorithms. Main Outcome Measurements: Diagnostic performance of ESS. Results: Analysis of spectra from polyps of all sizes (N = 218) resulted in a sensitivity of 91.5%, specificity of 92.2%, and accuracy of 91.9% with a high-confidence rate of 90.4%. Restricting analysis to polyps smaller than 1 cm (n = 179) resulted in a sensitivity of 87.0%, specificity of 92.1%, and accuracy of 90.6% with a highconfidence rate of 89.3%. Analysis of polyps 5 mm or smaller (n = 157) resulted in a sensitivity of 86.8%, specificity of 91.2%, and accuracy of 90.1% with a high-confidence rate of 89.8%. Limitations: Sample size, retrospective validation used to obtain performance estimates. Conclusion: Results indicate that ESS permits accurate, real-time classification of polyps as neoplastic or nonneoplastic. ESS is a simple, low cost, clinically robust method with minimal impact on procedure flow, especially when integrated into standard endoscopic biopsy tools. Performance on polyps 5 mm or smaller indicates that ESS may, in theory, achieve Preservation and Incorporation of Valuable Endoscopic Innovations performance thresholds. ESS may one day prove to be a useful tool used in endoscopic screening and surveillance of colorectal cancer.