Endoscopic Raman spectroscopy enables objective diagnosis of dysplasia in Barrett's esophagus

Background Early detection and targeted endoscopic resection of Barrett's esophagus–associated high-grade dysplasia (HGD) can prevent progression to invasive esophageal malignancy. Raman spectroscopy, a highly sophisticated analytical technique, has been translated into an endoscopic tool to facilitate rapid, objective diagnosis of dysplasia in the esophagus. Objective To evaluate the ability of endoscopic Raman spectroscopy (ERS) to objectively detect esophageal HGD and adenocarcinoma. Design A total of 798 one-second spectra were measured from 673 ex vivo esophageal tissue samples, collected from patients with Barrett's esophagus by using a novel endoscopic Raman probe. Spectra were correlated with consensus histopathology. Multivariate analysis was used to evaluate the classification accuracy of ERS ex vivo. Setting Probe measurements were conducted in the laboratory. Tissue specimens were collected from the operating theatre and endoscopy unit. Patients Tissue from 62 patients was included in the study. Interventions Endoscopic biopsy/resection or esophagectomy was performed where indicated clinically. Main Outcome Measurement Diagnostic performance of ERS for detection of HGD and esophageal adenocarcinoma. Results ERS demonstrated a sensitivity of 86% and a specificity of 88% for detecting HGD and adenocarcinoma. The ability to grade dysplasia and differentiate intestinal metaplasia from nonintestinal metaplasia columnar-lined esophagus was also demonstrated. Diagnostic classification was based on objective measurement of the biochemical profile of different tissue types. The potential for combination ERS and narrow-band imaging was also demonstrated. Limitations Measurements were taken from ex vivo tissue. Conclusion ERS enables rapid, accurate, objective diagnosis of superficial esophageal disease (metaplasia, dysplasia, intramucosal cancer) in clinically applicable time scales.