Background: Recent technological advances have stimulated the development of endoscopic optical biopsy technologies. This study compared the accuracy of endoscopic diagnosis using magnifying narrow-band imaging (NBI) and histologic diagnosis of esophageal squamous lesions.
Methods: Patients at high risk for esophageal squamous cell carcinoma were examined with endoscopy and subsequent biopsy. The lesions diagnosed as cancer on NBI and the lesions diagnosed as cancer on biopsy were resected endoscopically or surgically. Histological diagnoses of resected specimens, the reference standards in this study, were made by a pathologist who was blind to both the endoscopic and biopsy diagnoses. The primary outcome was the accuracy of endoscopic and biopsy diagnosis. A noninferiority trial design with a noninferiority margin of -10% was chosen to investigate the accuracy of endoscopic diagnosis using magnifying NBI.
Results: Between November 2010 and October 2012, a total of 111 lesions in 85 patients were included in the analysis. The accuracy of endoscopic diagnosis and biopsy diagnosis for all lesions was 91.0% (101/111) and 85.6% (95/111), respectively. The difference in diagnostic accuracy was 5.4% (95% confidence interval: -2.9%-13.7%). The accuracy of endoscopic diagnosis and biopsy diagnosis of invasive cancers was 94.9% (74/78) and 84.6% (66/78), respectively. The difference was 10.3% (95% confidence interval: 1.6%-19.0%) for invasive cancers. The lower bound of the 95% confidence interval was above the prestated -10% in both cases.
Conclusion: Noninferiority of endoscopic diagnosis by magnifying NBI to histologic diagnosis by biopsy was established in this study (p = 0.0001).
Trial registration: The study was registered on 9th November 2010 in the University Hospital Medical Network Clinical Trials Registry as number: UMIN000004529.