Confocal laser endomicroscopy for in vivo diagnosis of early squamous cell carcinoma in the esophagus

Background & Aims: Confocal laser endomicroscopy has been shown to allow direct histologic imaging of gastrointestinal tumors in vivo. This study was designed to assess the potential of endomicroscopy for predicting histology in vivo during routine endoscopy in patients with early squamous cell cancer. Methods: Twenty-one consecutive patients with suspected early squamous cell cancer who had been referred for endoscopic therapy to a tertiary-care academic medical center were included in this prospective study. After staining with 0.5% Lugol's solution and injection of 500 mg fluorescein sodium, unstained mucosal areas were examined using confocal imaging. Images of each scanned lesion were acquired and stored digitally, and in vivo diagnosis was performed during ongoing endoscopy. Biopsy specimens were taken from every lesion. The confocal images were reviewed by 2 endoscopists, who were blinded to the histology and endoscopic appearance. Results: Confocal images were acquired from 43 lesions in 21 patients. Twenty-seven of the 43 lesions (63%) were proven to be squamous cell cancer on histology. All squamous cell cancers were diagnosed correctly by endomicroscopy and 2 lesions were falsely diagnosed as neoplastic. The overall accuracy was 95%, and the sensitivity and specificity were 100% and 87%, respectively. Intraobserver agreement was almost perfect (kappa = 0.95) and interobserver agreement was substantial (kappa = 0.79). Conclusions: Confocal laser endomicroscopy is able to provide virtual histology of early squamous cell cancers with a high degree of accuracy and can facilitate rapid diagnosis during routine endoscopy.