Optical biopsy for esophageal squamous cell neoplasia by using endocytoscopy

Abstract

Background: Endocytoscopy (ECS) enables microscopic observation in vivo for the gastrointestinal mucosa; however, there has been no prospective study in which the diagnostic accuracy of ECS for lesions that have not yet undergone histological diagnosis was evaluated. We conducted a surveillance study for patients in a high-risk group of esophageal squamous cell carcinoma (ESCC) and evaluated the in vivo histological diagnostic accuracy of ECS.

Methods: This study was a multicenter prospective study. We enrolled 197 patients in the study between September 1, 2019 and November 30, 2020. The patients first underwent white light imaging and narrow band imaging, and ultra-high magnifying observation was performed if there was a lesion suspected to be an esophageal tumor. Endoscopic submucosal dissection (ESD) was later performed for lesions that were diagnosed to be ESCC by ECS without biopsy. We evaluated the diagnostic accuracy of ECS for esophageal tumorous lesions.

Results: ESD was performed for 37 patients (41 lesions) who were diagnosed as having ESCC by ECS, and all of them were histopathologically diagnosed as having ESCC. The sensitivity [95% confidence interval (CI)] was 97.6% (87.7-99.7%), specificity (95% CI) was 100% (92.7-100%), diagnostic accuracy (95% CI) was 98.9% (94.0-99.8%), positive predictive value (PPV) (95% CI) was 100% (91.4-100%) and negative predictive value (NPV) (95% CI) was 98.0% (89.5-99.7%).

Conclusions: ECS has a high diagnostic accuracy and there were no false positives in cases diagnosed and resected as ESCC. Optical biopsy by using ECS for esophageal lesions that are suspected to be tumorous is considered to be sufficient in clinical practice.

Keywords: Diagnostic accuracy; Endocytoscopy; Esophageal cancer; Intraepithelial neoplasia; Optical biopsy.

Fig. 1

Esophageal EC classification. a EC1a (normal) shows regularly arranged large rhomboid-shaped cells. b EC1b (esophagitis) shows blunted edges and more rounded cells. c EC2 (intraepithelial neoplasia) shows an increase in cellular density but still with a recognizable cell structure. d EC3 (squamous cell carcinoma) shows complete loss of cellular structure with a significant increase in cellular density

Fig. 2

Flow chart showing diagnoses of the 197 lesions by using white-light imaging endoscopic, magnifying endoscopy combined with narrow-band imaging and ultra-high magnifying endoscopy. ESD, endoscopic submucosal dissection; WLI white-light imaging, NBI narrow-band imaging

Fig. 3

A representative case of SCC in EC3: A Endoscopic view by WLI. Redness and a slightly depressed lesion (yellow arrows) can be seen. B Endoscopic view by NBI. A brownish area with background coloration (white arrows) can be seen. C Endocytoscopic image of the lesion. EC classification was graded to be 3 by the endoscopist. D The resected specimen histologically revealed SCC (red line). E Photomicrograph of the resected specimen shows carcinoma in situ (H&E, orig. mag. × 40). SCC, squamous cell carcinoma; EC3 EC classification 3, WLI white-light imaging, NBI barrow-band imaging

Fig. 4

A representative case of intraepithelial neoplasia: A Endoscopic view by WLI. A faintly reddish lesion (yellow arrows can be seen. B Endoscopic view by NBI. A brownish area without background coloration (white arrows) can be seen. C Endocytoscopic image of the lesion. EC classification was graded to be 2 by the endoscopist. D Photomicrograph of the biopsied specimen shows atypical cells (H&E, orig. mag. × 40). EC2 EC classification 2, WLI white-light imaging, NBI narrow-band imaging