Pilot study on confocal endomicroscopy for determination of the depth of squamous cell esophageal cancer in vivo

Background and Aim: Confocal endomicroscopy is ultra-high-magnification endoscopy with histological observation during ongoing endoscopy. We planned a pilot study of the diagnosis of the depth of esophageal cancer using confocal endomicroscopy for treatment strategies. Methods: Patients had 14 superficial esophageal cancers and one dysplasia. The depth of neoplasms in 15 lesions was confirmed by endoscopic mucosal resection or surgery. We examined the rate of delineation and compared results of confocal imaging with histological findings. We classified two cellular and three microvascular patterns on confocal endomicroscopic images: CP-N for normal squamous mucosa and CP-Ca for cancerous lesion; VP-type A for normal squamous mucosa; VP-type B for T1a-EP and T1a-LPM cancers; and VP-type C for T1a-MM or a more invasive cancer pattern. We measured diameters of microvessels for the three patterns of confocal endomicroscopic images and histological specimens. Results: The rate of delineation was 73.3% (11/15) for esophageal cancer. The results of confocal imaging coincided well with microvessel distribution on horizontal histology. Two endoscopists blindly diagnosed the two types by cellular pattern and the three types by vascular pattern: their overall accuracies were 96% and 89% for the cellular pattern and 85% and 85% for the vascular pattern, respectively. The k value of the cellular pattern and the vascular pattern diagnosis was 0.84 and 0.75, respectively. Conclusion: Scoring and quantification of confocal endomicroscopic images may be useful for the differential diagnosis and diagnosis of superficial invasion by squamous cell carcinoma.