Comparison Trial between I-SCAN-Optical Enhancement and Chromoendoscopy for Evaluating the Horizontal Margins of Gastric Epithelial Neoplasms

Abstract

Background/aims: Endoscopic submucosal dissection is a widely used treatment for gastric epithelial neoplasms. Accurate delineation of the horizontal margins is necessary for the complete resection of gastric epithelial neoplasms. Recently, image-enhanced endoscopy has been used to evaluate horizontal margins of gastric epithelial neoplasms. The aim of this study was to investigate whether I-SCAN-optical enhancement (I-SCAN-OE) is superior to chromoendoscopy in evaluating the horizontal margin of gastric epithelial neoplasms.

Methods: This was a multicenter, prospective, and randomized trial. The participants were divided into two groups: I-SCAN-OE and chromoendoscopy. For both groups, we first evaluated the horizontal margins of early gastric cancer or high-grade dysplasia using white-light imaging, and then evaluated, the horizontal margins using I-SCAN-OE or chromoendoscopy. We devised a unique scoring method based on the pathological results obtained after endoscopic submucosal dissection to accurately evaluate the horizontal margins of gastric epithelial neoplasms. The delineation scores of both groups were compared, as were the ratios of positive/negative horizontal margins.

Results: In total, 124 patients were evaluated for gastric epithelial neoplasms, of whom 112 were enrolled in the study. A total of 112 patients participated in the study, and 56 were assigned to each group (1:1). There was no statistically significant difference in the delineation scores between the groups (chromoendoscopy, 7.80±1.94; I-SCAN-OE, 8.23±2.24; p=0.342).

Conclusions: I-SCAN-OE did not show superiority over chromoendoscopy in delineating horizontal margins of gastric epithelial neoplasms.

Keywords: Chromoendoscopy; Endoscopic submucosal dissection; Gastric cancer; Gastric neoplasm; Image-enhanced endoscopy.

Fig. 1

Chromoendoscopy versus I-SCAN-optical enhancement (OE). (A) Before chromoendoscopy. (B) After chromoendoscopy. (C) Before I-SCAN OE. (D) After I-SCAN OE.

Fig. 2

Distance from the margin of neoplasm. (A) A 5-mm length of the thick tip of the dual knife as a scale. (B, C) Dots were placed each at 5 mm from the margin using the thick tip of the dual knife.

Fig. 3

(A) After the dots were placed each 5 mm from the horizontal margin the tumor was resected. (B) Gross findings of the resected specimens.

Fig. 4

Microscopic findings of the specimen. The margins of the resected specimen were marked on the lateral and vertical sides with different colors and sectioned perpendicularly at 2-mm intervals to examine the exact margin and the distance from the safety margin. Pathological evaluation measured the length of the nearest resection margin with a pen on the H&E-stained slide at the cancerous lesion (×1).

Fig. 5

Delineation scoring system. Scores from 0 to 12 were evaluated as the sum of the scores for each of the four margins, which was termed the delineation score. Score 3, excellent (lateral margin ≥4 mm, ≤6 mm); score 2, good (lateral margin ≥2 mm, <4 mm or >6 mm, ≤8 mm); score 1, fair (>0 mm, <2 mm or >8 mm, ≤10 mm); score 0, poor (lateral margin positive or >10 mm).

Fig. 6

Flowchart showing participant enrollment, randomization and inclusion in the analysis. I-SCAN-OE, I-SCAN-optical enhancement.