Invivo diagnosis of early-stage gastric cancer found after Helicobacter pylori eradication using probe-based confocal laser endomicroscopy.

Abstract

Early-stage gastric cancer (EGC) found after Helicobacter pylori (Hp) eradication often displays non-tumorous regenerative epithelium and/or maturated tumorous epithelium overlying the cancerous tissue, which may confuse endoscopic and histological diagnosis. Probe-based confocal laser endomicroscopy (pCLE) enables invivo real-time optical biopsy. We compared the diagnostic yields for these EGC cases using conventional white light endoscopy (WL), magnifying endoscopy with narrow-band imaging (ME-NBI), pCLE, and endoscopic biopsy; we also compared the accuracy of the horizontal extent diagnosis between ME-NBI and pCLE. This study enrolled 30 patients with 36 EGC lesions after successful Hp eradication. Diagnostic yields of WL, ME-NBI, pCLE, and endoscopic biopsy were prospectively compared. Four points of cancerous margins (oral, anal, anterior, and posterior sites) were also prospectively evaluated with M-NBI and pCLE to determine the horizontal extent of the EGC. Diagnostic yield was significantly higher with pCLE than with WL and endoscopic biopsy (97 vs 72%, 97 vs 72%, P=0.0159, 0.0077, respectively), whereas it did not differ from ME-NBI (88.9%, P=0.371). Height of non-tumorous regenerative epithelium or maturated atypical glands was 104.7±34.2μm in the pCLE-positive cases, whereas it was 188.3±27.1μm in a pCLE-negative case (P=0.0004). Diagnostic accuracy of the horizontal margin of EGC was significantly higher with pCLE than with ME-NBI (92 vs 70%, P=0.0159). pCLE may be helpful for the diagnosis of ambiguous ECG found after Hp eradication because it enables real-time scanning throughout the lesion and detection of subsurface microstructure.