Confocal laser endomicroscopy for upper gastrointestinal neoplasia: Systematic review and meta-analysis

Probe-based confocal laser endomicroscopy (pCLE) enables real-time, in vivo microscopic evaluation of upper gastrointestinal mucosa. Although many studies have evaluated its diagnostic performance, comprehensive synthesis of its accuracy, safety, and clinical utility remains limited.

We performed a systematic review and meta-analysis of studies assessing diagnostic accuracy, safety, and clinical utility of pCLE for detecting dysplasia or neoplasia in the upper gastrointestinal tract. MEDLINE, Embase, and the Cochrane Library were searched from inception to October 2024 for studies comparing pCLE with histopathology. Study quality was assessed using QUADAS-2. Pooled sensitivity and specificity were estimated using a bivariate random-effects model. Safety outcomes and clinical impact were narratively summarized.

Thirty-three studies (n = 2,350 patients) were included: 15 focused on esophageal, 16 on gastric, and two on mixed upper gastrointestinal lesions. For esophageal neoplasia, pooled sensitivity was 0.89 (95% confidence interval [CI] 0.84-0.92) and specificity was 0.79 (95% CI 0.68-0.87). For gastric neoplasia, pooled sensitivity was 0.89 (95% CI 0.83-0.93) and specificity was 0.95 (95% CI 0.92-0.96). In selected clinical settings, such as Barrett's esophagus with subtle mucosal and no discrete macroscopic lesions, adjunctive pCLE altered real-time therapeutic management in up to 69.2% of cases (9/13). Only minor adverse events, such as transient bleeding or fluorescein-related reactions, were reported.

pCLE is a safe and accurate adjunct to standard upper gastrointestinal endoscopy, particularly when lesion conspicuity is low or histologic confirmation is important. However, pooled estimates, particularly the high specificity for gastric lesions, should be interpreted cautiously due to potential small-study effects.