Image-enhanced, Chromo, and Cap-assisted Colonoscopy for Improving Adenoma/neoplasia Detection Rate: a Systematic Review and Meta-analysis

Objective: The effectiveness of narrow band imaging (NBI), chromoendoscopy (CE), and cap-assisted colonoscopy (CAC) on adenoma detection rate (ADR) has been investigated in previous meta-analyses; however, there have been no meta-analyses of autofluorescence imaging (AFI) or flexible spectral imaging color enhancement (FICE) or i-scan. The aim of this study was to determine whether AFI and FICE/i-scan was more effective than standard/high-definition white light endoscopy to improve ADR and to update previous meta-analyses of NBI, CE, and CAC.

Design: A systematic review and meta-analysis was conducted. Four investigators selected appropriate randomized controlled trials (RCT) using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guideline. All RCTs in which colonoscopy were performed with AFI, FICE, i-scan, NBI, CE, and CAC were included. The risk ratios (RRs) calculated from adenoma/neoplasia detection rate were used as the main outcome measurement.

Results: A total of 42 studies were included in the analysis. Pooled estimates of RR (95%confidence interval [CI]) using AFI, FICE/i-scan, NBI, CE, and CAC were 1.04 (95% CI: 0.87-1.24) (I² = 0%) (fixed effects model [FEM]); 1.09 (95% CI: 0.97-1.23) (I² = 5%) (FEM); 1.03 (95% CI: 0.96-1.11) (I² = 0%) (FEM); 1.36 (95% CI: 1.23-1.51) (I² = 16%) (FEM); and 1.03 (95% CI: 0.93-1.14) (I² = 48%) (random effects model [REM]), respectively. The pooled estimate of RR (95%CI) using indigo carmine in non-ulcerative colitis (UC) patients and methylene blue in UC patients was 1.33 (95% CI: 1.20-1.48) (I² = 14%) (FEM) and 2.39 (95% CI: 1.18-4.84) (I² = 0%) (FEM), respectively.

Conclusion: In contrast to AFI, FICE/i-scan, NBI, and CAC, only CE improves ADR. CE with methylene blue, though not NBI, is effective for surveillance of neoplasia in chronic UC patients.