Sa1503 Comparison of Image-Enhancing Modalities for the Detection of Colonic Adenomas: a Systematic Review and Network Meta-Analysis

Comparison of Image-Enhancing Modalities for the Detection of Colonic Adenomas: a Systematic Review and Network MetaAnalysis Ahmad S. Alawad*, Susan Hutfless, Venkata S. Akshintala, Vikesh K. Singh, Mehak Idrees, Ayesha Kamal, Payal Saxena, Izzah Vasim, Charles J. Kahi, Shabana F. Pasha, Mouen Khashab Johns Hopkins Medical Institute, Baltimore, MD; Medicine, Medstar Franklin Square Medical Center, Baltimore, MD; Medicine, Indiana University-Purdue University Indianapolis, Indianapolis, IN; Gastroenterology, Mayo Clinic Arizona, Scottsdale, AZ Background: Colonoscopy is the gold standard for the detection of premalignant adenomatous colonic lesions. However, up to 25% of adenomas are missed during colonoscopy. Novel endoscopic imaging techniques have been developed to improve detection of colonic adenomas. AIM To perform a systematic review (SR) and network meta-analysis (NMA) of RCTs that compared at least two different imaging modalities in patients undergoing screening, surveillance or diagnostic colonoscopies. The goal of the NMA was to identify priority comparisons for future trials. Methods: The MEDLINE, EMBASE and Cochrane Library databases were searched for RCTs that compared imaging modalities. For inclusion in the NMA, the number of patients with at least one adenoma detected by imaging modality group needed to be reported.Non-randomized studies and trials including patients with IBD, familial adenopolyposis syndrome, hyperpolyposis syndrome or HNPCC were excluded. The modalities of interest were: standard definition white light (SD-WLE), high definition white light (HDWLE), narrow band imaging (NBI), autofluorescence imaging (AFI), I-scan, Fuji intelligent color enhancement (FICE) and dye-based chromoendoscopy. Adenoma detection (AD) comparisons were analyzed using a Bayesian NMA with a random effects model. The yields of the imaging modalities were compared using odds ratios (OR) (higher OR indicated higher AD).To identify the best performing imaging modality, we ranked OR from 100,000 simulations of the data and considered the modality that ranked as one of the top 3 in most cases as the best at AD, and the highest priority for future trials. Results 24 RCTs (patients 11,576) met the inclusion criteria. At least one study that compared each imaging modality of interest was identified. HD-WLE was used as the common comparator (Figure 1). I-scan ranked as one of the top 3 best performing modalities in over 90% of simulations, followed by FICE (Figure 2). The OR comparing I-scan to the other modalities ranged from 1.24 (95% CI 0.72 2.35; compared with FICE) to 2.44 (95% CI 1.4 4.04; compared with SD-WLE). SD-WLE ranked in the top 3 in 1% of simulations. The quality of trials was graded moderate because the outcome assessors were not blinded to the colonoscope modality used and the funding source was often a company that produced one of the technologies being compared. Conclusion: This SR and NMA shows that SD-WLE is outperformed by all other imaging modalities. The findings suggest that I-scan and FICE are the highest priority modalities for future trials, but the magnitude of the AD effect may not be as extreme because of the small number of RCTs using I-scan and FICE that met our inclusion criteria. Head to head trials of imaging modalities are unlikely to have blinded outcome assessors, but trials performed independent of industry sponsorship are possible. Sa1504 Diagnostic Yield of High-Definition Colonoscopy Versus Standard-Definition Colonoscopy for the Detection of Colonic Polyps: a Meta-Analysis of Randomized Controlled Trials Jennifer L. Horsley-Silva*, Saowanee Ngamruengphong, Michele D. Lewis Internal Medicine, Mayo Clinic Jacksonville Florida, Jacksonville, FL; Gastroenterology, Mayo Clinic Jacksonville Florida, Jacksonville, FL Background: The high-definition (HD) resolution of colonoscopes has increased over the last few years. Studies have shown conflicting data regarding HD colonoscopy and increased polyp detection rate as well as adenoma detection rate over standard-definition colonoscopy (SVE). Objective: We conducted a meta-analysis to compare the diagnostic yield of HD colonoscopy with SVE for detection of colorectal polyps and detection of colorectal adenomas. Methods: Literature searches were performed in Ovid Medline, EMBASE, and Cochrane databases for randomized controlled trials comparing HD and SVE from the earliest available online year of indexing up to November 2012. In addition, abstracts from major relevant international conferences (AGA, ACG and ASGE) published from 2010 to 2012 were also searched manually. Outcome measures included the proportion of patients with any polyp, adenoma, advanced adenoma, and mean difference of adenoma per patient detected. Data on yield of both modalities were extracted, pooled, and analyzed to estimate weighted incremental yield (IY, yield of HD yield of SVE) and 95% confidence intervals (95% CI) of HD over SVE using a fixed effect model. A random effects model was used for analyses with heterogeneity. Results: From 346 citations, 5 randomized controlled clinical trials were identified consisting of 1,834 subjects. Mean age of subjects was 60.9 years old and 53.6% were male. Meta-analysis revealed that there was no significant IY with HD over SVE for detection of any polyp (IY 4%; 95% CI, -1% to 19%; 4 studies, n 1,414), adenoma (IY 3%; 95% CI, -1% to 8%; 4 studies, n 1664), and high-risk adenoma (IY 1%; 95% CI, -1% to 4%; 3 studies, n 1274). There was no significant heterogeneity among studies and fixed effect model was used in all analysis. When analyzed as the mean number of adenomas detected per patient, the pooled weighted mean difference in the number of adenomas detected was not different between HD and SVE [mean difference 0.03 (95% CI -0.14 to 0.21; p 0.7; fixed effect model; 3 studies, 1244 patients]. The pooled weighted mean difference in number of small adenomas ( 5mm) detected per patient was significantly higher in HD group [mean difference 0.11 (95% CI 0.01 to 0.21; p 0.03; fixed effect model; 2 studies, 1010 patients]. Conclusion: This meta-analysis suggests that HD colonoscopy improves the detection of small adenomas. Whether increased detection of small adenomas has any impact on clinical outcomes is unclear. Further studies are needed to evaluate the impact of this technology on longterm outcomes, in terms of missed and interval cancer rates. Abstracts