A prospective RCT comparing combined chromoendoscopy with water exchange (CWE) vs water exchange (WE) vs air insufflation (AI) in adenoma detection in screening colonoscopy

Abstract

Background A low adenoma detection rate (ADR) increases risks of interval cancers (ICs). Proximal colon flat polyps, e.g. serrated lesions (SLs), are difficult to find. Missed proximal colon flat lesions likely contribute to IC. Aims We compared chromoendoscopy with water exchange (CWE), water exchange (WE) and air insufflation (AI) in detecting adenomas in screening colonoscopy. Methods After split-dose preparation, 480 veterans were randomized to AI, WE and CWE. Results Primary outcome of proximal ADR (55.6% vs 53.4% vs 52.2%, respectively) were similar in all groups. Adenoma per colonoscopy (APC) and adenoma per positive colonoscopy (APPC) were comparable. Detection rate of proximal colon SLs was significantly higher for CWE and WE than AI (26.3%, 23.6% and 11.3%, respectively, p = 0.002). Limitations: single operator; SLs only surrogate markers of but not IC. Conclusions When an endoscopist achieves high-quality AI examinations with overall ADR twice (61.6%) the recommended standard (30%), use of WE and CWE does not produce further improvement in proximal or overall ADR. Comparable APC and APPC confirm equivalent withdrawal inspection techniques. WE alone is sufficient to significantly improve detection of proximal SLs. The impact of increased detection of proximal SLs by WE on prevention of IC deserves to be studied. This study is registered at ClinicalTrial.gov (NCT#01607255).

How to increase proximal adenoma detection rate: a meta-analysis comparing water exchange, water immersion and air/CO2 insufflation methods for colonoscopy

“…A total of 12 studies with 17 arms were included in the final analysis for this systematic review and meta-analysis ( Fig. 1) [23][24][25][26][27][28][29][30][31][32][33][34]. Of these, all were RCTs except one cohort study [32].…”

“…This further necessitates the improvement of techniques to increase detection of these proximal lesions. Only one study directly evaluated SSA/Ps, showing a significantly greater detection rate of these lesions using the WE method compared to the ACI method (23.6% vs. 11.3%, P<0.01) [23]. Our meta-analysis is important, as we pooled data from all available studies regarding proximal adenomas and our results demonstrate the superiority of the WE method in detecting these lesions; this, in turn, should increase the detection rate for SSA/Ps.…”

“…Study details and demographics of patients are summarized in Supplementary Table 3 and Table 1. Of all the studies included, 11 directly compared ACI to WE [23][24][25][26][27][28][29][30][31][32][33][34] and 4 directly compared ACI to WI [26,28,30,34]. The total number of patients included in these 11 studies was 5660 (2260 ACI, 2281 WE, 1119 WI).…”

“…Hsieh et al [34] Hsieh et al [30] Cadoni et al [26,27] Leung et al [24] Leung et al [23] Ramirez et al [31] Hsieh et al [34] Hsieh et al [30] Cadoni et al [26,27] Cadoni et al [29] Boroff et al [32] Overall (I^2=43.52 % , P= 0.088) 1 (Fig. 2B).…”

“…PADROverall, 8 studies reported PADR[23,24,27,[29][30][31][32]34]. The 8 arms comparing WE to ACI revealed a higher PADR for the WE group (WE: 29.7%, 95%CI 21.8-41.9% vs. ACI: 23.2%, 95%CI 14.1-33.8%; RR 1.30, 95%CI 1.11-1.53; P=0.001; I 2 =43.5%) (Fig.…”