Reduced Adenoma Miss Rate With 9-Minute vs 6-Minute Withdrawal Times for Screening Colonoscopy: A Multicenter Randomized Tandem Trial

Abstract

INTRODUCTION: Although the 9-minute mean withdrawal time (m-WT) is often reported to be associated with the optimal adenoma detection rate (ADR), no randomized trials of screening colonoscopy have confirmed the impact of a 9-minute m-WT on adenoma miss rate (AMR) and ADR. METHODS:A multicenter tandem trial was conducted in 11 centers. Seven hundred thirty-three asymptomatic participants were randomized to receive segmental tandem screening colonoscopy with a 9-minute withdrawal, followed by a 6-minute withdrawal (9-minute-first group, 9MF, n 5 366) or vice versa (6-minute-first group, 6MF, n 5 367). The primary outcome was the lesion-level AMR. RESULTS:The intention-to-treat analysis revealed that 9MF significantly reduced the lesion-level (14.5% vs 36.6%, P < 0.001) and participant-level AMR (10.9% vs 25.9%, P < 0.001), advanced adenoma miss rate (AAMR, 5.3% vs 46.9%, P 5 0.002), multiple adenomas miss rate (20.7% vs 56.5%, P 5 0.01), and high-risk adenomas miss rate (14.6% vs 39.5%, P 5 0.01) of 6MF without compromising detection efficiency (P 5 0.79). In addition, a lower false-negative rate for adenomas (P 5 0.002) and high-risk adenomas (P < 0.05), and a lower rate of shortening surveillance schedule (P < 0.001) were also found in 9MF, accompanying with an improved ADR in the 9-minute vs 6-minute m-WT (42.3% vs 33.5%, P 5 0.02). The independent inverse association between m-WT and AMR remained significant even after adjusting ADR, and meanwhile, 9-minute m-WT was identified as an independent protector for AMR and AAMR.

9-Minute Withdrawal Time Improves Adenoma Detection Rate Compared With 6-Minute Withdrawal Time During Colonoscopy

“…The lower overall SDR in the 2 studies by Zhao et al is likely due to the lower rates of SDR in the Chinese population as well as only select centers with capable histopathologists reporting serrated lesions. 13,14 Desai et al; however, did not find an increased SDR with longer WT. 12 Their endoscopists had a high baseline SDR which might have been the factor making the extra WT unnecessary.…”

“…Two of these studies directly compared 6WT with 9-minute withdrawal time (9WT). 13,14 The third study demonstrated a range of WT and data were pooled for 8 to 10 minutes to assume a mean of 9WT. 12 The total number of included patients was 2159 of which 1136 patients were included in the 9-minute withdrawal group (9WT) and 1023 patients in the 6-minute withdrawal group (6WT) (Fig.…”

“…[12][13][14] The mean age range was 53.6 to 56.8 years and male gender was 50.7%. Two studies included patients undergoing colonoscopy for screening/surveillance purposes only, 12,14 whereas the third study included diagnostic colonoscopies as well. 13 Details of included studies are provided in Table 1.…”

“…High-quality evidence is needed to prove the efficacy of longer WT. To surmount these biases, high-quality randomized controlled trials (RCT) have been conducted to answer these questions recently 12–14 . To investigate the impact of WT on colonoscopy outcomes, we performed a systematic review and meta-analysis of RCTs investigating the effects of WT on colonoscopy outcomes to generate the highest level of evidence.…”

Lost in Translation? Avoiding Post-colonoscopy Colon Cancer

“…Likewise, there are data invalidating the common protocol of performing screening colonoscopy every 30 min with a withdrawal time of 6 min [2,3]. We have data [2] indicating that a 9-min withdrawal time vs. the standard 6-min withdrawal time (excluding polypectomy time) significantly reduces the adenoma miss rate (AMR; 14.6% vs. 36.6%) and the advanced adenoma miss rate (AAMR; 5.3% vs. 46.9%). Moreover, other data provide guidance for a more specific use of withdrawal time [3].…”