The following is a summary of “Reduced Adenoma Miss Rate With 9-Minute vs 6-Minute Withdrawal Times for Screening Colonoscopy: A Multicenter Randomized Tandem Trial,” published in the May 2023 issue of Gastroenterology by Zhao, et al.
The association between a 9-minute mean withdrawal time (m-WT) and optimal adenoma detection rate (ADR) was commonly reported. Still, the impact of a 9-minute m-WT on adenoma miss rate (AMR) and ADR in screening colonoscopy lacked confirmation from randomized trials.
A multicenter tandem trial was conducted in 11 centers to address the gap. A total of 733 asymptomatic participants were randomized into two groups: the 9-minute-first group (9MF, n = 366) and the 6-minute-first group (6MF, n = 367). Segmental tandem screening colonoscopy was performed with either a 9-minute withdrawal followed by a 6-minute withdrawal or vice versa. The primary outcome measured was the lesion-level AMR.
Analysis based on intention-to-treat showed that the 9MF significantly reduced the lesion-level AMR (14.5% vs. 36.6%, P < 0.001) and participant-level AMR (10.9% vs. 25.9%, P < 0.001) compared to the 6MF group. Furthermore, the 9MF group had lower miss rates for advanced adenomas (AAMR, 5.3% vs. 46.9%, P = 0.002), multiple adenomas (20.7% vs. 56.5%, P = 0.01), and high-risk adenomas (14.6% vs. 39.5%, P = 0.01) without compromising detection efficiency (P = 0.79). Additionally, the 9MF group exhibited lower false-negative rates for adenomas (P = 0.002) and high-risk adenomas (P < 0.05) and a lower rate of shortening the surveillance schedule (P < 0.001). The 9-minute m-WT was also associated with an improved ADR compared to the 6-minute m-WT (42.3% vs. 33.5%, P = 0.02). Importantly, the inverse association between m-WT and AMR remained significant even after adjusting for ADR, and the 9-minute m-WT was identified as an independent protective factor for AMR and AAMR.
In summary, a 9-minute m-WT increases ADR and significantly reduces AMR in screening colonoscopy without compromising detection efficiency. The findings highlighted the importance of a longer withdrawal time in optimizing the effectiveness of colonoscopic examinations.
