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

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 = 366) or vice versa (6-minute-first group, 6MF, n = 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 = 0.002), multiple adenomas miss rate (20.7% vs 56.5%, P = 0.01), and high-risk adenomas miss rate (14.6% vs 39.5%, P = 0.01) of 6MF without compromising detection efficiency ( P = 0.79). In addition, a lower false-negative rate for adenomas ( P = 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 = 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. DISCUSSION: In addition to increasing ADR, 9-minute m-WT also significantly reduces the AMR and AAMR of screening colonoscopy without compromising detection efficiency.

Classification of Barrett's epithelium by magnifying endoscopy.

BACKGROUND: The specialized columnar epithelium of Barrett's esophagus can be detected by obtaining random or 4 quadrant biopsy specimens at conventional endoscopy. However, little is known about the fine mucosal structure of specialized columnar epithelium. METHODS: Thirty patients with Barrett's esophagus were studied by magnifying endoscopy. The fine mucosal pattern (pit pattern) of 67 regions in Barrett's mucosa was recorded and compared with methylene blue staining. Histologic, mucin immunohistologic, and cell proliferation analyses of biopsy specimens were performed in relation to the pit patterns determined by magnifying endoscopy. RESULTS: Pit pattern was classified into 5 types. Tubular and villous pit patterns were not only characteristics of both specialized columnar epithelium and methylene blue absorption, but also possessed an intestinal mucin phenotype with a high Ki-labeling index, whereas other pit patterns (dot and straight) did not have specialized columnar epithelium and were categorized as the gastric phenotype. The long oval pit pattern had an intermediate phenotype between gastric and intestinal. CONCLUSIONS: The classification of the superficial mucosal appearance of Barrett's epithelium by magnifying endoscopy reflects not only histologic features but also mucin phenotypes.