Objective: To assess the safety and quality of baseline screening colonoscopy in a randomised controlled trial (RCT).

Methods: A population-based RCT with an explanatory design is ongoing to evaluate the efficacy of colonoscopy screening in 9751 men and women aged 40-74 years at average risk of colorectal cancer (CRC) in Japan. Screening colonoscopies for the intervention group were performed from June 2009 to June 2017.

Results: Of the 4861 participants in the intervention group, 4495 (92.5%) underwent screening colonoscopy. The quality of bowel preparation was excellent (34.8%) or good (45.6%) in 80.4% of cases. The caecal intubation rate was 99.7% (4483/4495), and the mean (±SD) withdrawal time was 9.7 (±5.3) min. The adenoma detection rate (ADR) was 39.4% (1770/4495). A total of 27 participants (0.6%) were diagnosed with CRC, and 266 (5.9%) were diagnosed with advanced neoplasia (AN). In women, adenomas were more frequently detected in the proximal colon than in the distal colon (proximal: 18.9% vs distal: 16.4%, p=0.024), and a similar trend was observed for AN (proximal: 2.4% vs distal: 1.5%, p=0.045). No serious adverse events related to screening colonoscopy were reported, and minor adverse events were observed in two participants (0.04%).

Conclusions: Adequate performance in compliance, ADR, and safety was confirmed in the intervention arm of the RCT evaluating the efficacy of screening colonoscopy. The high quality of screening colonoscopy observed in the trial suggests its feasibility as a population-based screening approach.

Trial registration number: UMIN000001980.

Keywords: COLONOSCOPY; COLORECTAL CANCER; COLORECTAL CANCER SCREENING.

© Author(s) (or their employer(s)) 2025. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ Group.

目标: 评估在随机对照试验（RCT）中基线筛查结肠镜检查的安全性和质量。

方法: 一项基于人口的RCT正在进行，以评估日本9751名40至74岁普通风险结直肠癌（CRC）男女性人群的结肠镜筛查效果。干预组的筛查结肠镜检查于2009年6月至2017年6月期间进行。

结果: 在干预组中的4861名参与者中，有4495人（92.5%）接受了筛查结肠镜检查。80.4%的病例肠道准备质量被评为优秀（34.8%）或良好（45.6%）。盲肠插管率为99.7%（4483/4495），平均（±SD）回撤时间为9.7（±5.3）分钟。腺瘤检出率（ADR）为39.4%（1770/4495）。共有27名参与者（0.6%）被诊断患有CRC，另有266人（5.9%）被诊断为高级别肿瘤病变（AN）。在女性中，近端结肠腺瘤检出率高于远端结肠（近端：18.9%，远端：16.4%，p=0.024），对于高级别肿瘤病变也有类似的趋势（近端：2.4%，远端：1.5%，p=0.045）。未报告与筛查结肠镜检查相关的严重不良事件，并且在两名参与者中观察到轻微的不良事件（0.04%）。

结论: 评估筛查结肠镜效果的RCT干预组中的合规性、ADR和安全性得到了充分确认。试验中观察到的高质量筛查结肠镜检查表明其可作为基于人口的筛查方法是可行的。

临床试验注册号: UMIN000001980.

关键词: COLONOSCOPY; COLORECTAL CANCER; 结直肠癌筛查。