BACKGROUND AND AIMS Colorectal polyps are often detected during the insertion phase of colonoscopy but are commonly removed during the withdrawal phase. We aimed to investigate the clinical advantages of instant removal of colorectal polyps during the insertion phase to determine the appropriate strategy for polyps detected on insertion. METHODS This prospective, multicenter, randomized trial targeted patients with at least 1 left-sided polyp <10 mm in size detected unintentionally on endoscope insertion from April 2018 to March 2019. Patients were allocated to the following 2 groups: study group, consisting of patients who had polyp removal instantly on insertion, and control group, comprising patients who had the endoscope inserted to the cecum first and polyps removed subsequently on withdrawal. Carbon dioxide gas insufflation and cold polypectomy were applied to minimize the influences of polypectomy on endoscope insertion. Twenty advanced endoscopists from 7 community-based institutions participated in this trial. RESULTS Of 1451 patients enrolled, 220 patients were eligible for full assessment. Mean total procedure time was significantly shorter in the study group (18.9 vs 22.3 minutes, P < .001). Mean pure cecal intubation time and number of polyps per patient were similar between the 2 groups. In the control group, among 107 polyps found during insertion, 48 (45.8%) required reinspection and 7 (6.5%) were completely missed, with an average reinspection time of approximately 3 minutes. CONCLUSIONS Polypectomy during the insertion phase in the colon and rectum significantly shortens the total procedure time and eliminates all missed polyps without experiencing any disadvantages.

中文翻译：

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在结肠和直肠左侧插入阶段进行冷息肉切除术的临床重要性：一项多中心随机对照试验（PRESECT研究）。

背景与目的大肠息肉通常在结肠镜检查的插入阶段被检测到，但通常在撤回阶段被切除。我们的目的是调查在插入阶段即时清除结直肠息肉的临床优势，以确定在插入时检测到息肉的适当策略。方法这项前瞻性，多中心，随机试验的目标患者是在2018年4月至2019年3月内镜插入时无意中发现至少1例左侧息肉<10 mm的患者。患者被分为以下2组：研究组，由患者组成插入时立即切除息肉的对照组和对照组，包括先将内窥镜插入盲肠并在撤回时切除息肉的患者。应用二氧化碳气体吹入术和冷息肉切除术以最小化息肉切除术对内窥镜插入的影响。来自7个社区机构的20位高级内镜医师参加了该试验。结果在1451名患者中，有220名患者有资格接受全面评估。研究组的平均总手术时间显着缩短（18.9 vs 22.3分钟，P <.001）。两组之间的平均盲肠插管时间和息肉数量相似。在对照组中，在插入过程中发现的107例息肉中，有48例（45.8％）需要复检，而7例（6.5％）被完全漏诊，平均复检时间约为3分钟。