Timing of insertion and withdrawal during colorectal polypectomy

Abstract

Objective To evaluate the effect and safety of colorectal polypectomy during insertion and withdrawal through analysis of the miss rate in different phases. Methods A total of 200 patients with colorectal polyps detected by endoscopy were divided into two groups randomly according to random number table method. In group A(n=101), polyps were removed during withdrawal only, while in group B(n=99), polyps<10 mm in diameter were removed during insertion in the second colonoscopy and the remainder and newly discovered polyps were removed during withdrawal of the colonoscopes. The miss rate, newly discovery rate, endoscopy time and complications were evaluated. And the possible risk factors were calculated with logistic regression analysis. Results In group A, 443 polyps were found during the first endoscopy, 403 polyps and 11 newly discovered were detected and removed during the second endoscopy, which were 414 polyps in total. While in group B, 437 polyps were found during the first endoscopy, 421 polyps and 28 newly discovered were detected and removed during the second endoscopy, which were 449 polyps in total. The pooled miss rate of polyps in group A was significantly higher than that in group B[8.8%(40/454)VS 3.4%(16/465), P<0.001]. The newly detection rate of polyps in group A was significantly lower than that in group B[2.4%(11/454)VS 6.0%(28/465), P=0.024]. The mean endoscopic procedure time in group A was significantly longer than that in group B[(32.2±5.8)min VS(25.5±5.0)min, P<0.001]. There were no complications such as perforation, massive hemorrhage and so on found in either group. Logistic regression analysis showed that number of polyps<10 mm(OR=8.471, 95%CI: 2.527-28.395), flat polyp(OR=10.865, 95%CI: 3.360-35.134)and location in the left colon(OR=7.631, 95%CI: 2.361-24.666)were significantly related to the miss rate of colorectal polyps(P<0.05). Conclusion Removal of polyps during withdrawal only is associated with a considerable higher miss rate of colorectal polyp.Removal of polyps<10 mm during insertion and excision of the remainder and the newly discovered polyps during withdrawal could yield to a lower polyp miss rate and a shorter endoscopic surgery time, and does not significantly increase the complications, but it is especially important for those patients to pay attention to high risks such as polyps<10 mm, flat type and those in left semicolon. Key words: Colonoscopy; Missed detection; Polypectomy; The timing of endoscopic surgery