4. Discussion
polyps, polyp, adenoma
INTERNAL HEMORRHOIDS, PMR, INTESTINAL PERFORATION, ADENOMA
Colonoscopic retroflexion is an auxiliary examination technique widely used in clinical practice at present, mainly to observe the lower rectum and conveniently diagnose and treat internal hemorrhoids and lesions located near the anus. However, studies have shown that PMR in colonoscopy is as high as 22%,Researchers began to focus again on how to cost-effectively perform retroflexion to improve screening efficacy with conventional colonoscopy, as the performance of colonoscopic devices had improved, making the compliance of the colonoscope better and retroflexion easier than before. The study by HewettPreviously reported data of colonoscopic retroflexion in the ascending colon.AMR = adenoma miss rate, Na = not applicable, Nr = not reported, RCT = randomized controlled trial, PMR = polyp miss rate.However, Rex found that colonoscopic retroflexion in the second withdrawal of the ascending colon could not significantly reduce the miss rate of lesion. Meanwhile, the relevant literature did not recommend the use of colonoscopic retroflexion in the ascending colon during conventional colonoscopy due to its lack obvious benefits and its high operational risks, which may increase the risk of intestinal perforation.Although the results of colonoscopic retroflexion in the ascending colon were mixed in previous relevant studies from several years ago, the conventional colonoscopic devices and operational performance have been continuously updated. It has been reported that due to the wide lumen diameter of the ascending colon, experienced colonoscopists are usually able to perform the retroflexion of conventional colonoscopy in the ascending colon.The results of this trial showed that there was no statistically significant difference between the 2 group, indicating that cecal retroflexion observed during colonoscopy may not have much significance for adenoma missing in the ascending colon. The reasons for this could be attributed to the following: The trial period was hampered by the heavy impact of COVID-19 in China, resulting in an insufficient sample size. The evidence level from the preliminary report is limited, but it can be used as a reference for RCTs with sufficient sample size in our ongoing study post-pandemic; Even under moderate QBP, polyps could be found and resected in the visual field during forward examination; however, under cecal retroflexion observed, even with excellent QBP, polyps could only be observed in the 2 or 3 colonic folds closest to the cecum, making it difficult to identify polyps in the far ascending colon, particularly under poor QBP (Fig Colonoscopic images taken in the trial. (A) Moderate quality of bowel preparation (QBP) during forward examination, (B) Good QBP during forward examination, (C) excellent QBP under cecal retroflexion observed, and (D) poor QBP under cecal retroflexion observed.Of course, our trial is only a preliminary exploration at present, but in terms of clinical significance, it not only tests the scientificity and feasibility of the trial design, but also provides a reference for further RCTs in our next study. Moreover, it also takes a meaningful step towards quality control of colonoscopy. We believe that prospective studies with higher evidence levels will surely bring us more valuable information in the future.