Protocol design for randomized clinical trial to compare underwater cold snare polypectomy to conventional cold snare polypectomy for non-pedunculated colon polyps of size 5–10 mm (COLDWATER study)

Background: Colorectal cancer is internationally the third leading cause of death from a malignant disease. The aim of screening colonoscopy in adults > 45 years of age is early diagnosis and treatment of precancerous polyps. Endoscopic polyp removal (polypectomy) can be achieved with various techniques depending on the size, morphology, and location of the polyp. According to current guidelines, small non-pedunculated polyps should be removed with a cold snare after the colorectal lumen has been insufflated with air (conventional cold snare polypectomy).In recent years, several studies have described the benefits of water aided colonoscopy, as well as the safety and efficacy of underwater cold snare polypectomy for large colon polyps. However, there are insufficient data on conventional and underwater techniques for small polyps, the most commonly diagnosed colorectal polyps. Methods: We have designed a prospective randomized double-blind clinical trial to compare the safety and efficacy of conventional and underwater cold snare polypectomy for non-pedunculated polyps 5–10 mm in size. A total of 398 polyps will be randomized. Randomization will be carried out using the random numbers method of Microsoft Excel 2016. The primary endpoint is the muscularis mucosa resection rate. Secondary endpoints are the depth and percentage of R0 excisions, complications, and the recurrence rate at follow-up endoscopy 6–12 months after polypectomy. Discussion: We hypothesize underwater polypectomy will result in a higher muscularis mucosa resection rate. The results of our study will provide useful data for the development of guidelines in polypectomy techniques for non-pedunculated polyps 5–10 mm in size. Clinical trial registration: Clinicaltrials.gov, NCT05273697.