Abstract:Objective To evaluate secondary withdrawal of colonoscope of left colon to improve adenoma detection rate. Methods A total of 200 patients who received colonoscopy at Department of Gastroenterology, Qinghai Provincial People""s Hospital from January to June 2024 were randomly assigned to either the experimental group (n=100) or the control group (n=100) by using the random number table. The experimental group underwent standardized 6-minute colonoscopy with retraction to the anus, followed by reinsertion to the splenic flexure, and a second withdrawal. The control group performed a single withdrawal from the splenic flexure to the anus with the withdrawal time doubled. Colorectal adenoma detection rates and adverse event rates of the two groups were compared, and logistic regression analysis was performed to identify influencing factors for adenoma detection rate. Results The detection rate of colorectal adenoma in the experimental group was higher than that in the control group [63.00% (63/100) VS 34.00% (34/100), χ2=16.835, P<0.05]. There was no significant difference in the incidence of adverse reactions between the two groups [4.00% (4/100) VS 5.00% (5/100), χ2=0.116, P>0.05]. Boston bowel preparation scale scores were higher in the experimental group (8.15±1.25 scores VS 6.12±1.45 scores, χ2=10.604, P<0.05). According to the logistic regression analysis, the included factors were age, gender, history of previous colonoscopy, history of abdominal surgery, operator, polyps detection during the first withdrawal, regression time of left colon and secondary withdrawal time of of left colon. The factors affecting the detection of colorectal adenoma were directly related to age, detection of polyps, polyps detection during the first withdrawal, regression time of the left colon, and secondary withdrawal time of the left colon (P<0.05). Conclusion With total withdrawal time held constant, a secondary withdrawal of the left colon significantly increases adenoma detection rate.