Improved Detection Rate Of Proximal Adenomas With Segmental Reexamination In The Proximal Colon:A Randomized Controlled Trial

BackgroundColonoscopy is regarded as the gold standard for the detection of colorectal neoplasia and polypectomy could reduce the risk of colorectal cancer(CRC)and mortality.However,interval CRCs being detected after recent colonoscopy were associated with missed lesions.The adenoma detection rate(ADR)has been accepted as an independent predictor of interval CRC risk and one of the most important quality indicators for colonoscopy.Therefore,it is desirable to develop a practical technique for increasing ADR to prevent interval CRC.The proximal location of prior adenomas at baseline was significantly associated with increased risk for subsequent advanced neoplasia.Thus,there is currently great interest in improving polyp detection in the proximal colon.We developed segmental re-examination of the proximal colon in which the proximal colon was examined twice segmentally to make it more practicable and to improve the proximal ADR.Aims(1)To investigate the efficacy of segmental re-examination in proximal colon on proximal adenoma detection rate(ADR).(2)To evaluate the time-effectiveness of segmental re-examination in proximal colon.(3)The effect of segmental re-examination on the surveillance interval recommendations.MethodsIntermediate or high-risk patients according to Asia Pacific CRC screening score were recruited prospectively in endoscopy center of Qilu hospital from November 2015 to May 2016.They were randomly assigned to segmental re-examination(SR)group and a control group.In the segmental re-examination group,the proximal colon was examined twice segmentally.The colonoscope was withdrawn to the hepatic flexure after the cecum successfully intubated.Then the colonoscope was intubated to the cecum again for second inspection.The same procedure was performed in the transverse colon and splenic flexure.In the control group,the withdrawal procedure was normal,but the withdrawal time in proximal colon was 4min at least.Bowel preparation was evaluated and recorded according to Boston Bowel Preparation Scale(BBPS).Withdrawal time was recorded segmentally and compared.Polyp characteristics were recorded,including location,size,and morphology.All polyps were evaluated by pathologists.Detection rates were calculated and compared for all polyps and adenomas of the proximal.Logistic regression analysis was performed to evaluate predictors of detecting at least one adenoma on the second examination of the proximal colon.ResultsA total of 360 patients(mean age 54.9 ± 10.7 years)were included in this study(SR 178 vs.control 182).The baseline in the two group was equivalent.In the segmental re-examination group,214 polyps in total were detected with 134 proximal polyps and 98 proximal adenomas.By contrast,205 polyps were detected with 104 proximal polyps and 65 proximal adenomas in the control group.The proportion of polyps and adenomas in proximal colon were higher in segmental re-examination group than that in the control(P = 0.014 and 0.008,respectively).The proximal ADR in the segmental re-examination group was higher(SR 33.1%vs.control 23.6%,P = 0.045)than that of the control group.The mean proximal adenomas in the segmental re-examination group was greater than that in the control(0.54 vs 0.36,P =0.036).During the second withdrawal in the segmental re-examination group,38 adenomas were detected,of which 94.7%were flat elevated or sessile.For the withdrawal time.,the duration of proximal withdrawal(SR 4.29±1.23 min vs.control 4.34±1.36 min,P＝0.739)was similar in two groups.In addition,there was no statistically significant difference in the total duration of the colonoscopy between the two groups(7.56±1.59 vs.7.88±1.91,P=0.090).There was a decreased surveillance interval in 19 patients(10.7%,19/178)in segmental re-examination group.The mean surveillance intervals before re-examination and after that were 8.16±2.48 year and 4.16 ± 1.02 year(P<0.001),which makes the surveillance time 4.00±1.63 ahead.The logistic regression analysis suggested that proximal withdrawal time was a significant predictor for detecting at least one adenoma during the second withdrawal in the proximal colon(OR = 0.27,95%CI 0,70-0.11,P = 0.007).ConclusionsThe segmental re-examination in proximal colon could increase proximal ADR and numbers of proximal adenomas,which could be accomplished easily and safely without increasing examination time.