The Impact of Timed Colonoscopy Withdrawal on Adenoma Detection Rates at a Community Hospital

Abstract

Purpose: Colonoscopy is considered the gold standard for adenoma detection. A minimal withdrawal time of six minutes is suggested for adequate inspection of the colon for polyps. The aim of this study is to evaluate the long-term impact of timed withdrawal on adenoma detection rate. Methods: A retrospective analysis was done of adenoma detection rates before and after endoscopists were monitored for colonoscopy withdrawal time. The study was divided into 3 phases: Phase 1: Prior to timed colonoscopy withdrawal a baseline adenoma detection rate was determined over a 3 month period. Phase 2: Over a 3 month period endoscopist withdrawal time was recorded using a stopwatch only during colonoscopies not requiring polypectomy or biopsy. Phase 3: Adenoma detection rates were determined over a 3 month period after endoscopists were no longer timed. Polyp and adenoma detection rates were based on colonoscopies done for screening or personal history of polyps. Results: The study was done between May 2009 to February 2010 involving 13 experienced endoscopists with a mean experience of 18 years in practice (range 2 to 27 years). In phase 1, a total of 500 colonoscopies were reviewed and 54% (n=271) were males. The overall adenoma detection rate was 24%. The adenoma detection rates in males and females were 33% and 14% respectively. During phase 2, a total of 513 colonoscopies were timed for withdrawal with a mean of 9 minutes and 30 seconds (range 1:50 min to 23:00 min). In phase 3, a total of 500 colonoscopies were reviewed and 53% (n=263) males. The overall adenoma detection rate was 26%. The adenoma detection rates in males and females were 29.4% and 16% respectively. Conclusion: Colonoscopy withdrawal time has been shown to impact polyp detection rate, especially adenomas. In the current study, there was no statistical difference in adenoma detection rate among this group of endoscopists before and after timed colonoscopy withdrawal. The study suggests if endoscopists already have equal to or above average adenoma detection rate then a period of timed withdrawal may not impact adenoma detection.