Difference in adenoma detection rates according to colonoscopic withdrawal times and the level of expertise.

Background/aims: Adequate screening colonoscopy in the general population decreases the mortality associated with colorectal cancer through detection and removal of adenomatous polyps. Prolonged colonoscopic withdrawal times (>6 min) are reportedly beneficial for adenoma detection rates (ADRs). However, the quality of the endoscopist compared with colonoscopic withdrawal times is not known. The aims of this study were to investigate the difference in ADRs between trainees and experienced examiners.

Methods: A total of 967 consecutive patients who underwent screening colonoscopy in a single University hospital from June 2010 to November 2011 were enrolled in this prospective observational study. Colonoscopy was performed by four experienced staff and seven gastroenterology fellows.

Results: Seven gastroenterology fellows performed 633 colonoscopies and four experienced staff performed 334 colonoscopies. The overall detection rates of colorectal adenoma were 31.5% with ADRs of fellows and staff of 29.4% and 35.6%, respectively (p=0.047). Fellows also showed lower advanced ADRs (5.7% vs. 9.9%, p=0.016), and fellows had longer mean withdrawal times than staff (12.4±B1;4.9 min vs. 8.2±B1;4.1 min, p<0.001). Multivariate analysis showed significantly increased ADRs and advanced ADRs for staff compared with fellows (adjusted OR 2.41, 95% CI 1.70-3.43; adjusted OR 2.55, 95% CI 1.47-4.45, respectively).

Conclusions: ADRs were significantly lower when colonoscopy was performed by trainees, although withdrawal times were longer than those of staff. Our results demonstrated that the quality of colonoscopy, as measured by ADRs, may be improved by experienced examiners.