Differences in proximal serrated polyp detection among endoscopists are associated with variability in withdrawal time

Gastrointest Endosc. 2013 Apr;77(4):617-23. doi: 10.1016/j.gie.2012.10.018. Epub 2013 Jan 12.


Background: Insufficient detection of proximal serrated polyps (PSP) might explain the occurrence of a proportion of interval carcinomas in colonoscopy surveillance programs.

Objective: To compare PSP detection among endoscopists and to identify patient-related and endoscopist-related factors associated with PSP detection.

Design: Prospective study in unselected patients.

Setting: Colonoscopy screening program for colorectal cancer at two academic medical centers.

Patients: Asymptomatic consecutive screening participants (aged 50-75 years).

Intervention: Colonoscopies were performed by 5 experienced endoscopists. All detected polyps were removed. Multiple colonoscopy quality indicators were prospectively recorded.

Main outcome measurements: We compared PSP detection among endoscopists by calculating odds ratios (OR) with logistic regression analysis. Logistic regression also was used to identify patient features and colonoscopy factors associated with PSP detection.

Results: A total of 1354 patients underwent a complete screening colonoscopy: 1635 polyps were detected, of which 707 (43%) were adenomas and 685 (42%) were serrated polyps, including 215 PSPs. In 167 patients (12%) 1 or more PSPs were detected. The PSP detection rate differed significantly among endoscopists, ranging from 6% to 22% (P < .001). Longer withdrawal time (OR 1.12; 95% confidence interval, 1.10-1.16) was significantly associated with better PSP detection, whereas patient age, sex, and quality of bowel preparation were not.

Limitations: Limited number of highly experienced endoscopists.

Conclusion: The PSP detection rate differs among endoscopists. Longer withdrawal times are associated with better PSP detection, but patient features are not. (

Clinical trial registration number: NTR1888.).

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoma / pathology*
  • Aged
  • Colonic Polyps / pathology*
  • Colonoscopy* / statistics & numerical data
  • Colorectal Neoplasms / pathology*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Observer Variation
  • Prospective Studies
  • Time Factors