Effect of a time-dependent colonoscopic withdrawal protocol on adenoma detection during screening colonoscopy

Clin Gastroenterol Hepatol. 2008 Oct;6(10):1091-8. doi: 10.1016/j.cgh.2008.04.018. Epub 2008 Jul 17.


Background & aims: Screening colonoscopy can prevent cancer by removal of adenomatous polyps. Recent evidence suggests that insufficient time for inspection during overly rapid colonoscope withdrawal may compromise adenoma detection. We conducted a study of the effect of a minimum prespecified time for instrument withdrawal and careful inspection on adenoma detection rates during screening colonoscopy.

Methods: Baseline data consisted of neoplasia detection rates during 2053 screening colonoscopies performed without a specified withdrawal protocol. During a subsequent 13-month period we performed 2325 screening colonoscopies using dedicated inspection techniques and a minimum 8-minute withdrawal time. With colonoscopists comprising the study population, we compared overall and individual rates of neoplasia detection in postintervention procedures with those in baseline examinations.

Results: As compared with baseline subjects, postintervention subjects had higher rates of any neoplasia (34.7% vs 23.5%, P < .0001) and of advanced neoplastic lesions per patient screened (0.080 +/- 0.358 vs 0.055 +/- 0.241, P < .01). Twenty-five percent of advanced neoplastic lesions detected in postintervention examinations were 9 mm or less in diameter, versus 10% in baseline examinations (P < .001). Endoscopists with mean withdrawal times of 8 minutes or longer had higher rates of detection of any neoplasia (37.8% vs 23.3%, P < .0001) and of advanced neoplasia (6.6% vs 4.5%, P = .13) compared with those with mean withdrawal times of less than 8 minutes.

Conclusions: After implementing a protocol of careful inspection during a minimum of 8 minutes to withdraw the colonoscope, we observed significantly greater rates of overall and advanced neoplasia detection during screening colonoscopy.

MeSH terms

  • Adenoma / diagnosis*
  • Aged
  • Colonic Neoplasms / diagnosis*
  • Colonoscopy / methods*
  • Female
  • Humans
  • Male
  • Mass Screening / methods*
  • Middle Aged
  • Time Factors