High Definition versus Standard Colonoscopy: Adenoma Detection in an Average Risk Screening Population in Clinical Practice

Purpose: High definition (HD) colonoscopy has the potential to identify more polyps, especially flat lesions which could be missed during a standard (SD) colonoscopy. This advantage may be important in screening in high risk patients. Its utility in average risk screening colonoscopy in clinical practice is unclear. Methods: 378 consecutive patients undergoing average risk screening colonoscopy with two experienced gastroenterologists over a six month period in one endoscopy center were included. 207 patients were examined with a standard scope in the initial 3 months, and 177 patients with high definition scope in the later 3 months. Patients with personal history of polyps, family history of colorectal neoplasia, inflammatory bowel disease, and those referred for reasons other than screening were excluded. Results: Both groups were well matched, mean age (56 vs 56.6 yrs)and sex (female 66% vs 68%). A total of 77 (37%) patients had at least one polyp detected during standard colonoscopy vs 74 (43%) of patients with high definition colonoscopy. The adenoma detection rate was 18% with standard colonoscopy vs 24% with high definition colonoscopy. These differences were not statistically significant (polyp detection p = 0.11, adenoma detection p = 0.18). The adenoma detection rates varied between the two endoscopists (SD 30% vs 11%, HD 30% vs 19%). The endoscopist with the lower adenoma detection rate had a younger and more female (77% vs 48%) population. Conclusion: High definition colonoscopy did not significantly improve adenoma detection rates in our average risk screening colonoscopy population. The adenoma detection rate is likely to be influenced more by the population studied and operator technique, than by the use of high definition colonoscopy during screening.Table: Polyp detection by HD and SD colonoscopyTable: Distribution of Polyps