Multiple factors influence the yield of colonoscopy for the detection of neoplasia.
Few studies until now have addressed the impact of colonoscopy duration on procedure yield.
Researchers from Minnesota, USA, designed a study to investigate whether endoscopist-specific procedure times correlate with the number and clinical significance of polyps detected at screening or surveillance colonoscopy.
Dr William Sanchez, Dr Gavin Harewood and Dr Bret Petersen reviewed procedural data from screening or surveillance colonoscopies performed at Mayo Clinic, Rochester MN, between January 1, 1996 and June 30, 2000.
|Direct correlation between colonoscopy procedure time and polyp yield|
|American Journal of Gastroenterology|
The group characterized individual endoscopists by their personal endoscopist procedure mean time (EPMT) to perform a negative colonoscopy.
Procedure time included patient's consent and sedation. The researchers then correlated individual polyp detection rates with EPMT.
In total, the researchers reviewed 10,159 colonoscopies, of which 4,312 (42.4%) yielded polyps.
Polyp detection varied among endoscopists between 19.0% and 62.3%.
The group found that there was a close correlation between EPMT and polyp yield (all sizes), although correlation was weaker for polyps >10 mm and polyps >20 mm.
Using multivariate analysis, they also found that longer mean endoscopist time was associated with colonic lesion detection.
In addition, longer mean procedure duration demonstrated a looser association with identification of polyps >10 mm, and polyps >20 mm.
The group concluded that there is a direct correlation between colonoscopy procedure time and yield, with a three-fold variation of polyp detection rates.
Dr Sanchez commented, "These results should prompt future prospective studies assessing the impact of colonoscopic withdrawal time on lesion detection."