Category: Colorectal Cancer Prevention
Townsville, Queensland, Australia
Colonoscopy is the gold standard bowel cancer screening test but it has reduced effectiveness for lowering colorectal cancer (CRC) rates due to widely reported missed detection rates for adenomas.
In our retrospective observational study featuring 10 colonoscopists and 3,169 colonoscopies, we measured the correlation between normal withdrawal time (NWT) and adenoma detection rate (ADR), between NWT and polyp detection rate (PDR), and between NWT and sessile serrated adenoma detection rate (SSADR) to assess the validity of the NWT as a determining factor of colonoscopy performance.
Methods: We excluded patients with age < 50 years, CRC history, inflammatory bowel disease history, poor or fair bowel preparation, and excluded colonoscopists who performed < 50 procedures or had < 6 months data. NWT was calculated from colonoscopies where no polyps were detected, and where no procedures were performed such as polypectomy, mucosal biopsy, haemorrhoid banding or thermal therapy. Linear regressions were used to calculate the strength of association between variables.
Results: The 10 colonoscopists had mean NWTs ranging from 5.8 to 9.6 minutes, ADR from 24.1 to 65.7%, and PDR from 31.3 to 77.9% (Table 1). Mean NWT correlated strongly with both ADR and PDR (r=0.64 and r=0.72, respectively; p< 0.05; Table 2). The correlation between NWT and SSADR did not reach statistical significance. The optimal NWT was between 9 to 10 minutes which was associated with the highest ADR and PDR in our group. SSADR correlated very strongly with both ADR and PDR with r values of 0.91 and 0.86, respectively.
Discussion: Our results reaffirm findings from previous studies, strengthening the likelihood that longer NWT is an independent factor that lead to improved adenoma detection, hence lowering future colorectal cancer rates. This one key performance indicator may allow more focused education and retraining to facilitate excellence in colonoscopy quality standards.
Table 1. Mean normal withdrawal time vs adenoma detection rate, sessile serrated adenoma detection rate and polyp detection rate
Table 2. Correlation between normal withdrawal time and detection rates
Lei Lin indicated no relevant financial relationships.
Myat Khaing indicated no relevant financial relationships.
Ruth Hodgson indicated no relevant financial relationships.
Ann Vandeleur indicated no relevant financial relationships.
Tony Rahman indicated no relevant financial relationships.