Colonoscopy withdrawal time and polyp/adenoma detection rate: a single-site retrospective study in regional...

Bowel cancer is the second most common non-cutaneous cancer diagnosed in Australia among both genders. Colonoscopy withdrawal time of at least 6 min has been accepted as the standard to achieve the target polyp detection rate (PDR) and adenoma detection rate (ADR). A retrospective review was conducted in Bundaberg Hospital to evaluate the relationship between colonoscopy withdrawal time against polyp, adenoma and cancer detection rates.

A retrospective study was carried out in Bundaberg Hospital on patients who had colonoscopies performed between 1 October 2016 and 30 September 2017 by the general surgical team. Data collection was conducted by reviewing patient charts, general practitioner referral letters and endoscopy reports. Statistical analysis was performed with chi-squared test using Prism 8.2.1.

A total of 1579 colonoscopies were analysed. The median age of patients undergoing a colonoscopy was 64 years (95% confidence interval (CI) 60.55-61.93). Median total duration of colonoscopy was 19 min (95% CI 20.9-22.0), with median withdrawal time of 9 min (95% CI 10.06-10.95). PDR, ADR and sessile serrated adenoma (SSA) detection rates were 43.3%, 33.1% and 5.4%, respectively. Cancer detection rate was 2.8%. Longer withdrawal times were associated with higher PDR, ADR and SSA detection rates (P < 0.0001) and higher mean number of polyp/adenoma/SSA detected.

Colonoscopies with withdrawal times of less than 6 min did not achieve the target detection rates. It is clear that achieving the advocated withdrawal time for screening colonoscopy improves detection rates.