DOES THE WITHDRAWAL TIME AFFECT ADENOMA DETECTION IN NON-SCREENING COLONOSCOPIES?

Aims:

There are no studies looking at the relationship between the colonoscopy withdrawal time (CWT) and adenoma detection rate (ADR) in non-screening patients. The aim of the study was to explore the relationship between the CWT and ADR, particularly in the right colon where colonoscopy has been thought to miss cancers.

Methods:

This is a retrospective study during November 2015- December 2016 of non-screening colonoscopies done at a large teaching hospital. Incomplete and therapeutic procedures were excluded. The 45 endoscopists included were 15 gastroenterologists, 10 colorectal surgeons and 20 trainee colonoscopists. CWT was calculated by reviewing the caecal intubation and rectal retroflexion images.

Results:

815 colonoscopies were included, with mean patient age of 58.4 years (SD 15). The mean ADR was 21.8% in the study. The CWT could be calculated for 61.2% of the cases (n = 499)

80% (399) of colonoscopies had CWT of ≥6 minutes. The mean CWT was 9.01 minutes (SD 4.18). The mean CWT of gastroenterologists was 10 minutes (SD 4), similar to the trainee group (10 minutes, SD 3), while the mean CWT for colorectal surgeons was 6 minutes (SD 3). The ADR for gastroenterologists was 27.4%, versus 16.3% for colorectal surgeons and 18.8% for trainees (P = 0.002). The ADR was positively correlated with longer CWT (r = 0.3, P = 0.000). The ADR was significantly higher when CWT was ≥8 minutes compared to CWT of less than 6 minutes or CWT of 6 – 8 minutes (P = 0.000). Higher number of polyps were detected on the right side of the colon when CWT was ≥8 minutes (P = 0.209).

Conclusions:

The majority of our procedures have CWT ≥6 minutes with good overall ADR. The CWT can differ between different colonoscopists. There is a moderately strong positive correlation between longer CWT and ADR. Meticulous withdrawal may improve polyp detection on the right side of the colon.