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PWE-010 Increase in polyp detection over 5 years mainly due to an increase in detection of sessile serrated polyps
  1. A Fraser,
  2. T Rose,
  3. and MercyAscot Hospital endoscopists
  1. Medicine, University of Auckland, Auckland, New Zealand


Introduction An overall increase in polyp detection rate is encouraging but is of uncertain benefit unless histology is also included confirming that significant polyps (TA and SSP) have been detected and removed. The detection of SSP may be encouraged by an audit process with yearly feedback meetings.

Method There has been a continuous audit process that has included histology at a MercyAscot, a private endoscopy clinic, from 2012 to 2016. There have been yearly feedback meetings to encourage endoscopists to improve performance. Polyp histology was recorded as adenomas (TA), sessile serrated polyps (SSP) and hyperplastic polyps (HP). Only endoscopists with more than 100 procedures were included. The number of TA and SSP per procedure was recorded from 2014. The mean number of TA and SSP is expressed per total number of procedures.

Results 12555 procedures were performed by 15 endoscopists. Polyp detection has increased over five years; 56.6% in 2012 to 65% in 2016. The detection rate for adenoma has remained stable after an initial increase in the second year of the audit (26% in 2012 to 31.5% in 2016). There has been a rapid increase in detection of SSP; 4.9% in 2012 to 17.1% in 2016. Twelve of 15 endoscopists increased their detection rate for SSP over the 5 years. Detection of hyperplastic polyps remained relatively constant at 25%–26%. There was no increase in polypectomy where no polyp was proven on histology (4% of procedures). The mean number of adenomas per procedure was unchanged; 0.60 in 2014, 0.56 in 2015 and 0.60 in 2016. The mean number of sessile serrated polyps per procedure was 0.26 in 2014, 0.32 in 2015 and 0.32 in 2016. The increase in detection of SSP has been achieved with only a small increase in mean withdrawal time (where polyps were not detected); 2012 8.1 mins, 2013 8.4 mins, 2014 8.3 mins, 2015 8.5 mins and 2016 8.4 mins. Three endoscopists were detecting SSP in more than 8% of procedures at the start of the audit (2012); 4 endoscopists started from less than 3%. Detection of polyps>1 cms decreased slightly from 10.7% in 2012 to 8.3% in 2016.

Conclusion The detection of SSP is a new skill that needs to be learnt over several years. The steady increase in overall polypectomy rate appears to be due to the detection and removal of SSPs that were previously undetected rather than the renaming of hyperplastic polyps by the pathology service. The different starting points and trends for each endoscopists would also support the conclusion that this trend is not due to reclassification by pathology service. The audit process could potentially increase the detection of diminutive polyps (mainly hyperplastic or no detected polyp) - i.e “gaming of the audit”. This has not occurred, perhaps because of the knowledge that histology was being evaluated.

Disclosure of Interest None Declared

  • audit
  • colonoscopy
  • polyp

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