Post-colonoscopy cancer rates in Scotland from 2012 to 2018: A population-based cohort study.

Aim: The aim of this work was to quantify post-colonoscopy colorectal cancer (PCCRC) rates in National Health Service (NHS) Scotland using World Endoscopy Association guidelines, compare incidence between health boards and referral streams and explore comparisons in results with published data from other healthcare systems.

Method: This is a population-based cohort study using NHS Scotland data between 2012 and 2018. All people undergoing colonoscopy between 2012 and 2018 and subsequently diagnosed as having bowel cancer up to 3 years after their investigation were included. The main outcome measures are national trends in the PCCRC rate at 3 years (PCCRC-3yr). with comparison between bowel screening and non-screening referral routes, board of referral and analysis of factors associated with occurrence.

Results: The overall unadjusted PCCRC-3yr was 7.9% (7.4%-8.3%). There was no change in the annual rate over the 7-year study period. The PCCRC rate was lower for the Scottish Bowel Cancer Screening Programme (6.7% vs. 8.3%), but compared unfavourably with rates reported by the NHS England Bowel Cancer Screening Programme from an earlier time period. There was wide variation in rates between health boards of similar population size. Rates were higher in women, with increasing age and in patients with a history of inflammatory bowel disease or diverticular disease.

Conclusion: Despite advances in technology, there has been no improvement in the PCCRC rate in Scotland between 2012 and 2018. Rates in bowel screening colonoscopy are better than in nonscreening colonoscopy but compare unfavourably with NHS England, possibly as a result of less robust endoscopist selection and training. Quality improvement is required in colonoscopy in order to improve patient outcomes nationally, and to allow equitable access to higher-quality colonoscopy in different regions of the country.