Endoscopy 2019; 51(08): 733-741
DOI: 10.1055/a-0919-4803
Original article
© Georg Thieme Verlag KG Stuttgart · New York

Risk of post-colonoscopy colorectal cancer in Denmark: time trends and comparison with Sweden and the English National Health Service

Lasse Pedersen
1  Department of Surgical Gastroenterology, Aalborg University Hospital, Aalborg, Denmark
Roland Valori
2  Department of Gastroenterology, Gloucestershire Hospitals, Gloucester, United Kingdom
Inge Bernstein
1  Department of Surgical Gastroenterology, Aalborg University Hospital, Aalborg, Denmark
Karen Lindorff-Larsen
3  Nordsim: Center for Skills Training and Simulation, Aalborg University Hospital, Aalborg, Denmark
Charlotte Green
4  Department of Emergency, Aarhus University Hospital, Aarhus, Denmark
Christian Torp-Pedersen
5  Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
› Author Affiliations
Further Information

Publication History

submitted: 16 November 2018

accepted after revision: 10 April 2019

Publication Date:
07 June 2019 (online)


Background The post-colonoscopy colorectal cancer (PCCRC) rate is a key quality indicator for colonoscopy. Previously published PCCRC rates have been difficult to compare owing to differences in methodology. The primary aim of this study was to compare Danish PCCRC rates internationally and to calculate Danish PCCRC rates using the World Endoscopy Organization (WEO) consensus method for future comparison. The secondary aim was to identify factors associated with PCCRC.

Methods National registries were used to examine the risk of PCCRC. The Danish 3-year rate of PCCRC (PCCRC-3yr) was calculated using previously published methods from England, Sweden, and the WEO. Poisson regression analysis was performed to identify factors associated with PCCRC.

Results The Danish PCCRC-3yr was significantly higher than the rate in the English NHS (relative risk [RR] 1.12, 95 % confidence interval [CI] 1.05 – 1.19) and Sweden (RR 1.15, 95 %CI 1.06 – 1.24). The Danish PCCRC-3yr based on the WEO consensus method fell from 22.5 % in 2001 to 7.9 % in 2012. The multivariable Poisson regression model found PCCRC to be significantly associated with diverticulitis (RR 3.25, 95 %CI 2.88 – 3.66), ulcerative colitis (RR 3.44, 95 %CI 2.79 – 4.23), hereditary cancer (age < 60 years: RR 7.39, 95 %CI 5.77 – 9.47; age ≥ 60 years: RR 3.81, 95 %CI 2.74 – 5.31), and location in the transverse (RR 1.57, 95 %CI 1.28 – 1.94) and ascending colon (RR 1.85, 95 %CI 1.64 – 2.08).

Conclusions The PCCRC-3yr was higher in Denmark than in comparable countries. Differences in colonoscopist training, background, and certification are possible contributing factors. A review of colonoscopist training and certification in Denmark, and continuous audit and feedback of colonoscopist performance may reduce PCCRC-3yr.