Association of Adenoma Detection Rate and Adenoma Characteristics With Colorectal Cancer Mortality After Screening Colonoscopy

Clin Gastroenterol Hepatol. 2021 Sep;19(9):1890-1898. doi: 10.1016/j.cgh.2021.04.023. Epub 2021 Apr 18.


Background & aims: The adenoma detection rate (ADR) and characteristics of previously resected adenomas are associated with colorectal cancer (CRC) incidence and mortality. However, the combined effect of both factors on CRC mortality is unknown.

Patients and methods: Using data of the Austrian quality assurance program for screening colonoscopy, we evaluated the combined effect of ADR and lesion characteristics on subsequent risk for CRC mortality. We analyzed mortality rates for individuals with low-risk adenomas (1-2 adenomas <10 mm), individuals with high-risk adenomas (advanced adenomas or ≥3 adenomas), and after negative colonoscopy (negative colonoscopy or small hyperplastic polyps) performed by endoscopists with an ADR <25% compared with ≥25%. Cox regression was used to determine the association of combined risk groups with CRC mortality, adjusted for age and sex.

Results: We evaluated 259,885 colonoscopies performed by 361 endoscopists. A total of 165 CRC-related deaths occurred during the follow-up period, up to 12.2 years. In all risk groups, CRC mortality was higher when colonoscopy was performed by an endoscopist with an ADR <25%. Compared with negative colonoscopy with an ADR ≥25%, CRC mortality was similar for individuals with low-risk adenomas irrespective of ADR (for ADR ≥25%: adjusted hazard ratio [HR], 1.22; 95% confidence interval [CI], 0.59-2.49; for ADR <25%: adjusted HR, 1.25; 95% CI, 0.64-2.43) and after negative colonoscopy with ADR <25% (adjusted HR, 1.27; 95% CI, 0.81-2.00). Individuals with high-risk adenomas were at significantly higher risk for CRC death if colonoscopy was performed by an endoscopist with an ADR <25% (adjusted HR, 2.25; 95% CI, 1.18-4.31) but not if performed by an endoscopist with an ADR ≥25% (adjusted HR, 1.35; 95% CI, 0.61-3.02).

Conclusions: Our study adds important evidence for mandatory assessment and monitoring of performance quality in screening colonoscopy. High-quality colonoscopy was associated with a lower risk for CRC death, and the impact of ADR was strongest for individuals with high-risk adenomas.

Keywords: Quality Assurance; Risk Stratification After Polypectomy; Screening Colonoscopy; Surveillance After Colonoscopy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoma* / diagnosis
  • Colonoscopy
  • Colorectal Neoplasms* / diagnosis
  • Early Detection of Cancer
  • Humans
  • Risk Factors