Colonoscopy findings in high-risk individuals compared to an average-risk control population

Abstract

Background and aims: There is clear evidence of reduced morbidity and mortality from regular colonoscopy programs in patients with Lynch syndrome (LS). Today, also individuals with empirically increased risks of colorectal cancer (CRC) are offered colonoscopic surveillance. The aim was to compare the findings at the first screening colonoscopy in LS carriers, and individuals with an increased risk of bowel cancer due to family history of CRC with a control population. Methods: Altogether 1397 individuals with an increased risk for CRC were divided in four risk groups: one with LS carriers and three groups with individuals with different family history of CRC. The findings were compared between the different risk groups and a control group consisting of 745 individuals from a control population who took part in a population-based colonoscopy study. Results: In LS, 30% of the individuals had adenomas and 10% advanced adenomas. The corresponding figures in the other risk groups were 14–24% and 4–7%, compared with 10% and 3% in the control group. The relative risk of having adenomas and advanced adenomas was, compared to controls, significantly higher for all risk groups except the group with the lowest risk. Age was a strong predictor for adenomas and advanced adenomas in both risk individuals and controls. Conclusions: Individuals with a family history of CRC have a high prevalence and cumulative risk of adenomas and advanced adenomas, and screening is motivated also in this risk group.

Key Words:

• adenomas
• colonoscopy
• colorectal cancer
• familial
• hyperplastic polyps
• Lynch syndrome
• screening

Acknowledgements

The authors are grateful to Norma Lundberg for excellent administration throughout the study and to patients for their participation. Thank you to Elisabeth Berg for valuable statistical advice. The authors are also grateful to Göran Björck for linguistic revision. Thank you to the participants, the endoscopists and the research nurses at Ersta hospital for their work with the control population. Financial support was provided through the regional agreement on medical training and clinical research (ALF) between Stockholm County Council and Karolinska Institutet, and the Swedish Cancer Society.

Declaration of interest: None of the authors has any conflicts of interest to declare.