Risk factors for advanced neoplasia within subcentimetric polyps: implications for diagnostic imaging
Gut, 05/24/2012
Clinical Article
Kolligs FT et al. – The study successfully identified risk factors and established a risk index for subcentimetric lesions. This has implications for the work–up of patients with subcentimetric lesions identified on diagnostic imaging.
Methods- Colonoscopies were classified on the basis of the largest lesion found.
- AN was defined as high–grade dysplasia, villous histology, or cancer.
- Logistic regression models were developed to identify risk factors for AN, and validated on separate datasets.
- A risk index based on the logistic regression was generated, and the number needed to screen (NNS) to detect AN was determined.
- 1077956 colonoscopies identified 106270 intermediate (5–9 mm) and 198954 diminutive (≤4 mm) lesions; 13% of intermediate and 3.7% of diminutive lesions contained AN.
- The risk of AN was higher in intermediate than in diminutive lesions (OR 3.1; 95% CI 3.0 to 3.3).
- Age ≥85 versus <45 years was associated with ORs of 2.4 (95% CI 1.8 to 3.1) for intermediate polyps and 3.2 (95% CI 2.3 to 4.5) for diminutive polyps.
- Pedunculated versus sessile morphology was associated with a higher risk of AN in intermediate (OR 2.0; 95% CI 1.9 to 2.2) and diminutive (OR 3.5; 95% CI 2.9 to 4.1) lesions.
- In the combined analysis for subcentimetric lesions, ORs were 2.7 (95% CI 2.2 to 3.3) for age ≥85 versus <45 years, 1.1 (95% CI 1.1 to 1.2) for male sex, 1.6 (95% CI 1.4 to 1.7) for occult blood, 1.3 (95% CI 1.2 to 1.5) for overt blood in stool, 1.3 (95% CI 1.2 to 1.4) for more than four lesions, and 2.2 (95% CI 2.1 to 2.3) for pedunculated versus sessile lesions.
- At median risk index values, the NNS was 9.3 (95% CI 9.1 to 9.5) in individuals with intermediate lesions and 29.4 (95% CI 28.5 to 30.2) in those with diminutive lesions.
- Compared with the NNS of 15 of the whole cohort, the majority of intermediate, but a minority of diminutive, lesions were deemed at high risk of AN.
