Objective: Diagnostic imaging by CT colonography and capsule endoscopy is used to detect colonic lesions. Controversy exists regarding the work-up of subcentimetric lesions. The aim of this study was to identify risk indicators for advanced neoplasia (AN) in subcentimetric polyps.
Design: 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.
Results: 1 077 956 colonoscopies identified 106 270 intermediate (5-9 mm) and 198 954 diminutive (= 85 versus = 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.
Conclusion: This 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.
