Diagnostic imaging by CT colonography and capsule endoscopy is used to detect colonic lesions.
Controversy exists regarding the work-up of subcentimetric lesions.
Dr Frank Thomas Kollig and colleagues from Germany identified risk indicators for advanced neoplasia in subcentimetric polyps.
The research team classified colonoscopies on the basis of the largest lesion found.
The team defined advanced neoplasia as high-grade dysplasia, villous histology, or cancer.
A risk index based on the logistic regression was generated, and the number needed to screen to detect advanced neoplasia was determined.
The team of doctors identified 1,077,956 colonoscopies, of which 106,270 were intermediate, and 198,954 were diminutive lesions.
The team found that 13% of intermediate, and 4% of diminutive lesions contained advanced neoplasia.
The risk of advanced neoplasia was higher in intermediate than in diminutive lesions.
Age 85 versus 45 years was associated with odds ratios of 2.4 for intermediate polyps, and 3.2 for diminutive polyps.
|At median risk index values, the number needed to screen was 9.3 with intermediate lesions|
The research team assessed that pedunculated versus sessile morphology was associated with a higher risk of advanced neoplasia in intermediate and diminutive lesions.
In the combined analysis for subcentimetric lesions, odds ratios were 2.7 for age 85 versus 45 years, 1.1 for male sex, 1.6 for occult blood, 1.3 for overt blood in stool, 1.3 for more than four lesions, and 2.2 for pedunculated versus sessile lesions.
The team of doctors found that at median risk index values, the number needed to screen was 9.3 in individuals with intermediate lesions, and 29.4 in those with diminutive lesions.
Compared with the number needed to screen of 15 of the whole cohort, the majority of intermediate, but a minority of diminutive, lesions were deemed at high risk of advanced neoplasia.
Dr Thomas's team concluded, "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."