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 Kolligs and colleagues from Germany identified risk indicators for advanced neoplasia in subcentimetric polyps.
Colonoscopies were classified on the basis of the largest lesion found.
The doctors noted that advanced neoplasia was defined as high-grade dysplasia, villous histology, or cancer.
Logistic regression models were developed to identify risk factors for advanced neoplasia, and validated on separate datasets.
The research team examined that a risk index based on the logistic regression was generated, and the number needed to screen to detect advanced neoplasia was determined.
The team identified 1,077,956 colonoscopies, of which 106,270 were intermediate and 198,954 diminutive lesions.
The research team found that 13% of intermediate, and 4% of diminutive lesions contained advanced neoplasia.
The doctors assessed that the risk of advanced neoplasia was higher in intermediate than in diminutive lesions.
|4% of diminutive lesions contained advanced neoplasia|
Age 85 versus 45 years was associated with odds ratio of 2.4 for intermediate polyps, and 3.2 for diminutive polyps.
The team of doctors reported that the 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 ratio 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 research team examined 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 Kolligs's team commented, "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."