Risk factors for advanced neoplasia within subcentimetric polyps: implications for diagnostic imaging

Abstract

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 .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. 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.

Development and validation of the WASP classification system for optical diagnosis of adenomas, hyperplastic polyps and sessile serrated adenomas/polyps

“…Resecting all polyps, including all diminutive and small ones, also has its downsides considering complication risks and associated workload from gastroenterologists and pathologists 2 3. Compared with larger polyps (≥10 mm), small (6–9 mm) and diminutive (1–5 mm) polyps less often possess features of advanced neoplasia 4. Accurate optical diagnosis of small and diminutive polyps would allow to resect and discard these polyps without the need for histopathological assessment.…”

Sensitivity and specificity of CT colonography for the detection of colonic neoplasia after positive faecal occult blood testing: systematic review and meta-analysis

“…Additionally, screen-detected cancers are earlier stage than symptomatic tumours [14], and could be more difficult to detect at CTC. Furthermore, advanced histologic features are more common in gFOBt/FIT-positives, even at equivalent adenoma diameter [15,16]. Since CTC has less sensitivity for small polyps [10,17], this implies more advanced neoplasia will be missed when testing gFOBt/FIT-positive subjects than asymptomatic individuals, in whom subcentimetre adenomas rarely harbour advanced neoplasia [18].…”

Diminutive polyp cancers and the DISCARD strategy: Much ado about nothing or the end of the affair?

“…5 In a pooled review of 4 U.S. predominantly screening cohorts of 29,168 patients whose largest polyp was %5 mm in size, the cancer rate was 0.04% 11 ; however, this is in sharp contrast to 2 very large recent European cohorts with respectively more than 100,000 (positive fecal occult blood test result; M. Rutter, personal communication) and 360,000 (screening, surveillance and symptomatic) patients in which the rate of carcinoma in diminutive polyps was 0.1% to 0.4%. 5,12 This represents up to a 10-fold difference compared with pooled U.S. data for diminutive lesions, suggesting that there may be a difference in the rates of carcinoma in diminutive polyps depending on the indication for colonoscopy. We also know that not all polyps are equal in terms of malignant risk and that polyp morphology, particularly if there is a depressed area in the polyp, very substantially increases the risk that there might an invasive component.…”