BACKGROUND: Fecal immunochemical test (FIT) diagnostic accuracy for colorectal adenoma detection in colorectal cancer screening is limited. METHODS: We analyzed 474 asymptommatic subjects with adenomas detected on colonoscopy in two blinded diagnostic tests studies designed to assess FIT diagnostic accuracy. We determined the characteristics of adenomas (number, size, histology, morphology and location) and the risk of metacrhonous lesions (according to European guidelines). Finally,we performed a logistic regression to indentifiy those variables independently associated with a positive result. RESULTS: Advanced adenomas (AA) were found in 145 patients (75.6% distal and 24.3% only proximal to splenic flexure). Patients were classified as low (59.5%), intermediate (30.2%) and high risk (10.3%) according to European guidelines. At a 100 ng/mL threshold, FIT was positive in 61 patients (12.8%). Patients with AA (Odds Ratio-OR 8.8, 95% Confidence Interval-CI 4.76-16.25), distal AA (OR 6.7, 95% CI 1.9-8.8), high (OR 20.1, 95% CI 8.8-45.8) or intermediate risk lesions (OR 6, 95% CI 2.9-12.4) had more probabilities to have a positive test. The characteristics of adenomas independently associated were number of adenomas (OR 1.22, 95% CI 1.04-1.42), distal flat adenomas (OR 0.44, 95% CI 0.21-0.96), pedunculated adenomas (OR 2.28, 95% CI 1.48-3.5) and maximum size of distal adenomas (mm) (OR 1.24, 95% CI 1.16-1.32). CONCLUSIONS: European guidelines classification and adenoma location coORelates with the likelihood of a positive FIT result. IMPACT: This information allows us to understand the FIT impact in colorectal cancer prevention. Likewise, it should be taken into account in the development of new colorectal adenomas biomarkers.
- Received December 18, 2013.
- Revision received June 5, 2014.
- Accepted June 6, 2014.
- Copyright © 2014, American Association for Cancer Research.