Institutional members access full text with Ovid®

Share this article on:

Risk factors associated with colorectal flat adenoma detection

Nicolás-Pérez, David; Parra-Blanco, Adolfo; Gimeno-García, Antonio Z.; Ortega-Sánchez, Juan A.; Carrillo-Palau, Marta; Jiménez-Sosa, Alejandro; Quintero-Carrion, Enrique

European Journal of Gastroenterology & Hepatology: March 2013 - Volume 25 - Issue 3 - p 302–308
doi: 10.1097/MEG.0b013e32835b2d45
Original Articles: Colorectal Neoplasia

Objectives Colorectal flat adenomas have been associated with a higher risk of colorectal malignancy. We describe demographic characteristics and endoscopic findings in patients with colorectal flat adenomas.

Methods In total, 1934 consecutive patients undergoing colonoscopy were prospectively included. Polyp shape was classified according to the Japanese classification. Chromoendoscopy was applied whenever a flat lesion was suspected. Indications for colonoscopy, demographic data, and characteristics of neoplastic lesions were recorded. Patients were classified as follows: group 1, no adenomas (n=1250); group 2, only protruding adenomas (n=427); group 3, protruding and flat adenomas (n=118); and group 4, only flat adenomas (n=139).

Results Approximately one in every 10 patients (13.2%) had flat adenomas. Among them, concomitant protruding adenomas were identified in approximately half of the cases. In multivariate analysis, age older than 50 years [odds ratio (OR)=1.62; 95% confidence interval (CI)=1.08–2.43, P=0.02], protruding adenomas (OR=2.17; 95% CI=1.65–2.87, P<0.001), follow-up colonoscopy for polyps or cancer (OR=2.22; 95% CI=1.59–3.10, P<0.001), screening colonoscopy (OR=1.60, 95% CI=1.15–2.22, P=0.005), and specifically trained endoscopist (OR=2.02, 95% CI=1.53–2.68, P<0.001) were associated independently with flat adenoma detection.

Conclusion Flat adenomas have specific demographic factors that might help to improve detection. Particularly, age older than 50 years, colorectal neoplasia surveillance, and the presence of protruding adenomas should alert endoscopists to the possible presence of these lesions. Trained endoscopists may offer a greater chance of detecting these lesions.

Department of Gastroenterology, Hospital Universitario de Canarias, La Laguna, Tenerife, Spain

Correspondence to Dr David Nicolás-Pérez, MD, PhD, Department of Gastroenterology, University Hospital of Canary Islands, Carretera La Cuesta/Taco, s/n, La Laguna, 38320 Santa Cruz de Tenerife, Spain Tel: +34 922 678 039; fax: +34 922 677 046; e-mail:

Received July 21, 2012

Accepted October 7, 2012

© 2013 Lippincott Williams & Wilkins, Inc.