1. Introduction
Colorectal cancer (CRC) is a major cause of morbidity and mortality worldwide. It is estimated that in 2008, 1233,000 new cases were diagnosed and more than 600,000 people died for this reason throughout the world. Colonoscopy is the technique of choice for both diagnosis and
PROBLEM DEFINITION Rectal cancer is a common disease in Western countries, increased with high age, male sex and obesity (1,2). As for other districts, premalignant intraepithelial neoplasia inside a rectal adenoma precedes the occurrence of invasive rectal cancer (3,4). Early endoscopic detection