According to own data and similarly to previous published studies, patients diagnosed of Serrated Polyposis Syndrome undergoing annual surveillance after clearance of all serrated lesions ≥ 5mm, have a mean of 5 serrated lesions per patient at follow-up colonoscopies. The study was powered to establish a 25% significant increase in the mean of serrated lesions per patient in the Endocuff-assisted colonoscopy group. Accepting an alpha risk of 0.05, a beta risk of 0.2 and a loss rate of 10% in a bilateral contrast, a sample size of 124 patients (62 in each arm) are required to achieve statistic significance.