IN THE ABSENCE OF ENDOSCOPIC MONITORING: The risk of colorectal cancer is higher than in the general population in patients presenting an adenoma with a diameter of more than 1 cm, and/or comprising villous structures and/or severe dysplasia. The risk is not increased in the presence of one or two tubular adenomas measuring less than 1 cm and without severe dysplasia. It has been demonstrated that endoscopic monitoring decreases the incidence and mortality of colorectal cancers in these patients. MONITORING MODALITIES: A control colonoscopy, 3 years after polypectomy is sufficient in most cases. Colonoscopy is recommended within the 3 months following exeresis of a transformed sessile adenoma, in order to check that the polypectomy was complete. A control colonoscopy can be performed 1 year later in the rare cases presenting more than 3 adenomas, with one measuring more than 1 cm. When the control colonoscopy is normal, one can wait at least five years before conducting a further control.