Résumé : Prophylactic (procto-) colectomy is the treatment of choice to reduce the risk of colorectal cancer in FAP patients with multiple adenomas. Because patients present at young age, rectum-sparing surgery is sometimes advocated, so that there is no pelvic dissection with impact on quality of life, preserved pelvic innervation and sexual function and fertility. The main disadvantage of a total colectomy with an ileorectal anastomosis (IRA) is a rectal cancer risk of 50% at the age of 50 years and a cumulative risk of 25.8% after 25 years of follow-up. Therefore, this procedure should be reserved for patients with an unaffected rectum. There should be no discussion to perform a primary IPAA in patients with multiple rectal adenomas (> 20) or those with a severe dysplastic or large (> 3 cm) rectal adenoma or a cancer elsewhere in the colon. A patient with an IRA should undergo yearly follow-up by rectoscopy.