 Background and study aim The relative risks of duodenal adenocarcinoma and ampullary carcinoma in Familial Adenomatous Polyposis FAP have been estimated 100 to 330 times higher than in general population. However risk factors, including a genotype-phenotype association for duodenal cancer in FAP has not been fully understood. The aim of this study is to determine risk factors associated with the development of advanced duodenal polyposis and ampullary adenomas in colectomized patients with FAP. 