Patients with FAP are not only at risk of developing colorectal adenomas but also at high risk of developing duodenal adenomas. In 30% to 92% of FAP patients duodenal adenomas are detected, with a lifetime risk approaching 100%. Of these duodenal adenomas, only a small proportion develops into duodenal cancer, with a prevalence of approximately 5-10% in FAP patients.~Endoscopic surveillance is nowadays the standard of care to prevent FAP patients from developing duodenal cancer. The severity of duodenal polyposis is assessed using the Spigelman classification system. This classification is based on the number, size, histology, and grade of dysplasia of the duodenal adenomas, resulting in a score varying from 0-IV, guiding surveillance intervals and treatment.~Concerns are rising on the accuracy of the Spigelman score as predictor for duodenal cancer, especially for ampullary cancer. Over the past years, multiple studies demonstrated limitations of this staging system including the fact that this classification does not adequately predict duodenal/ampullary cancer and does not guide endoscopic or surgical interventions. A clear endoscopic intervention protocol is needed, not only to prevent the development of cancer but also to prevent the need for duodenal surgery, since these surgical procedures are associated with high complication and mortality rates.~With this study, the investigators aim to evaluate a personalized surveillance and intervention protocol for the duodenum and stomach with the goal to prevent the development of advanced neoplasia (AN) by endoscopically removing lesions before they progress to AN.
The purpose of this study is to determine the efficacy and safety of a personalized surveillance and intervention protocol for duodenal and gastric polyposis in patients with familial adenomatous polyposis (FAP)