The natural history of untreated duodenal and ampullary adenomas in patients with familial adenomatous polyposis followed in an endoscopic surveillance program

Background: Endoscopic surveillance is recommended for patients with familial adenomatous polyposis (FAP) because of the high prevalence of duodenal adenomas and the risk of periampullary cancer. The aim of this study was to assess the natural history of untreated duodenal and ampullary adenomas in FAP patients during surveillance. Methods: One hundred fourteen FAP patients who had 2 or more surveillance examinations were followed for a mean of 51 months (range, 10 to 151 months). Results: Duodenal polyps progressed in size in 26% (25 of 95), number in 32% (34 of 106), and histology in 11% (5 of 45) of patients. Morphology and histology of the main duodenal papilla progressed in 14% (15 of 110) and 11% (12 of 105) of patients, respectively. The histologic progression was mild except for one patient who developed a periampullary cancer. Conclusions: A minority of FAP patients had progression of endoscopic features and histology of duodenal polyps or the main duodenal papilla when followed over 4 years. An endoscopic surveillance interval of at least 3 years may be appropriate for the majority of untreated patients with FAP. Factors that stratify patients as being at the highest risk of periampullary cancer and thus requiring more intensive surveillance are yet to be determined.