Review of Familial Adenomatous Polyposis: Current Understanding and Clinical Management.

Familial adenomatous polyposis (FAP) is an autosomal dominant hereditary colorectal cancer (CRC) syndrome caused by germline pathogenic variants in the () gene. FAP is typically characterized by the development of hundreds to thousands of adenomatous polyps throughout the colon and rectum, with a nearly 100% chance of developing CRC if left untreated. Duodenal cancer is the second leading cause of cancer for patients with FAP; however, gastric cancer has become more prevalent in recent years with improved surveillance of the colon, rectum, and duodenum. Patients frequently develop other extracolonic manifestations including desmoid disease, which holds the highest extracolonic mortality risk, and thyroid nodules, which are more frequently associated with the cribriform morular variant of papillary thyroid cancer. Management of FAP is complex, and patients require frequent and lifelong surveillance. This review will discuss the current understanding and clinical management of FAP as well as innovations and challenges in clinical practice.