Hereditary colon cancer: Lynch syndrome

Abstract

Colorectal cancer is the second leading cause of cancer-related deaths in the United States, with approximately 140,000 cases diagnosed and 50,000 deaths annually [1]. The majority of these cases are sporadic, occurring in individuals without any known familial predisposition. Approximately 10-30% of all colorectal cancer cases occur in the context of a family history [2], but most of the predisposing genetic factors have not yet been identified. Highly penetrant inherited colorectal cancer syndromes such as familial adenomatous polyposis (FAP), MYH-associated polyposis (MAP), and Lynch syndrome/hereditary nonpolyposis colon cancer (HNPCC) are less common but account for as many as 5% of colorectal cancer cases [3]. However, it is likely that this is an underestimate. With appropriate screening, an estimated 12,000 individuals could be diagnosed with Lynch syndrome on a yearly basis in the United States [4]. The ability to dramatically alter the clinical course of families with these syndromes mandates that clinicians understand the key features in the diagnosis and management of these hereditary colorectal cancer syndromes. Because of the absence of an overt polyposis phenotype, Lynch syndrome can be the most challenging hereditary colorectal syndrome to recognize. © 2010 Springer Science+Business Media, LLC.