Prevention of colorectal cancer in high-risk populations: the increasing role for endoscopy and chemoprevention in FAP and HNPCC

Familial colorectal cancer (CRC) is heterogeneous. Screening recommendations do exist for individuals with a mild to moderate family history of CRC, with or without early age at onset. However, most attention has properly focused on the identification of individuals in whom a defined susceptibility gene mutation can be found. The past 20 years has seen the discovery genes for familial adenomatous polyposis (FAP), its variant forms (attenuated FAP and the recessive MYH-associated polyposis or MAP), nonadenomatous polyposes, and hereditary nonpolyposis CRC (HNPCC). A few retrospective and prospective studies support current recommendations for endoscopic surveillance in FAP and HNPCC, the main subjects of this paper. Where firm data have been lacking, various professional organizations have been very willing to provide consensus clinical practice guidelines. General guidelines need to be tailored to the peculiarities of a patient's circumstances, a task best accomplished in the hands of practitioners familiar with the natural history of the condition. Improvements in the technology of endoscopic treatment of adenomas now enable increasingly aggressive nonsurgical intervention. To this may be added opportunities for chemoprevention, currently consisting mainly of nonsteroidal anti-inflammatory drugs. Surveillance, chemoprevention, and imaginative hybrid surveillance/endoscopic therapy/chemoprevention trials may gradually decrease the present dependence on prophylactic colectomy/proctocolectomy.