Genetic alterations in sporadic and hereditary colorectal cancer: implementations for screening and follow-up

The genetics underlying an inherited predisposition to cancer are rapidly being uncovered. This fact may ultimately lead to the routine use of molecular tools to diagnose these disorders, and establish interventions to prevent the development of cancer. Among the multiple cancer family syndromes, several are known to be associated with the development of colon cancer. These disorders may be diagnosed during evaluation of the index patient or during screening of family members who are at risk. Although the effectiveness of screening and surveillance strategies is unproven in controlled clinical trials for any of these syndromes, the high cancer risk warrants screening, and reasonable recommendations can be made. Several other genetic syndromes are associated with gastrointestinal polyposis. The risk of colon cancer in these diseases is uncertain, and may not be increased and they are not mentioned in this review. Examples include Cowden disease, intestinal ganglioneuromatosis, Ruvalcaba-Myhre-Smith syndrome, Devon family syndrome, and Cronkite-Canada syndrome.