Molecular and clinical risk markers in colon cancer trials

Although there is a great deal of information concerning the risk factors for colorectal cancer, progress has been slow in determining methods of chemoprevention. In part this is because colorectal cancer consists of a series of events over 10-15 years or more, which affects only 3-5% of the population. Risk markers for use in patient selection are needed to decrease the sample size needed. In addition, there is a need to identify intermediate endpoints of success to decrease the follow-up time. Clinical markers of risk are a history of colorectal adenomas and of inflammatory bowel disease. Molecular markers include a number of genetic markers and enzyme polymorphisms.