Colon and rectal cancer: etiology and screening.

Our ultimate goal is primary prevention of colorectal cancer by delineating the etiologic factors in the pathogenesis of the disease and eliminating or modifying these factors. Further research is needed to accomplish this goal. In the meantime, early detection of colorectal cancer and its precursor lesions can be accomplished by methods currently available. Ultimately, a simple biochemical or immunologic test may become available which will identify individuals at high risk for colon cancer and may indicate that a very early lesion is present. This is the ultimate goal for secondary cancer prevention since the disease would then be discovered at a curable stage in almost all patients.