ABSTRACT
The biology of colorectal cancer provides opportunities for preventive strategies based on the early detection of curable cancer or removable adenoma. The process of cancer development (as described in Chapter 3) consists of multiple steps; some events (especially polypoid adenomas and microscopic, or occult, bleeding) are recognizable clinically at premalignant stages. The process extends over a considerable period of time, possibly as long as 10 years in non-familial cancers. Figure 8.1 shows in diagrammatic form how various forms of tests can be applied to the stages of tumorigenesis.
