The value of tumor markers in colorectal cancer.

Currently CEA is the most accurate tumor marker for colorectal cancer. Preoperative determination of this marker can assist staging, treatment planning and in particular postoperative follow-up of colorectal cancer. Postoperative CEA monitoring should be performed every 3 months. Further evaluation for local recurrence or metastatic disease is mandatory if elevated or increasing CEA levels occur after radical surgery. However, present data do not justify using CEA alone for postoperative follow-up and monitoring of adjuvant therapy. Molecular genetic techniques are now increasingly performed to detect genetic alterations that can be used as prognostic markers. In the future, identification and quantification of these genes may even be valuable in defining the susceptibility of healthy individuals for colorectal cancer.