The use of carcinoembryonic antigen in the clinical management of colorectal cancer.

Measurement of plasma levels of carcinoembryonic antigen, though not infrequently helpful in the mangement of patients with colorectal cancer, has serious limitations in terms of specificity and sensitivity. Many benign conditions may cause elevations of carcinoembryonic antigen, and even far advanced metastatic large bowel cancer may be associated with normal levels. Major treatment decisions should rarely, if ever, be based on plasma levels of carcinoembryonic antigen alone. Studies are currently underway to assess the value of serial levels of carcinoembryonic antigen in the early detection of recurrent disease with the hope of identifying patients who might be cured by secondary resections.