Monitoring Methodologies

Current post-treatment monitoring for detecting recurrence of colorectal cancer employs serial measurements of carcinoembryonic antigen (CEA) in peripheral blood. The clinical limitations of CEA have been well documented and, as documented in over 50 studies reviewed by ASCO, include:

Clinical Limitations of CEA

Sensitivity <70% detection (range 17% to 89%)
False Positives Rate approximately 30% (range 17% to 89%). False positives may also be attributed to physiologic factors, inflammatory conditions and other malignancies.
Methods Variations Inconsistent CEA methodology can adversely affect equivalency of test values for individual patients.
Repeat Testing Serial measurements showing elevated CEA levels must often be confirmed by repeat testing.