CEA monitoring in colorectal cancer. What you should know.

Carcinoembryonic antigen (CEA) monitoring in patients with stage I-IV colorectal cancer has been, and remains, a controversial issue in oncology practice. Recommendations vary from bimonthly monitoring to no monitoring in the surveillance setting (for stage I-III disease). In the metastatic setting, there are no clear guidelines for CEA follow-up, although continued monitoring in such patients is common in the oncology community. This manuscript reviews the accuracy of CEA testing, its value as a prognostic indicator, and its role in surveillance and response assessment. The limitations of the test in the adjuvant and metastatic settings are illustrated through several case reports from the Colorectal Oncology Clinic at Roswell Park Cancer Institute. Guidelines for CEA monitoring are provided, based on a detailed literature review and institutional experience.