Importance of CEA as a Tumor Marker

During investigation of a long-standing iron-deficiency anemia, a 67-year-old woman was found to have cecal colon cancer, Duke's stage B. A right hemicolectomy was performed at that time, and she had periodic follow-up examinations. Four years later, during a routine outpatient visit, her carcinoembryonic antigen (CEA) serum level was found to be 27.7 ng/mL (upper normal limit, 5 ng/mL). Four months earlier, her CEA level had been normal.