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.

Results of physical examination, ECG, complete blood cell (CBC) count, and biochemical tests were all normal, but a chest film revealed a large rounded mass (arrow) in the lower lobe of the left lung. CT of the thorax showed a 6 × 5-cm rounded, well-demarcated mass (arrow). CT of the abdomen and colonoscopy were unrevealing. Fine-needle aspiration under CT guidance was attempted without success. Serology was negative for Echinococcus species.

Referred for an open lung biopsy, the patient underwent lobectomy of the left lower lobe. Pathologic examination disclosed metastatic mucinous adenocarcinoma of moderate differentiation, coming from the colon. The patient's postoperative course was uneventful. Three months later, she was feeling well; her CBC count and biochemical parameters were normal, and her CEA level was 2.8 ng/mL.

Drs Haralampos Milionis, Evangelos Briasoulis, and Moses Elisaf of Ioannina, Greece, write that this case underlines the significance of CEA as a tumor marker during the follow-up of patients who have gastrointestinal malignancies. Even a slight increase in serum levels of this antigen should prompt thorough investigation for recurrence or metastatic disease.