Question

A 65-year-old man presents to the emergency department after he had abnormally tarry-colored stool on multiple occasions. He has had gastrointestinal discomfort and has felt increasingly tired during the past 2 months. Physical examination reveals a guaiac- positive stool. A subsequently colonoscopy identified a circumferential mass in the sigmoid colon. A biopsy was performed, which identified the mass as an adenocarcinoma. CEA level was obtained as part of the presurgery workup.

Questions

1. Is the CEA test useful as a screening test for colon carcinoma?

2. What other conditions can result in elevated CEA levels?

3. How is CEA used to monitor patients after surgery for colon cancer?

Answer 1

1). Carcinoembryonic antigen (CEA) is a glycoprotein found in all normal mucosal cells. But their increased expression is associated with certain cancer types such as colorectal cancer and adenocarcinoma. So, it is used as one of the marker for colorectal cancer.

The CEA expression levels are most useful to monitor the disease status and to assess prognosis, rather than to confirm the diagnosis.

2). The elevated levels of CEA are also observed in adenocarcinoma.