Review Question - QID 101117

The patient presents for a check-up following colorectal cancer. Serum carcinoembryonic antigen (CEA) levels are checked perioperatively and at regular follow-up intervals in patients who undergo resection for colorectal cancer. Increases in serum CEA levels are a specific indicator for disease recurrence.

CEA is a glycoprotein involved in cell adhesion. It is normally produced in fetal development and is not often found in the blood of healthy adults. Serum CEA levels can indicate colon, breast, or pancreatic malignancies, thus CEA alone is not useful for a colorectal cancer diagnosis. Instead, CEA levels are used to check for colon cancer recurrence following resection.

Perkins et al. review the clinical role of several serum tumor markers, including CEA. CEA is expressed in normal mucosal cells. It is overexpressed in several types of adenocarcinoma, but is found most frequently in colorectal cancer. Serum levels greater than 10 ng per mL are indicative of malignant disease.

Tan et al. reviewed the sensitivity and specificity of CEA in colorectal cancer recurrence. They found overall sensitivity of CEA for detecting CRC recurrence was 64% (95% CI: 61-67%). Specificity was 90% (95% CI: 89%-91%).

Illustration A shows the gross histology of an excised segment of colon. Two adenamatous polyps and 1 invasive cancer are labeled.

Incorrect Answers:
Answer 1: Alpha-fetoprotein is a marker for hepatocellular carcinoma.
Answer 3: CA-125 is used to monitor the response of ovarian cancer to treatment.
Answer 4: Gamma glutamyl transferase is a marker of biliary obstruction and/or alcoholism. It is frequently elevated in hepatocellular carcinoma.
Answer 5: CA-19-9 tumor marker is helpful in evaluating pancreatic cancer, including the nature of pancreatic masses.