A 58-year-old man presents with painless obstructive jaundice. Imaging shows a mass in the head of the pancreas. Serum levels of which tumor marker would be most useful in monitoring this patient's disease burden?
- A CA-125
- B Calcitonin
- C CA 19-9 ✓
- D Neuron-specific enolase
Correct answer: C. CA 19-9
Explanation
CA 19-9 is the principal serum marker for pancreatic adenocarcinoma and is used for monitoring treatment response and detecting recurrence, though it lacks sensitivity and specificity for screening. It is a Lewis antigen-related glycoprotein and is not elevated in Lewis antigen-negative individuals, a limitation worth remembering. CA-125 is associated with epithelial ovarian cancer, calcitonin with medullary thyroid carcinoma, and neuron-specific enolase with neuroendocrine tumors including small cell lung carcinoma.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.