A 58-year-old man with painless obstructive jaundice is evaluated for a mass in the head of the pancreas. Which serum tumor marker is most appropriate to support the diagnosis and monitor treatment response in this setting?
- A CA 15-3
- B CA 125
- C CA 19-9 ✓
- D Neuron-specific enolase
Correct answer: C. CA 19-9
Explanation
CA 19-9, a sialylated Lewis antigen carbohydrate epitope, is the standard serum marker for pancreatic adenocarcinoma; it is used for monitoring therapy and recurrence rather than screening. CA 125 is associated with epithelial ovarian carcinoma, CA 15-3 with breast carcinoma, and neuron-specific enolase with neuroendocrine tumors such as small cell lung cancer and neuroblastoma. Note that CA 19-9 can be falsely elevated in biliary obstruction itself.
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.