A 58-year-old man presents with painless obstructive jaundice. CT shows a mass in the head of the pancreas. Which serum tumour marker is most useful in monitoring his response to treatment?
- A CEA
- B CA 19-9 ✓
- C CA 125
- D AFP
Correct answer: B. CA 19-9
Explanation
CA 19-9 is the standard tumour marker for pancreatic adenocarcinoma and is used to follow treatment response and detect recurrence, though it is neither sensitive nor specific enough for screening. CEA is used mainly in colorectal cancer, CA 125 in epithelial ovarian cancer, and AFP in hepatocellular carcinoma and germ cell tumours. Note that CA 19-9 cannot be produced by Lewis antigen negative individuals, a classic exam point.
Reference: Sabiston Textbook of Surgery, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.