Tumour Markers in Hepatobiliary and Pancreatic Cancer

1. Hepatocellular Carcinoma (HCC)

Alpha-Fetoprotein (AFP)

• Reference range: < 20 ng/mL
• Diagnostic threshold: Values > 400 ng/mL in association with a liver mass are considered diagnostic in most cases. Markedly elevated levels (> 10,000 ng/mL) are essentially diagnostic in the right clinical context.
• Sensitivity: Elevated in > 90% of patients in high-prevalence regions (e.g., China/Southeast Asia). However, AFP may be normal in up to 40% of HCC patients in Western cohorts - sensitivity at the standard 20 ng/mL cut-off is approximately 60%.
• Specificity: AFP is also elevated in non-seminomatous germ cell tumours, pregnancy, regenerating livers in acute liver failure, and benign liver disease (cirrhosis, hepatitis) - so false positives occur.
• Surveillance: Used with ultrasound every 6 months for surveillance in high-risk patients (cirrhosis, chronic hepatitis B/C). A progressively rising AFP is highly suggestive of HCC.
• Prognosis: AFP > 1000 ng/mL predicts worse outcomes with liver transplantation. The HCC-MELD score combines AFP, MELD, and tumour size to predict post-transplant survival.

• Henry's Clinical Diagnosis and Management by Laboratory Methods (AFP section)
• Sleisenger and Fordtran's Gastrointestinal and Liver Disease (AFP/HCC section)
• Miller's Anesthesia, 10th ed., p. 1497-1498

AFP-L3 (Fucosylated AFP)

• AFP-L3 (Lens culinaris agglutinin reactive fraction) is the fucosylated subfraction.
• Cut-off: > 10% of total AFP is considered positive.
• Improves specificity over total AFP, particularly when total AFP is in the borderline range (10-200 ng/mL).
• Generally less sensitive than total AFP but more specific for HCC.
• Studies have not confirmed that AFP-L3 has superior sensitivity or specificity for early HCC compared to AFP alone.
• FDA-approved for risk stratification in the US, but not for routine HCC surveillance.

• Sleisenger and Fordtran's, Fucosylated AFP section

Des-Gamma-Carboxyprothrombin (DCP) / PIVKA-II

• Raised in most patients with HCC.
• High specificity for HCC.
• Shorter half-life than AFP - therefore more useful for monitoring treatment response and recurrence after ablation, resection, or TACE.
• Also associated with worse survival.
• Combined AFP + PIVKA-II gives higher sensitivity and specificity than either alone.
• FDA-approved for risk stratification, not screening.

• Miller's Anesthesia, 10th ed., p. 1497-1498
• Sleisenger and Fordtran's, Des-γ-Carboxy Prothrombin section
• Yamada's Textbook of Gastroenterology, 7th ed.

GALAD Model

• Gender
• Age
• AFP-L3%
• AFP
• DCP (PIVKA-II)

• Yamada's Textbook of Gastroenterology, 7th ed., Surveillance section

Emerging HCC Biomarkers

• Circulating tumour DNA mutations
• Differentially methylated DNA regions
• microRNAs (miRNA) and long non-coding RNAs (lncRNA)
• Exosomal biomarkers (tumour cell-derived exosomes show differential biomolecule expression)
• VEGF (elevated serum VEGF correlates with metastasis and shorter survival in HCC)

2. Cholangiocarcinoma (Bile Duct Cancer)

CA 19-9

• The most commonly elevated marker in cholangiocarcinoma.
• Major limitation: CA 19-9 is falsely elevated by biliary obstruction and cholangitis (the very conditions that cholangiocarcinoma causes), severely limiting its diagnostic accuracy.
• In patients with Primary Sclerosing Cholangitis (PSC), a cut-off of 100 IU/mL has sensitivity of 89% and specificity of 86% for cholangiocarcinoma.
• Elevated perioperative CA 19-9 levels are independent predictors of poor survival in patients with resectable cholangiocarcinoma.

CEA (Carcinoembryonic Antigen)

• Bile CEA levels are reportedly elevated in cholangiocarcinoma but not in benign diseases (other than intrahepatic stones).

Combined CA 19-9 + CEA Index (King's College Index)

• The King's College group developed a combined index incorporating both CEA and CA 19-9.
• This combined approach achieves similar or improved sensitivity for cholangiocarcinoma in PSC compared to CA 19-9 alone.

• Yamada's Textbook of Gastroenterology, 7th ed., Cholangiocarcinoma section
• Current Surgical Therapy, 14th ed.

3. Pancreatic Ductal Adenocarcinoma (PDAC)

CA 19-9 - The Primary Marker

1. Lewis antigen negativity: ~5-10% of the population lacks the enzyme to produce CA 19-9. These patients will never have detectable levels regardless of tumour burden.
2. Biliary obstruction raises CA 19-9 independently of cancer (false positives).
3. Elevated in other cancers: biliary (95%), stomach (5%), colon (15%), liver/HCC (7%), lung (13%).
4. Least sensitive for small, early-stage tumours - not effective for screening.

• Staging: Preoperative levels < 100 IU make occult metastatic disease unlikely; staging laparoscopy may be omitted. Levels > 130 U/mL predict tumour unresectability (HR 2.7).
• Prognosis: Higher levels correlate with higher tumour stage and poorer outcome. Preoperative values > 50 U/mL are associated with higher recurrence risk.
• Treatment monitoring: Falling CA 19-9 during chemotherapy/radiotherapy is a surrogate for clinical response. A rising level in the absence of biliary obstruction suggests progressive disease.
• Recurrence detection: A post-resection rise in CA 19-9 precedes clinical or imaging evidence of recurrence.
• After curative resection, patients whose CA 19-9 returns to normal survive longer than those whose levels remain elevated.

• Sabiston Textbook of Surgery, CA 19-9 section, p. 1221-1222
• Henry's Clinical Diagnosis and Management by Laboratory Methods
• Mulholland and Greenfield's Surgery, 7th ed.

CEA (Carcinoembryonic Antigen)

• Elevated in only 40-45% of pancreatic carcinoma patients - inferior to CA 19-9.
• Used as a secondary/adjunct marker.
• Combined CA 19-9 + CEA + osteopontin (OPN) + hepatocyte growth factor (HGF) + KRAS DNA probes: a multi-marker approach has shown improved sensitivity for early-stage pancreatic cancer detection.

CA 19-5 and CA 50

• CA 50 lacks a fucose residue compared to CA 19-9 and can be produced in Lewis-negative individuals (complementing CA 19-9 in those patients).
• CA 19-5 reacts with both Le^a and sialyl-Le^a epitopes.
• CA 19-9 and CA 50 are complementary - their simultaneous use may improve sensitivity in detecting pancreatic and other carcinomas.

Emerging Pancreatic Cancer Markers

• GPC-1 (Glypican-1): Exosomal glypican-1 has shown diagnostic promise - a 2024 meta-analysis (PMID: 38470244) assessed circulating exosomal GPC-1 as a diagnostic and prognostic marker in pancreatic cancer.
• Exosomal markers: A 2025 systematic review (PMID: 39953585) evaluated the diagnostic accuracy of exosomes in pancreatic cancer.
• sialylated tumour-related antigen (sTRA): A newly discovered glycan produced by a different subset of pancreatic adenocarcinomas than those that produce CA 19-9 - potentially complementary.
• KRAS oncogene: Expressed in > 90% of pancreatic cancers; DNA probes for mutant KRAS in serum are being studied for early detection.

Summary Table