Basics
- Alpha-foetoprotein is a glycoprotein that is normally produced during gestation by the foetal liver and yolk sac.
- AFP is used as a tumour marker for hepatocellular carcinoma (HCC) & germ cell tumours.
Other conditions causing elevated AFP
- Pregnancy
- In a variety of other malignancies besides HCC & germ cell tumours, the commonest being gastric cancer
- Acute liver injury
Values of AFP
- Normal value of AFP is between 10 and 20 ng/dL.
- Serum levels greater than 400 ng/dL in a high-risk patient is diagnostic of HCC.
- After acute hepatic injury a rise in AFP up to 100 – 200ng/dL may occur.
- Patients with AFP levels >1000 have an extremely high risk of recurrent disease following transplantation, irrespective of the tumour size.
Drawbacks of AFP
- Not all tumours secrete AFP, and serum concentrations are normal in up to 40% of small HCCs.
- At levels >400ng/dL there is a high probability of HCC, but at these levels the tumour is usually widespread & hence the use of AFP as an early detector of HCC is limited.
- AFP levels are normal in the majority of patients with fibrolamellar carcinoma, a variant of HCC.
Family physician and AFP
- Cirrhosis underlies HCC in >80% cases
- Hence every patient of cirrhosis should be screened periodically for HCC with ultrasound & AFP.
- The family physician should clinically suspect HCC & therefore order AFP if a cirrhotic patient has:
o Worsening of jaundice
o Worsening of ascites
o Worsening of encephalopathy
o New variceal bleeding
o Abdominal pain, anorexia, weight loss, malaise
o Diarrhea or hypoglycemia (paraneoplastic manifestation)
o Hepatic bruit