Evaluation of serum AFP (α-fetoprotein) level in HBsAg carrier patients for diagnosis of hepatocellular carcinoma

Abstract

Background: Hepatocellular carcinoma (HCC) is common all over the world as well as Iran. The incidence of HCC is higher in hepatitis B carriers and it is highly recommended to periodically screen these patients by serum alpha-fetoprotein (AFP) and liver ultrasound (US) every 6 months. We explore the diagnostic accuracy and the performance of (AFP) in cases of hepatitis B carriers as a screening tool by using serum total AFP concentration of 20 ng/ml. Materials and Methods: The study included 2452 HBsAg carriers with no evidence of hepatocellular carcinoma or cirrhosis were followed up in a 6-year prospective surveillance program with testing by ultrasound and alphafetoprotein every 6 months referred to the Ahwaz JundiShapour university hospitals and hepatitis clinic (1999-2004). Men and nonpregnant women with an elevated AFP level were evaluated for the presence of HCC by ultrasound (US) examination. Hepatitis B surface antigen (HBsAg), anti-HBc antibody and alpha-fetoprotein (AFP) were determined in all cases by enzyme-linked immunosorbent assay (ELISA). Findings: One or more AFP elevations (higher than 20 ng/ml) were found in 32 cases, but 13 (45%) hepatocellular carcinomas were detected in these patients during follow up (9 men and 4 women). Of the 32 HBsAg carriers with AFP serum levels of more than 20 ng/ml, HCC was not detected in 19 cases (65%). The positive predictive value for AFP to detect HCC was only 31% for our AFP cut-off value, and the sensitivity and specificity was approximately 56 and 88%, respectively.The positive predictive value for ultrasound examinations to detect HCC was 64%, while the sensitivity and specificity was 90 and 92%, respectively. Conclusion: We conclude that AFP alone is not a useful marker for HCC screening because of its poor predictive value and low sensitivity, particularly in patients with underlying viral hepatitis B without cirrhosis and is not recommended except when ultrasonography is either not available or of poor quality. Ultrasonography seems more efficient and accurate as a screening tool.