The Combined Diagnostic Accuracy of Serum Alpha Fetoprotein and Des-Gamma Carboxyprothrombin in Hepatocellular Carcinoma among Chronic Liver Disease Patients in Ilorin

Abstract

Introduction : Chronic liver disease (CLD) is a disease of public health importance. CLD is defined as a clinical syndrome of liver disease lasting for at least six months with histology showing varying degree of hepatocellular necro-inflammation and fibrosis with or without neoplastic transformation. The disease is a spectrum that manifests initially as chronic hepatitis which may progress to liver cirrhosis and ultimately hepatocellular carcinoma (HCC). The current practice in the field of Gastroenterology has shifted from invasive methods of diagnosing HCC to non-invasive methods using tumor biomarkers. Various biomarkers of HCC have been proposed, but the largest body of evidence exists with alpha-fetoprotein (AFP). Most of the studies on the combined diagnostic accuracy of AFP and des - gamma - carboxyprothrombin (DCP) were done in other populations outside Nigeria. It is necessary to determine the combined diagnostic accuracy of the two tumor markers for early detection of HCC in North-central Nigeria. Materials and Methods : This study was a cross-sectional study and ethical clearance was obtained from the ethical and research committee of UITH, Ilorin. A total of 190 participants consisting of 125 cases and 65 healthy controls that were age and sex-matched were studied. Patients with extra-hepatic malignancies were excluded. The serum levels of AFP and DCP were determined using the enzyme-linked immunoassay (ELISA) technique. A detailed questionnaire was used to document the socio-demographic characteristics, clinical features as well as results of laboratory/radiologic parameters. Percutaneous liver biopsy was carried out on patients that were fit. Test of association between categorical variables was carried out using the Chi-Square Test. The sensitivity, specificity, positive and negative predictive values of the two tumor markers were determined by the area under curve (AUC) at various cut-off levels using the receiver operating characteristic (ROC) curve analysis. Statistical significance was set at p value < 0.05. AFP Quantitative test kit (alfabeto-RiakiDainabot Radioisotope laboratory, Japan) and DCP Qualitative test kit ( EiTest MONO P-II kit) were used to assay AFP and DCP respectively. Liver biopsy needle (Menghini needle) was used to carry out liver biopsy. Results : Using a cut-off of 400 ng/ml, the sensitivity of serum AFP for diagnosing HCC was 51.3%. The specificity of AFP at the same cut-off was 87.8%. The positive and negative predictive values were 92.8% and 49.3% respectively. Using a cut-off of 7.5 ng/ml, the sensitivity of serum DCP for diagnosing HCC was 57.1%. The specificity of DCP at the same cut-off was 63.4%. The positive and negative predictive values were 76.2% and 41.9% respectively while the accuracy was 59.2%. The diagnostic accuracy of combined serum AFP and DCP for diagnosis of HCC in University of Ilorin Teaching Hospital, Ilorin was 64.9%. The sensitivity of combined serum AFP and DCP for diagnosing HCC was 55.6%. The specificity of combined serum AFP and DCP was 95.6%. The positive and negative predictive values were 96.2% and 52.3% respectively. Conclusion : Combining these two tumour markers does not significantly improve the diagnostic accuracy of HCC and chronic HBV remains a strong aetiological agent of HCC in UITH, Ilorin.