Anti-alpha-fetoprotein imaging is useful for staging hepatoblastoma

Liver tumors in children

Malignant liver tumors account for slightly >1% of all pediatric malignancies, with roughly 150 new cases of liver tumors diagnosed in the U.S. annually. The embryonal tumor, hepatoblastoma, accounts for two thirds of malignant liver tumors in children. Other liver malignancies in children include hepatocellular carcinoma, sarcomas, germ cell tumors, and rhabdoid tumors. Benign tumors of the liver in children include vascular tumors, hamartomas, and adenomas. There is an apparent increase in the incidence of hepatoblastoma with perinatal exposures and decreased premature infant mortality as postulated causes for this increased risk. The known causes and associations of liver tumors in children as well as the approaches to diagnosis and treatment of children are discussed in this review article.

Radiological staging in children with hepatoblastoma

Hepatoblastoma is the most common malignant liver tumour of childhood. Accurate radiological staging is very important, especially in children who are treated according to the protocols of the International Childhood Liver Tumor Strategy Group (SIOPEL). These protocols use risk stratification, based almost entirely on imaging findings, to minimize the treatment for localized tumours and to intensify treatment for extensive tumours and those with extrahepatic spread.

Positron emission tomography in recurrent hepatoblastoma

Early detection of recurrent hepatoblastoma is not always possible with conventional imaging methods such as computed tomography (CT) and magnetic resonance imaging (MRI). This article describes three cases of recurrent hepatoblastoma in which positron emission tomography (PET) using F(18)-fluoro-deoxy-glucose (FDG-PET) was used to locate the site of recurrence. In the first two patients, FDG-PET accurately located recurrent disease where it was not detected by conventional imaging modalities, including CT and MRI. In the third patient, FDG-PET imaging also located the recurrent disease in an MRI-identified adrenal metastasis. The technique of "coregistration" using PET with CT and MRI scans was used in the cases described. This improves the anatomical localization of metabolically active sites and was particularly useful for determining the surgical approach. The difficulties of conventional imaging in locating early tumor recurrence or metastatic disease in hepatoblastoma make FDG-PET imaging an important investigation that may impact patient management.

Clinical use of tumor markers in childhood malignancies

Tumor markers are developmentally regulated proteins or carbohydrate molecules, which are expressed in specific tissues in the fetus during certain developmental periods. With malignant transformation, these molecules are reexpressed in neoplastic tissues. Some developmental or metabolic disorders can also lead to the expression of tumor marker genes, hereditary tyrosinaemia and ataxia teleangiectasia associating with elevated serum alpha-fetoprotein are examples of such conditions. In pediatric malignancies, the most common markers in clinical use are alpha-fetoprotein in liver and yolk sac tumors, chorionic gonadotropin in germ cell tumors, and catecholamines and neuron specific enolase in neuroblastoma. Several other molecules including carbohydrate antigens CA 19-9 and CA 125 may also have a role in the diagnosis and follow-up of distinct types of childhood malignancies. The non-specificity of several markers, such as tissue polypeptide antigen and sialic acid, greatly hampers their clinical use. In this review we will discuss the biology and current knowledge on the use of serum and urine tumor markers. We also highlight the putative future use of these molecules in cancer diagnosis and therapy, including the use of monoclonal antibodies directed against these antigens.