Table 1. Risk Factors Associated With Hepatoblastoma and Hepatocellular Carcinoma continued...
The AFP and beta-hCG tumor markers are very helpful in diagnosis and management of liver tumors. Although AFP is elevated in most children with hepatic malignancy, it is not pathognomonic for a malignant liver tumor. The AFP level can be elevated due to a benign tumor, as well as a malignant solid tumor. AFP is very high in neonates and steadily falls after birth. The half-life of AFP is 5 to 7 days, and by age 1 year, it should be less than 10 ng/ml.
Cure of hepatoblastoma or hepatocellular carcinoma requires gross tumor resection. If a hepatoblastoma is completely removed, the majority of patients survive, but less than one-third of patients have lesions amenable to complete resection at diagnosis. Thus, it is critically important that a child with probable hepatoblastoma be evaluated by a pediatric surgeon who is experienced in the resection of hepatoblastoma in children and has access to a liver transplant program.
Chemotherapy can often decrease the size and extent of hepatoblastoma, allowing complete resection.[10,11,12,42,43] Orthotopic liver transplantation provides an additional treatment option for patients whose tumor remains unresectable after preoperative chemotherapy;[43,44,45] however, the presence of microscopic residual tumor at the surgical margin does not preclude a favorable outcome.[46,47] This may be due to the additional courses of chemotherapy that are administered before or after resection for patients with stage I and pure fetal histology and after resection for all other patients.[10,11,47]
Hepatoblastoma is most often unifocal, and resection is often possible. Hepatocellular carcinoma is often extensively invasive or multicentric, and less than 30% are resectable. Orthotopic liver transplantation has been successful in selected children with hepatocellular carcinoma.
Tumor marker–related factors
Ninety percent of patients with hepatoblastoma and two-thirds of patients with hepatocellular carcinoma have a serum tumor marker, AFP, which parallels disease activity. The level of AFP at diagnosis and rate of decrease in AFP during treatment should be compared with the age-adjusted normal range. Lack of a significant decrease of AFP levels with treatment may predict a poor response to therapy. Absence of elevated AFP levels at diagnosis occurs in a small percentage of children with hepatoblastoma and appears to be associated with very poor prognosis, as well as with the small cell undifferentiated variant of hepatoblastoma. Some of these variants do not express INI1 due to INI1 mutation and may be considered rhabdoid tumors of the liver; all small cell undifferentiated hepatoblastomas should be tested for loss of INI1 expression by immunohistochemistry.[46,49,50,51,52,53]
Beta-hCG levels may also be elevated in children with hepatoblastoma or hepatocellular carcinoma, which may result in isosexual precocity in boys.[54,55] Extremely high levels of beta-hCG are associated with infantile choriocarcinoma of the liver.