Structural Liver Disease
Hepatoblastoma is considered to be the most common type of malignant paediatric liver tumour. For instance in a small country as the Netherlands with 17 million inhabitants, this accounts for up to 6 newly diagnosed patients per year. Furthermore, hepatoblastoma is the third most common abdominal neoplasm in children after neuroblastoma and nephroblastoma. Hepatoblastomas commonly occur as a single mass and more often in the right lobe of the liver, in 55-60 percent of the cases.
Medical conditions of children involving the liver are rare and complex at the same time. Paediatric liver tumours are extremely rare in the western world, with an incidence of one per 0.67 million in children (<18 years old). Around 60 percent of liver tumours have a malignant character. C amounts to about 37 percent of all diagnosed paediatric liver tumours, approximately one per 1-1,5 million children. It is more common at a younger children with 10 percent of cases at a neonatal age. Tumour occurrence at an age older than 8 years is associated with a worse prognosis.
Hepatoblastomas commonly occur as a single mass and more often in the right lobe of the liver, in 55-60 percent of the cases. It is more common at a younger children with 10 percent of cases at a neonatal age.
Ultrasound guided sampling of the tumour via biopsy is crucial in confirmation of the diagnosis. Serum alpha-fetoprotein (AFP) is the most important laboratory marker for hepatoblastoma, and remains the key to detect malignant change, response to the treatment, and relapse. Tumour occurrence at an age older than 8 years is associated with a worse prognosis. The syndrom of Beckwith-Wiedemann and of familial adenomatous polyposis (FAP) is associated with hepatoblastoma
The PREtreatment Extent of Tumor system (PRETEXT-system) is a method to standardize the imaging evaluation for patients with hepatoblastoma prior to treatment. The PRETEXT-group, ranging from I to IV, can be calculated by determining the number of tumour-adjacent sections that would have to be resected to completely remove the tumour. The hepatic veins and portal veins divide the liver into its four sections: left lateral section (segment 2 and 3), left medial section (segment 4a and 4b), right anterior section (segment 5 and 8) and right posterior section (segment 6 and 7), segment 1, the caudate lobe, is not included in the PRETEXT-system. The PRETEXT-system is also indicative of a child’s prognosis. The Children’s Oncology Group (COG) INT0098 reports survival rates of 89, 85, 72 and 3 percent in PRETEXT I-IV respectively.
The cornerstone of successful treatment of children with hepatoblastoma is surgical resection, typically preceded by neo-adjuvant chemotherapy. Tumour resection is either accomplished with a partial liver resection or with total hepatectomy followed by orthotopic liver transplantation. Although it has been technically feasible in some locally advanced cases to obtain disease clearance with hepatic resection, the recommendation remains to transplant any patient presenting with extensive multifocal bilobar disease. Advancements in neoadjuvant therapy, specifically the implementation of cisplatin-based regimens, have allowed approximately 50–85 percent of originally unresectable tumours to become amenable to resection.
Children who underwent resection, either with a transplantation or a partial resection, generally have a good prognosis, with 90 percent 5-year survival for stage I-III tumours. There is no long-term survival of patients with non-resectable hepatoblastoma. The care for children with a hepatic malignancy is complex and should be discussed within a dedicated team with previous experience in these complex decisions. In a study performed by one of the ERN member centres concerning hepatoblastoma patients, centralization of care was suggestive of a decrease in the amount and severity of complications of partial hepatectomy.