Liver tumors in children

This issue of Hepatoma Research is dedicated to liver tumors in Children, which is a quite rare group of tumors. Although the majority of pediatric liver tumors are malignant (57%), its main contributors, hepatoblastoma (HB) and hepatocellular carcinoma (HCC), only have an incidence of 1.6 per 1 million children, thus comprising 5%-8% of all pediatric solid tumors.

Our goal has been to establish an issue for the journal that gives a state-of-the-art overview of some aspects of the current knowledge within this field. The paper of Armengol et al.^[1] overviews some basic science, bridging molecular biology to the prognosis and treatment of HB. Surgical aspects are described by the literature review of Kościuszko et al.^[2], who give an overview of preoperative planning of liver tumor resections, Hiyama et al.^[3], who describe the consequences of marginal positive resection margins, and Calinescu et al.^[4], who describe the role of liver transplantation in Pediatric HB and HCC. Weeda et al.^[5] give an overview of where we stand with HCC, and Calinescu et al.^[6] describe the surgical perspective of undifferentiated sarcoma of the liver.

The way forward in the approach to rare tumors is an international collaboration. It has been this international cooperation between the four major Pediatric Liver Tumor Study Groups in Europe, the USA, and Japan (SIOPEL/GPOH, COG, and JPLT) that formed the tipping point to create the Children’s Hepatic tumor International Collaborative (CHIC), leading to the establishment of a large international collaborative dataset, the CHIC database^[7]. This database contains such a large data set, that its analysis allowed to establish a new universal risk stratification system for HB^[8]. Concomitant international collaboration of pediatric pathologists made it possible to use the collected data to establish a new international histopathologic consensus classification for pediatric liver tumors as a whole, with particular focus on the histological subtypes of HB^[9,10].

During the same period, advances in chemotherapy options developed, an increased role of liver transplantation for unresectable tumors was established, and a web portal system was created at www.siopel.org for international education, consultation, and collaboration. These achievements are currently further tested and validated in the running Paediatric Hepatic International Tumour Trial (PHITT).

This small collection of papers on this subject invites the interested reader to further explore the existing literature on the achievements in the field of Pediatric Liver Tumors that have been established during the past decades^[11].