Treatment algorithm
All patients received neoadjuvant chemotherapy of C5V regimen (cisplatin + vincristine + 5-fluorouracil) according to the treatment protocol of Children Oncology Group (COG). Tumor response and the possibility of resection were evaluated every 2 cycles after chemotherapy with a maximum of 6 cycles. The choice of surgical procedures was performed according to the number of sectors and the hepatic vessels involved. Standard hepatic trisectionectomy was performed for patients with three lobes involved; extended hepatectomy was performed for patients with half liver and one liver segment involved; mesohepatectomy was performed for patients with central hepatoblastoma; irregular hepatectomy was performed for patients with multiple liver segments involved; associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) was performed for patients with less than 40% residual liver after hepatic trisectionectomy or irregular hepatectomy; if the above-mentioned operation is still unable to remove the tumor, liver transplantation would be recommended. Adjuvant chemotherapy was started 3 weeks after operation and stopped after 2 times of normal AFP.
Follow up and statistics
The end point of follow-up was January 2020. Those who have died are complete data, and those who are still alive or lost are censored data. Data analysis was performed by using SPSS18.0 software. The survival rate was analyzed by Kaplan Meier method and the estimates of both the 5-year EFS and OS are given with 95% confidence intervals (CIs). The continuous data are summarized with the median and range or the interquartile range. P < 0.05 was considered as statistically significant.