Treatment of children with very low-risk hepatoblastoma according to the Children’s Hepatic tumors International Collaboration classification: a series of clinical observations
Authors: Pimenov R. I. , Kerimov P. A. , Kazantsev A. P. , Rubanskaya M. V. , Rubanskiy M. A. , Blisnyukov O. P. , Mikhailova E. V. , Mikhailova S. N. , Nikulina A. L. , Malakhova A. A. , Sagoyan G. B. , Kapkova O. A. , Rybakova D. V. , Varfolomeeva S. R. , Polyakov V. G. 
Published: March 2020

Relevance. The success of treatment of children with hepatoblastoma (HB) is associated primarily with the optimization of diagnostic and therapeutic strategies. The introduction of a system of therapeutic definition of a risk group developed by the International Society for the Study of Liver Tumors in Children’s Hepatic tumors International Collaboration (CHIC) in patients with HB allows for effective risk stratification. Patients of the very low-risk group have a favorable prognosis and, unlike patients of other groups, they can perform surgery at the 1st stage, and children from the very low-risk group with a “pure” fetal version of the morphological structure of the tumor can be cured without chemotherapy – only by surgical method. This article presents an analysis of a series of observations of children with HB very low-risk.

Methods and patients. A retrospective analysis of the data of 138 patients who received treatment at the Research Institute of Pediatric Oncology and Hematology of N.N. Blokhin National Medical Research Centre of Oncology of the Ministry of Health of Russia from January 2006 to February 2018, all patients underwent examination in the following volume: computed tomography (CT) of the chest, ultrasound of the abdominal cavity and retroperitoneal space, CT and/or magnetic resonance imaging of the abdominal cavity with contrast enhancement. Serum levels of human chorionic gonadotropin and alpha-fetoprotein (AFP) were measured. The prevalence of tumor lesions was retrospectively evaluated using the PRETEXT system (Pre-Treatment Extent of Disease, assessment of the prevalence of the tumor process before treatment, 2017 version). Based on the data obtained, 18 (13 %) patients with hypertension were identified in the very low-risk group using the CHIC stratification system. Of 18 (100 %) patients of the very low-risk group, 8 (44.4 %) received therapy in the interval from January 2006 to October 2010 according to the treatment protocols of the SIOPEL group. The treatment included a combination of neoadjuvant chemotherapy with delayed surgery and adjuvant chemotherapy. Since November 2010, the Research Institute of Pediatric Oncology and Hematology adopted a protocol for the treatment of children with hypertension, suggesting the possibility of performing surgical treatment at the 1 st stage in patients with a localized stage of the disease with the spread of PRETEXT I/II. From December 2010 to November 2018, 10 (55.6 %) patients from the very low-risk group were operated on at the 1 st stage. A tumor biopsy was not performed before the intervention. After a histological examination, 4 (22.2 %) patients had an epithelial variant of the structure of HB that did not meet the criteria of a “pure” fetal variant. He was given adjuvant chemotherapy according to the SIOPEL protocol. And in 6 (33.3 %) patients, according to the results of a morphological study, the HB structure variant was interpreted as a “pure” fetal variant. Further therapy in this group of patients was not performed. The analysis of the results of treatment of these 6 patients without the use of chemotherapy is presented in our article.

Results. The average age of patients is 3.7 (1–6) years, the median is 3.7 ± 2.0. Boys/girls – 4:2. In all cases, there was an asymptomatic course of the disease, a neoplasm was detected by chance during an ultrasound scan. All children had an elevated AFP level in the range of 95.2–695 (286.0 ± 116.8) IU/ml. Distribution according to PRETEXT I/II – 2 (33.3 %) and 4 (66.7 %) patients, respectively. Patients did not have additional PRETEXT criteria and metastases. Surgical treatment was performed by the laparoscopic method in 2 of 6 patients. Scope of operation: right-sided hemihepatectomy – 3, left-sided – 1, bisegmentectomy – 1, atypical resection – 1. Lymphatic dissection in the area of the hepatoduodenal ligament was not performed. There were no complications of treatment and repeated surgical interventions. The radicalness of the intervention in the volume of R0 was confirmed by histological examination in all patients. Morphological examination in all cases revealed a “pure” fetal version of the structure of the tumor. All patients are alive without signs of relapse at follow-up periods of 14.7 to 59.2 (32.0 ± 18.7) months.

Conclusion. Using the system of therapeutic stratification into risk groups CHIC allows you to effectively distinguish patients with very low-risk groups, and for some children with a “pure” fetal version of the histological structure of the tumor, only the surgical approach can be used for treatment. At the same time, the short observation period for the patients and their small number do not allow us to draw final conclusions and dictate the need for a multicenter study. It should be noted that this cohort of patients requires careful observance of the post-therapeutic observation algorithm.