Validation of the Stratification for Newly Diagnosed Hepatoblastoma: an Analysis from the Children’s Hepatic Tumors International Collaboration (CHIC) Database

Introduction The Children’s Hepatic Tumors International Collaboration (CHIC) previously developed the CHIC hepatoblastoma risk stratification (CHIC-HS) model by analyzing the original CHIC dataset (development set). A validation of the results was planned with data from contemporary trials that were ongoing at the time of the initial analysis. Material and Methods Subsequent analysis was performed on the contemporary trials (validation set) SIOPEL 4, SIOPEL 6, COG AHEP0731, and JPLT 2 (2011-2013 cohort) utilizing the same methodology as in the CHIC-HS development. Results 403 patients were available for analysis for validation of the CHIC-HS model. Clinical characteristics were comparable between the validation and development sets. Event free survival (EFS) was similar in the very low and low-risk CHIC-HS strata in both the development and validation sets. EFS was higher in the intermediate and high-risk strata in the validation set as compared with the development set consistent with improved survival of intermediate-risk patients on AHEP0731 and high-risk patients on SIOPEL 4. Conclusions The four risk groups in the CHIC-HS retain their relevance for risk stratification in this analysis, notwithstanding improved outcomes in patients with higher risk hepatoblastoma; therefore, the CHIC-HS remains a valid model which differentiates patients into statistically distinct risk strata. The model will be further evaluated with data from the current pediatric international hepatic tumors trial (PHITT).