Eligibility
All patients aged ≤18 years with newly diagnosed primary SYST at SYSUCC between January 2007 and December 2018 were eligible. Initial diagnosis was established on the basis of confirmed histology and AFP exceeding age-related normal range. The staging was performed according to classification system developed by Children’s Oncology Group (Supplement 1). Clinical variables were recorded regarding age, sex, AFP level, stage, metastasis site, primary tumor size, treatment and pathological response. The date of last follow-up was April 18, 2020. In the cohort, initial treatment decision was made according to tumor size, stage and risks by treating physician. The present study was approved by the Ethics Board of the Sun Yat-sen University Cancer Center (SYSUCC, 2020-FXY-115) and conducted in accordance with the Helsinki Declaration.