Successful Treatment of Refractory or Relapsed Hepatoblastoma With Autologous Hematopoietic Stem Cell Transplantation in Children

Background: The standard-risk hepatoblastoma has a good prognosis in children; however, refractory or relapsed (R/R) hepatoblastoma has a poor prognosis and high mortality rate. This study aimed to demonstrate the efficacy of high-dose chemotherapy and autologous hematopoietic stem cell transplantation (HSCT) rescue in pediatric patients with R/R hepatoblastoma. Methods: We retrospectively analyzed 6 pediatric patients with R/R hepatoblastoma who underwent autologous HSCT. The MEC conditioning regimen was used for all patients, comprising melphalan 140 mg/m²/day intravenously (IV) on day 7 and 70 mg/m² on day 6, etoposide 200 mg/m² IV on days 5 to 8, and carboplatin 400 mg/m² IV on days 5 to 8. One patient received a TopoThioCarbo regimen, comprising topotecan 2 mg/m²/day IV on days 4 to 8, thiotepa 300 mg/m²/day IV on days 6 to 8, and carboplatin 500 mg/m²/day IV on days 3 to 5, as the conditioning regimen for the first transplantation. This was followed by salvage chemotherapy for relapse, and the second transplantation was performed using MEC as the conditioning regimen. Results: We report the retrospective results of 6 patients with a median age of 1.8 (range 0.4 to 10.2) years who had R/R hepatoblastoma and underwent autologous HSCT. The median follow-up period was 58 (range 28 to 113) months after diagnosis. The median stage at diagnosis was 2.0 (range 2 to 4). Two patients had lung metastases during diagnosis. The median initial alpha-fetoprotein level was 292,888 (range 28,831 to 2,406,942) ng/mL, and the median number of chemotherapy lines before autologous HSCT was 3.5 (range 2 to 7). The disease status before HSCT was complete remission (CR) for all patients. The engraftment rate was 100%. No treatment-related mortality was reported. The 3-year event-free survival and overall survival rates were 83.3% and 100%, respectively. One patient relapsed after the second HSCT and achieved CR after salvage chemotherapy. Conclusion: This study suggests autologous HSCT as an effective treatment in pediatric patients with R/R hepatoblastoma. Nevertheless, future large-scale prospective studies are warranted.