High Dose Thiotepa with Autologous Stem Cell Transplantation in Children over 3 Years with High-Risk Medulloblastoma: Retrospective Cohort Study

Background. Despite current treatment regimens prognosis for high-risk medulloblastoma (MB) is still unfavorable. High dose chemotherapy (HDCT) with autologous stem cell transplantation (ASCT) may improve results.Objective. Our aim was to evaluate the outcomes in children over 3 years with high-risk MB who underwent high dose chemotherapy with thiotepa and ASCT.Methods. We investigated the therapy results in 23 children older than 3 years who received treatment at Russian Cancer Research Centre (Moscow) between January 2013 and December 2017. At consolidation stage they received tandem thiotepa at a dose 300 mg/m2 days -4, -3 and carboplatin at a dose 510 mg/m2 days -4, -3 followed by ASCT. 3 patients failed to undergo the second HDCT course for severe toxic complications.Results. As a result of treatment, 14 patients (60.9%) achieved complete remission, 9 patients (39.2%) had partial response. Treatment mortality rate was 8.6%. The level of 4-year survival was achieved: event-free survival (EFS), overall survival (OS), and disease free survival (DFS) rates were 59%±14%, 68.9%±12.3%, and 69.2%±15.6%, respectively. The worst results were registered in patients with metastatic tumor: 4-year EFS was 64.3%±12% versus patients with M0 stage - 80%±8.9%. Conclusion: Presented intensive treatment with moderate toxicity improves outcomes in poor prognosis patients over 3 years.