High Dose Chemotherapy with Autologous Stem Cell Transplantation in Hepatoblastoma does not Improve Outcome. Results of the GPOH Study HB99

Introduction The purpose of the German HB99 trial (1999-2008) for hepatoblastoma (HB), was primarily to analyse the effect of high dose (HD) chemotherapy with carboplatin/etoposide (CE) in high risk (HR) patients with extended tumors, vessel involvement, extrahepatic tumor or distant metastases. In standard risk (SR) patients the effect of treatment reduction was analysed. Methods HR patients received 2 cycles CE at conventional dose, followed by 2 at HD with subsequent autologous stem cell transplantation before delayed surgery. SR patients received 3-4 cycles of ifosfamide, cisplatin and doxorubicin (IPA) and delayed surgery. Analysis was on an intention to treat basis including resection rate, AFP decline, event free survival (EFS) and overall survival (OS). The patients with HD therapy were additionally analysed on an as treated basis. The results were compared to historical/published data. Results Of the 142 patients, the 5-y OS was 58% for the 57 HR patients and 94% for the 85 SR patients. The AFP decline after 2 cycles CE was >= 50% in > 90% of the patients. 12/18 (67%) patients treated with HD therapy showed an AFP decline after the first cycle (as treated). Tumor resection was possible in 89% of the patients. The median FU was 7.4 years. Late deaths occurred in 4 patients. Conclusion Use of HD chemotherapy for HB did not improve patient outcomes, compared to contemporaneous and more recent trials (SIOPEL 4 trial). Reduction of therapy in SR patients was possible without worsening of results compared to previous trials. The tumor response to CE was good. CE can therefore be considered for relapse patients.