Purpose: To evaluate the safety and efficacy of multimodality treatment with vincristine, actinomycin-D, and cyclophosphamide (VAC) therapy, surgery, and radiotherapy according to the U.S. Intergroup Rhabdomyosarcoma Study IV (IRS-IV), and to establish a central review system and standard treatment for intermediate-risk pediatric rhabdomyosarcoma in Japan. Patients and methods: The JRS-I was a single-arm, phase II trial for intermediate-risk rhabdomyosarcoma treatment with open enrollment from June 2004 to March 2009. Patients received 12 cycles of VAC every 3 weeks for 42 weeks, with local therapy beginning after week 12. The endpoints were progression-free survival (PFS), overall survival (OS), and incidence of hepatic veno-occlusive disease (VOD). Results: Thirty-one eligible patients were enrolled, and at a median follow-up of 5.2 years, the 3-year PFS and OS for patients were 74.2% ± 7.9% (95% CI 55.0%-86.2%) and 90.3% ± 5.3% (95% CI 72.9%-96.8%), respectively. VOD occurred in 3 (8%) of the 40 evaluable patients, but all recovered, and there were no deaths. Conclusion: The VAC regimen for intermediate-risk rhabdomyosarcoma with the first central review system in Japan is safe and feasible, and these findings can be positioned as basic data for improving treatment outcomes in Japan.

Background: In children with intermediate-risk relapsed acute lymphoblastic leukemia (ALL), allogeneic hematopoietic stem cell transplantation (allo-HSCT) has markedly improved the outcome of patients with poor minimal residual disease (MRD) response. However, there is no consensus on the optimal conditioning regimen for allo-HSCT. Procedure: We prospectively analyzed the efficacy and safety of allo-HSCT with a unified conditioning regimen for children with intermediate-risk relapsed ALL, based on MRD in the bone marrow after induction, in the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG) ALL-R08-II nationwide cohort. The conditioning regimen for allo-HSCT comprised total body irradiation (TBI), etoposide (ETP) and cyclophosphamide (CY) (UMIN000002025). Results: Twenty patients with post-induction MRD ≥ 10 −3 and two with MRD that could not be evaluated underwent allo-HSCT. Engraftment was confirmed in all patients. No transplantation-related mortality was observed. The 3-year event-free survival and overall survival after transplantation were 86.4% ± 7.3% and 95.5% ± 4.4%, respectively. Conclusion: Allo-HSCT based on post-induction MRD with TBI + ETP + CY conditioning was highly effective and feasible for Japanese children with intermediate-risk relapsed ALL.