Treatment
All 41 patients underwent intensive multidrug induction chemotherapy in median 5 cycles (range = 4−7 cycles). A sufficient amount of peripheral blood stem cell grafts were collected from 39 patients during chemotherapy, while auto-bone marrow grafts were collected from 2 patients because of insufficient peripheral stem cell collection. Resection of the primary tumor was performed in 11 patients before HDC. Radiation therapy for the primary site was administered in 29 patients. Before HDC, of the 41 patients, 14 (33%) (MYCN -amplified high-risk neuroblastoma, 11; MYCN -non-amplified high-risk neuroblastoma, 3; P = 0.051) showed complete response or very good partial response (CR/VGPR). Of 26 patients, 7 (27%) who did not undergo resection before HDC showed CR/VGPR. Of 41 patients, 15 (37%) received a reduced dose of thiotepa and melphalan as HDC because of renal function deterioration. In addition, 24 (59%) patients whose guardians requested off-label use underwent retinoic acid therapy, and 8 (20%) patients with poor response after treatment underwent a second SCT using cord blood stem cells, expecting immunological effects. No patients underwent anti-GD2 antibody immunotherapy.