Treatment
IREC therapy comprised of irinotecan 100 mg/m2 (2-hour infusion) on days 1 through 3; etoposide 100 mg/m2(2-hour infusion) on days 1 through 3; and carboplatin 80 mg/m2 (2-hour infusion) on days 1 through 3. All patients were admitted to the hospital and underwent intravenous hydration. Trimethoprim-sulfamethoxazole and fluconazole were administered orally for infection prophylaxis. In patients with grade IV neutropenia, prophylactic use of granulocyte colony-stimulating factor (G-CSF) was allowed. Blood transfusions were administered as appropriate with a target of hemoglobin >7 g/dL and platelet count >20 × 109/L. Oral cefpodoxime was administered to prevent the development of diarrhea caused by irinotecan. IREC was administered at 4-week intervals if bone marrow recovery (neutrophil count >0.5 × 109/L and platelet count >100 × 109/L) was achieved. Treatment response was assessed in all patients using the International Neuroblastoma Response Criteria (INRC)11.