Treatment of advanced neuroblastoma with emphasis on intensive induction chemotherapy. A report from the Study Group of Japan. One hundred nine newly treated patients with advanced neuroblastoma were entered in this study between January 1985 and May 1989. The eligible patients included infants younger than 12 months of age with Stage IVA disease (bone cortex, distant lymph node, and/or remote organ metastases) and patients aged 12 months or older with Stage III or IV disease (IVA plus IVB with tumor crossing the mid-line and with metastases confined to bone marrow, liver, and skin). The patients first received six cyclic course of intensive chemotherapy (regimen A1), consisting of cyclophosphamide (1200 mg/m2), vincristine (1.5 mg/m2), tetrahydropyranyl adriamycin (pyrarubicin; 40 mg/m2), and cisplatin (90 mg/m2). Original tumors and the regional lymph node metastases were removed some time during these first six cycles of chemotherapy. The patients were further divided into three groups. Patients in course 1 received alternating treatment by regimen B (cyclophosphamide and ACNU) and intensified regimen A1, and those in course 2 were treated with alternating administration of regimen C (cyclophosphamide and DTIC) and intensified A1. Patients in course 3 were treated with bone marrow transplantation (BMT) preceded by high-dose preconditioning chemotherapy. Survival rates were 77% in Stage III and 54% in Stage IV at 2 years, and 70% in Stage III and 45% in Stage IV at 3 years. The major toxicities encountered were bone marrow suppression with leukocyte counts down to 100/mm3, mild cystitis, and hearing impairment. The 2-year survival rate was 78% in 21 patients who underwent BMT when complete remission was achieved. We concluded that our intensive induction chemotherapy is of significant value in increasing the rate of complete response, and in widening the indications for and achieving improved results of treatment with BMT. 