This is the first report of the long-term therapeutic results in 22 children more than 1 year old with stage IV neuroblastoma who were treated with autologous peripheral blood stem cell transplantation (PBSCT). The median age of the patients at PBSCT was 4 years (1 to 10 years) and seven of the 17 patients who were evaluated for N-myc amplification were positive. PBSC were collected by a median of four aphereses per patient. The patients underwent PBSCT from 6 to 21 months after the start of therapy (median 10.5 months) at which time 13 patients were in CR, seven were in PR, and two had refractory disease. Multi-drug therapy using the 'high-MEC' regimen consisting of carboplatinum (400 mg/m2) and VP-16 (200 mg/m2) on days -7 to -4, and melphalan (90 mg/m2) on days -3 and -2, was the primary cytoreductive regimen. The median number of infused MNC and CFU-GM was, respectively, 4.3 x 10(8)/kg and 2.4 x 10(5)/kg. After PBSCT, three patients died of regimen-related toxicities and one patient who was transplanted with refractory disease died of disease progression without any benefit from transplantation. Hematological recovery was evaluated in 21 patients, excluding one early death. The median number of days required to achieve an AGC of >0.5 x 10(9)/l and platelet count of >50 x 10(9)/l were, respectively, 11 and 46. Eleven patients relapsed 3 to 50 months after PBSCT, and currently seven patients (5/13 who were transplanted in CR and 2/7 in PR) are surviving disease-free at 52 to 84 months. Although the retrospective nature of this study and several variables prevent a meaningful analysis, the overall results still support the feasibility of developing a prospective study of PBSCT with a larger number of children with high-risk neuroblastoma.