Treatment of children over the age of one year with unresectable localised neuroblastoma without MYCN amplification: results of the SIOPEN study.

BACKGROUND In children older than 1 year with localised unresectable neuroblastoma (NB), treatment strategies are heterogeneous according to the national groups. The objective of this phase III non-randomised study was to evaluate the efficacy of conventional chemotherapy followed by surgery. PATIENTS AND METHODS In the presence of surgical risk factors (SRF), six courses of chemotherapy alternating Carboplatin-Etoposide and Vincristin-Cyclophosphamide-Doxorubicin were given, and surgical resection was attempted after four. Survival analyses were performed using an intention-to-treat approach. The main objective was to achieve a 5-year survival over 80%. RESULTS Out of 191 registered children, 160 were evaluable. There were 62.5% older than 18 months and 52.5% had unfavourable histology according to International Neuroblastoma Pathology Classification (INPC). Chemotherapy reduced the number of SRFs by one third. Delayed surgery was attempted in 86.3% of patients and was complete or nearly complete in 74%. The 5-year EFS and OS were 76.4% and 87.6% respectively, with significant better results for patients younger than 18 months or with favourable histology. CONCLUSION This strategy provides encouraging results in children older than 1 year or 12 months with localised unresectable NB without MYCN amplification. However, in children older than 18 months and with unfavourable histology, additional treatment is recommended.