Granulocyte colony stimulating factor permits dose intensification by interval compression in the treatment of Ewing's sarcomas and soft tissue sarcomas in children

71 children with sarcomas were treated in a prospective pilot study to dete rmine whether granulocyte colony stimulating factor (G-CSF) permits compres sion of the interval between chemotherapy cycles. Patients had Ewing's sarc oma/primitive neuroectodermal tumour (PNET). rhabdomyosarcoma, non-rhabdo s oft tissue sarcomas or other advanced soft tissue tumours. The chemotherapy alternated vincristine-doxorubicin-cyclophosphamide and ifosfamide-etoposi de. with G-CSF between courses. Therapy had two phases: induction (six cycl es) and continuation (six cycles), which included primary tumour treatment with surgery and/or radiation. Chemotherapy cycles began every 14 days, or upon absolute neutrophil count (ANC) and platelet count recovery. The media n chemotherapy cycle interval was 16 (11-48) days in the induction phase, w ith a median average relative dose intensification (ARDI) of 1.27 compared with every-21-day therapy. In the continuation phase, the median cycle inte rval was 21 days, with a median ARDI of 1.10. Radiation therapy prolonged c hemotherapy intervals, whilst erythropoietin shortened them. Toxicity was m odest for such chemotherapy. Event-free survival is comparable with or supe rior to that in recent large studies. G-CSF permits intensification of this regimen through interval compression. The impact of this approach on effic acy remains to be determined in a randomised trial. (C) 2000 Elsevier Scien ce Ltd. AII rights reserved.