[1] Univ Coll Hosp, Dept Oncol, London NW1 2PG, England
[2] Med Res Council Clin Trials Unit, Canc Grp, London, England
[3] European Org Res Treatment Canc Data Ctr, Soft Tissue & Bone Sarcoma Grp, Brussels, Belgium
[4] Tom Baker Canc Clin, Dept Med Oncol, Calgary, AB, Canada
[5] Alder Hey Childrens NHS Fdn Trust, Liverpool, Merseyside, England
[6] Leiden Univ, Med Ctr, Dept Orthopaed Surg, Leiden, Netherlands
[7] Leiden Univ, Med Ctr, Dept Clin Oncol, Leiden, Netherlands
[8] Leiden Univ, Med Ctr, Dept Pathol, Leiden, Netherlands