title: Mesenchymal chondrosarcoma of soft tissues and bone in children, adolescents, and young adults: experiences of the CWS and COSS study groups.
abstract: BACKGROUND
  Mesenchymal chondrosarcoma (MCS) is a rare tumor with a strong tendency toward late recurrences leading to reported 10-year survival rates below 50%. The recommended treatment is resection with wide margins; the effectiveness of chemo- and radiotherapy remain poorly defined. As reports about MCS in young patients are scarce, treatment and outcomes of children/adolescents/young adults in the CWS and COSS studies were investigated.
  
  
  METHODS
  Since 1977, 15 of >7000 CWS and COSS patients <or=25 years had a confirmed diagnosis of MCS.
  
  
  RESULTS
  The median age was 16.6 (range, 1-25) and median follow-up 9.6 years (range, 1-22). Four MCS were osseous and 11 extraosseous. All but 1 patient had nonmetastatic disease. Tumor sites were head/neck (n = 6), paravertebral (n = 3), pelvis (n = 3), limbs (n = 2), and kidney (n = 1). All tumors were resected, but only 8 completely. Thirteen individuals received chemotherapy, 6 were irradiated. Actuarial 10-year event-free and overall survival rates were 53% and 67%, respectively. Four recurrences occurred, all within 4 years from diagnosis (3 local, 1 combined; 2 of these in irradiated patients). One of these patients survived after surgery and radiation for local recurrence. Seven of 8 patients whose tumors were completely resected during primary treatment, but only 4 of 7 patients with incomplete surgery survived disease-free.
  
  
  CONCLUSIONS
  This series of 15 MCS differs from others: the median age was young, most tumors were extraosseous, most patients received chemotherapy, and the outcome was better than published. Despite long-term follow-up, characteristic late metastatic recurrences were not observed. Treating MCS according to standard multimodal soft tissue/bone sarcoma regimens is proposed.
authors.affiliation: Pediatrics 5 - Oncology, Hematology, Immunology, Olgahospital, Klinikum Stuttgart, Stuttgart, Germany. tobias.dantonello@olgahospital-stuttgart.de
authors.forename: Tobias M
authors.initials: TM
authors.lastname: Dantonello
authors.forename: Christoph
authors.initials: C
authors.lastname: Int-Veen
authors.forename: Ivo
authors.initials: I
authors.lastname: Leuschner
authors.forename: Andreas
authors.initials: A
authors.lastname: Schuck
authors.forename: Rhoikos
authors.initials: R
authors.lastname: Furtwaengler
authors.forename: Alexander
authors.initials: A
authors.lastname: Claviez
authors.forename: Dominik T
authors.initials: DT
authors.lastname: Schneider
authors.forename: Thomas
authors.initials: T
authors.lastname: Klingebiel
authors.forename: Stefan S
authors.initials: SS
authors.lastname: Bielack
authors.forename: Ewa
authors.initials: E
authors.lastname: Koscielniak
mesh_terms: D000293:Adolescent; D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001859:Bone Neoplasms / Q000473:pathology* / Q000628:therapy; D002648:Child; D002675:Child, Preschool; D018211:Chondrosarcoma, Mesenchymal / Q000473:pathology* / Q000628:therapy; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D009367:Neoplasm Staging; D011446:Prospective Studies; D011879:Radiotherapy Dosage; D012983:Soft Tissue Neoplasms / Q000473:pathology* / Q000628:therapy; D015996:Survival Rate; D016896:Treatment Outcome