title: Multimodality Treatment of Skull Base Chondrosarcomas: The Role of Histology Specific Treatment Protocols.
abstract: BACKGROUND
  Limited data exist to guide the multimodality management of chondrosarcomas (CSAs) arising in the skull base.
  
  
  OBJECTIVE
  To determine the impact of histological subtype/grade on progression-free survival (PFS) and the indications for surgery, radiation, and chemotherapy based on histology.
  
  
  METHODS
  A retrospective review was performed of 37 patients (conventional type: 81%, mesenchymal: 16.2%, dedifferentiated: 2.7%) treated at The University of Texas M.D. Anderson Cancer Center. Of the conventional subtype, 23% were grade 1, 63% were grade 2, and 14% were grade 3. In addition to surgery, mesenchymal/dedifferentiated CSAs (18% of the cohort) underwent neoadjuvant chemotherapy and 48.6% of the overall cohort received adjuvant radiotherapy. Histological grade/subtype and treatment factors were assessed for impact on median PFS (primary outcome).
  
  
  RESULTS
  Conventional subtype vs mesenchymal/dedifferentiated was positively associated with median PFS (166 vs 24 months, P < .05). Increasing conventional grade inversely correlated with median PFS ( P < .05). Gross total resection positively impacted PFS in conventional CSAs (111.8 vs 42.9 months, P = .201) and mesenchymal/dedifferentiated CSAs (58.2 vs 1.0 month, P < .05). Adjuvant radiotherapy significantly impacted PFS in conventional grades 2 and 3 (182 vs 79 months, P < .05) and a positive trend with mesenchymal/dedifferentiated CSAs (43.5 vs 22.0 months). Chemotherapy improved PFS for mesenchymal/dedifferentiated CSAs (50 vs 9 months, P = .089).
  
  
  CONCLUSIONS
  There is a potential need for histological subtype/grade specific treatment protocols. For conventional CSAs, surgery alone provides optimal results grade 1 CSAs, while resection with adjuvant radiotherapy yields the best outcome for grade 2 and 3 CSAs. Improvements in PFS seen with neoadjuvant therapy in mesenchymal/dedifferentiated CSAs indicate a potential role for systemic therapies. Larger studies are necessary to confirm the proposed treatment protocols.
authors.affiliation: Department of Neurosurgery, The University of Texas M.D. Anderson Cancer Center, Houston, Texas.
authors.forename: Shaan M
authors.initials: SM
authors.lastname: Raza
authors.affiliation: Department of Head and Neck Surgery, The University of Texas M.D. Anderson Cancer Center, Houston, Texas.
authors.forename: Paul W
authors.initials: PW
authors.lastname: Gidley
authors.affiliation: Department of Pathology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas.
authors.forename: Jeanne M
authors.initials: JM
authors.lastname: Meis
authors.affiliation: Department of Radiation Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas.
authors.forename: David R
authors.initials: DR
authors.lastname: Grosshans
authors.affiliation: Department of Pathology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas.
authors.forename: Diana
authors.initials: D
authors.lastname: Bell
authors.affiliation: Department of Neurosurgery, The University of Texas M.D. Anderson Cancer Center, Houston, Texas.
authors.forename: Franco
authors.initials: F
authors.lastname: DeMonte
mesh_terms: D002813:Chondrosarcoma / Q000453:epidemiology / Q000473:pathology / Q000628:therapy; D003131:Combined Modality Therapy / Q000379:methods / Q000706:statistics & numerical data; D018572:Disease-Free Survival; D006801:Humans; D012189:Retrospective Studies; D019292:Skull Base Neoplasms / Q000453:epidemiology / Q000473:pathology / Q000628:therapy
keywords: Chemotherapy; Chondrosarcoma; Malignancy; Oncology; Radiation Therapy; Sarcoma; Skull Base; Surgery