title: Initial tumor size predicts histologic response and survival in localized osteosarcoma patients.
abstract: BACKGROUND
  To evaluate the correlation between histologic response and size parameters, and to analyze the prognostic importance of size parameters on metastasis-free survival in localized osteosarcoma patients.
  
  
  METHODS
  We retrospectively reviewed 331 patients with stage II osteosarcoma treated with surgery and chemotherapy. The tumor size parameters were measured and calculated based on MR images. The mean metastasis-free interval was 77.8 months (range, 3-205 months; median, 67 months).
  
  
  RESULTS
  Tumor size is best defined by relative tumor plane (RTP). Patients with a large tumor (RTP>27.5 cm2/m2) had a significant correlation with poor histologic response and distal femoral tumor location. The independent prognostic factors for metastasis-free survival were American Joint Committee on Cancer (AJCC) stage, RTP, proximal humerus location, chondroblastic subtype, and poor histologic response.
  
  
  CONCLUSIONS
  The initial tumor size is closely related to histologic response and is an important prognostic factor in osteosarcoma. Tumor size is best represented by AJCC stage and RTP. These parameters may serve as a basis for risk-adapted therapy in combined stratification with histologic response.
authors.affiliation: Department of Pathology, Korea Cancer Center Hospital, Seoul, Korea.
authors.forename: Min Suk
authors.initials: MS
authors.lastname: Kim
authors.forename: Soo-Yong
authors.initials: SY
authors.lastname: Lee
authors.forename: Wan Hyeong
authors.initials: WH
authors.lastname: Cho
authors.forename: Won Seok
authors.initials: WS
authors.lastname: Song
authors.forename: Jae-Soo
authors.initials: JS
authors.lastname: Koh
authors.forename: Jun Ah
authors.initials: JA
authors.lastname: Lee
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Yoo
authors.forename: Dae-Geun
authors.initials: DG
authors.lastname: Jeon
mesh_terms: D000293:Adolescent; D000328:Adult; D001859:Bone Neoplasms / Q000401:mortality* / Q000473:pathology* / Q000628:therapy; D017024:Chemotherapy, Adjuvant; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006811:Humerus; D007867:Leg Bones; D008279:Magnetic Resonance Imaging; D008297:Male; D009362:Neoplasm Metastasis; D012516:Osteosarcoma / Q000401:mortality* / Q000473:pathology* / Q000628:therapy; D012189:Retrospective Studies; D016019:Survival Analysis