title: Why do patients with radiation-induced sarcomas have a poor sarcoma-related survival?
abstract: BACKGROUND
  This study aims to provide reasons for the poor sarcoma-related survival in patients with radiation-induced sarcoma (RIS).
  
  
  METHODS
  We performed a case-control study comparing sarcoma-related survival of 98 patients with RIS to that of 239 sporadic high-grade malignant sarcomas.
  
  
  RESULTS
  The cumulative sarcoma-related 5-year survival was 32% (95% confidence interval (CI): 22-42) for patients with RIS vs 51% (95% CI: 44-58) for controls (P<0.001). Female gender, central tumour site and incomplete surgical remission were significantly more frequent among RIS patients than in controls. In multivariate analysis incomplete surgical remission (hazard ratio (HR) 4.48, 95% CI: 3.08-6.52), metastases at presentation (HR 2.93, 95% CI: 1.95-4.41), microscopic tumour necrosis (HR 1.88, 95% CI: 1.27-2.78) and central tumour site (HR 1.71, 95% CI: 1.18-2.47) remained significant adverse prognostic factors, but not sarcoma category (RIS vs sporadic).
  
  
  CONCLUSIONS
  The poor prognosis of RIS patients are not due to the previous radiotherapy per se, but related to the unfavourable factors - central tumour site, incomplete surgical remission, microscopic tumour necrosis and the presence of metastases, the two former factors overrepresented in RIS.
authors.affiliation: Department of Pathology, Postboks 4953, NO-0424 Oslo, Norway. bodil.bjerkehagen@oslo-universitetssykehus.no
authors.forename: B
authors.initials: B
authors.lastname: Bjerkehagen
authors.forename: M C
authors.initials: MC
authors.lastname: Småstuen
authors.forename: K S
authors.initials: KS
authors.lastname: Hall
authors.forename: S
authors.initials: S
authors.lastname: Skjeldal
authors.forename: S
authors.initials: S
authors.lastname: Smeland
authors.forename: S D
authors.initials: SD
authors.lastname: Fosså
mesh_terms: D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009381:Neoplasms, Radiation-Induced / Q000473:pathology*; D011379:Prognosis; D012509:Sarcoma / Q000209:etiology / Q000473:pathology*; D015996:Survival Rate