title: The effect of microscopic margin status on survival in adult retroperitoneal soft tissue sarcomas.
abstract: BACKGROUND
  Resection is the primary treatment for retroperitoneal (RP) soft tissue sarcomas (STS). Whether obtaining microscopically negative margins (R0) improves overall survival (OS) over microscopically positive margins (R1) remains unclear.
  
  
  METHODS
  Using the National Cancer Data Base, we identified adult patients diagnosed with RP STS after R0 or R1 resection from 1998 to 2011. We used a multivariable logistic regression model to identify clinicopathologic factors associated with margin status, including radiotherapy receipt. To assess differences in OS, the log-rank test, Cox proportional hazards regression, and propensity score matching were used.
  
  
  RESULTS
  We identified 4015 patients; 2593 (64.6%) underwent R0 resection and 1422 (35.4%) underwent R1 resection. The most common histology was liposarcoma (2,371, 59.1%), median age was 60 years, and median follow up was 67 months. Median OS for R0 vs. R1 patients was 92 and 70 months, respectively (log-rank p < .001). Pre-operative RT was associated with increased probability of R0 resection (68.0% vs. 57.2%, p = .012). Multivariable regression showed R0 vs. R1 resection (HR 0.70, 95% CI 0.60-0.81, p < .001) was associated with improved survival, a finding confirmed on propensity score matching. Other significant predictors of OS included low tumor grade, younger age, smaller tumor size, liposarcoma histology, and receipt of RT (HR 0.81, 95% CI 0.70-0.93, p = .016).
  
  
  CONCLUSIONS
  Patients who undergo R0 resection for RP STS appear to experience superior OS compared with patients who had R1 resections.
authors.affiliation: Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Stahl
authors.affiliation: Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: C D
authors.initials: CD
authors.lastname: Corso
authors.affiliation: Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: H S
authors.initials: HS
authors.lastname: Park
authors.affiliation: Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: An
authors.affiliation: Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: C E
authors.initials: CE
authors.lastname: Rutter
authors.affiliation: Department of Surgery, Section of Surgical Oncology, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: D
authors.initials: D
authors.lastname: Han
authors.affiliation: Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, USA. Electronic address: Kenneth.roberts@yale.edu.
authors.forename: K B
authors.initials: KB
authors.lastname: Roberts
mesh_terms: D000328:Adult; D000368:Aged; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D057216:Propensity Score; D012042:Registries; D012186:Retroperitoneal Neoplasms / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery*; D012189:Retrospective Studies; D012509:Sarcoma / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery*; D015996:Survival Rate; D014481:United States
keywords: R0; Radiation; Resection margin; Retroperitoneal soft tissue sarcoma