title: Scoring system predictive of survival for patients undergoing stereotactic body radiation therapy for liver tumors.
abstract: BACKGROUND
  Stereotactic body radiation therapy (SBRT) is an emerging treatment option for liver tumors. This study evaluated outcomes after SBRT to identify prognostic variables and to develop a novel scoring system predictive of survival.
  
  
  METHODS
  The medical records of 52 patients with a total of 85 liver lesions treated with SBRT from 2003 to 2010 were retrospectively reviewed. Twenty-four patients had 1 lesion; 27 had 2 or more. Thirteen lesions were primary tumors; 72 were metastases. Fiducials were placed in all patients prior to SBRT. The median prescribed dose was 30 Gy (range, 16 - 50 Gy) in a median of 3 fractions (range, 1-5).
  
  
  RESULTS
  With median follow-up of 11.3 months, median overall survival (OS) was 12.5 months, and 1 year OS was 50.8%. In 42 patients with radiographic follow up, 1 year local control was 74.8%. On univariate analysis, number of lesions (p = 0.0243) and active extralesional disease (p < 0.0001) were predictive of OS; Karnofsky Performance Status (KPS) approached statistical significance (p = 0.0606). A scoring system for predicting survival was developed by allocating 1 point for each of the three following factors: active extralesional disease, 2 or more lesions, and KPS ≤ 80%. Score was associated with OS (p < 0.0001). For scores of 0, 1, 2 and 3, median survival intervals were 34, 12.5, 7.6, and 2.8 months, respectively.
  
  
  CONCLUSIONS
  SBRT offers a safe and feasible treatment option for liver tumors. A prognostic scoring system based on the number of liver lesions, activity of extralesional disease, and KPS predicts survival following SBRT and can be used as a guide for prospective validation and ultimately for treatment decision-making.
authors.affiliation: Department of Radiation Oncolog, Georgetown University Hospital, Lower Level Bles, 3800 Reservoir Road, Georgetown, NW Washington, DC 20007, USA. Marie-Adele.S.Kress@gunet.georgetown.edu
authors.forename: Marie-Adele S
authors.initials: MA
authors.lastname: Kress
authors.forename: Brian T
authors.initials: BT
authors.lastname: Collins
authors.forename: Sean P
authors.initials: SP
authors.lastname: Collins
authors.forename: Anatoly
authors.initials: A
authors.lastname: Dritschilo
authors.forename: Gregory
authors.initials: G
authors.lastname: Gagnon
authors.forename: Keith
authors.initials: K
authors.lastname: Unger
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D017567:Karnofsky Performance Status; D008113:Liver Neoplasms / Q000401:mortality* / Q000532:radiotherapy* / Q000556:secondary; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009362:Neoplasm Metastasis; D011379:Prognosis; D011874:Radiometry; D016634:Radiosurgery / Q000379:methods* / Q000592:standards*; D012189:Retrospective Studies; D016896:Treatment Outcome