title: Clinical outcome and predictors of survival and pneumonitis after stereotactic ablative radiotherapy for stage I non-small cell lung cancer.
abstract: BACKGROUND
  Stereotactic ablative radiotherapy (SABR) can achieve excellent local control rates in early-stage non-small cell lung cancer (NSCLC) and has emerged as a standard treatment option for patients who cannot undergo surgery or those with isolated recurrences. However, factors that may predict toxicity or survival are largely unknown. We sought here to identify predictors of survival and pneumonitis after SABR for NSCLC in a relatively large single-institution series.
  
  
  METHODS
  Subjects were 130 patients with stage I NSCLC treated with four-dimensional computed tomography (4D CT) -planned, on-board volumetric image-guided SABR to 50 Gy in 4 fractions. Disease was staged by positron emission tomography/computed tomography (PET/CT) and scans were obtained again at the second follow-up after SABR.
  
  
  RESULTS
  At a median follow-up time of 26 months, the 2-year local control rate was 98.5%. The median overall survival (OS) time was 60 months, and OS rates were 93.0% at 1 year, 78.2% at 2 years, and 65.3% at 3 years. No patient experienced grade 4-5 toxicity; 15 had radiation pneumonitis (12 [9.3%] grade 2 and 3 [2.3%] grade 3). Performance status, standardized uptake value (SUV)max on staging PET/CT, tumor histology, and disease operability were associated with OS on univariate analysis, but only staging SUV(max) was independently predictive on multivariate analysis (P = 0.034). Dosimetric factors were associated with radiation pneumonitis on univariate analysis, but only mean ipsilateral lung dose ≥ 9.14 Gy was significant on multivariate analysis (P = 0.005).
  
  
  CONCLUSIONS
  OS and radiation pneumonitis after SABR for stage I NSCLC can be predicted by staging PET SUV(max) and ipsilateral mean lung dose, respectively.
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd,, Houston, TX, USA. jychang@mdanderson.org
authors.forename: Joe Y
authors.initials: JY
authors.lastname: Chang
authors.forename: Hui
authors.initials: H
authors.lastname: Liu
authors.forename: Peter
authors.initials: P
authors.lastname: Balter
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Komaki
authors.forename: Zhongxing
authors.initials: Z
authors.lastname: Liao
authors.forename: James
authors.initials: J
authors.lastname: Welsh
authors.forename: Reza J
authors.initials: RJ
authors.lastname: Mehran
authors.forename: Jack A
authors.initials: JA
authors.lastname: Roth
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Swisher
mesh_terms: D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D017564:Radiation Pneumonitis / Q000209:etiology*; D016634:Radiosurgery / Q000009:adverse effects; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome