title: Stereotactic ablative radiotherapy (SABR) for treatment of central and ultra-central lung tumors.
abstract: OBJECTIVE
  Treatment of central and ultra-central lung tumors with stereotactic ablative radiotherapy (SABR) remains controversial due to risks of treatment-related toxicities compared with peripheral tumors. Here we report our institution's experience in treating central and ultra-central lung tumor patients with SABR.
  
  
  METHODS
  We retrospectively reviewed outcomes in 68 patients with single lung tumors, 34 central and 34 peripheral, all treated with SABR consisting of 50 Gy in 4-5 fractions. Tumor centrality was defined per the RTOG 0813 protocol. We defined "ultra-central" tumors as those with GTV directly abutting the central airway.
  
  
  RESULTS
  Median follow-up time was 18.4 months and median overall survival was 38.1 months. Two-year overall survival was similar between ultra-central, central, and peripheral NSCLC (80.0% vs. 63.2% vs. 86.6%, P=0.62), as was 2-year local failure (0% vs. 10.0% vs. 16.3%, P=0.64). Toxicity rates were low and comparable between the three groups, with only two cases of grade 3 toxicity (chest wall pain), and one case of grade 4 toxicity (pneumonitis) observed. Patients with ultra-central tumors experienced no symptomatic toxicities over a median follow-up time of 23.6 months. Dosimetric analysis revealed that RTOG 0813 central airway dose constraints were frequently not achieved in central tumor treatment plans, but this did not correlate with increased toxicity rate.
  
  
  CONCLUSIONS
  Patients with central and ultra-central lung tumors treated with SABR (50 Gy in 4-5 fractions) experienced few toxicities and good outcomes, similar to patients with peripheral lung tumors.
authors.affiliation: Department of Radiation Oncology, Stanford University School of Medicine, 875 Blake Wilbur Drive, Stanford, CA 94305, USA.
authors.forename: Aadel A
authors.initials: AA
authors.lastname: Chaudhuri
authors.affiliation: Department of Radiation Oncology, Stanford University School of Medicine, 875 Blake Wilbur Drive, Stanford, CA 94305, USA.
authors.forename: Chad
authors.initials: C
authors.lastname: Tang
authors.affiliation: Department of Radiation Oncology, Stanford University School of Medicine, 875 Blake Wilbur Drive, Stanford, CA 94305, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Binkley
authors.affiliation: Department of Radiation Oncology, Stanford University School of Medicine, 875 Blake Wilbur Drive, Stanford, CA 94305, USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Jin
authors.affiliation: Department of Radiation Oncology, Stanford University School of Medicine, 875 Blake Wilbur Drive, Stanford, CA 94305, USA.
authors.forename: Jacob F
authors.initials: JF
authors.lastname: Wynne
authors.affiliation: Department of Radiation Oncology, Stanford University School of Medicine, 875 Blake Wilbur Drive, Stanford, CA 94305, USA.
authors.forename: Rie
authors.initials: R
authors.lastname: von Eyben
authors.affiliation: Department of Radiation Oncology, Stanford University School of Medicine, 875 Blake Wilbur Drive, Stanford, CA 94305, USA; Stanford Cancer Institute, Stanford University School of Medicine, 875 Blake Wilbur Drive, Stanford, CA 94305, USA.
authors.forename: Wendy Y
authors.initials: WY
authors.lastname: Hara
authors.affiliation: Department of Radiation Oncology, Stanford University School of Medicine, 875 Blake Wilbur Drive, Stanford, CA 94305, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Trakul
authors.affiliation: Department of Radiation Oncology, Stanford University School of Medicine, 875 Blake Wilbur Drive, Stanford, CA 94305, USA; Stanford Cancer Institute, Stanford University School of Medicine, 875 Blake Wilbur Drive, Stanford, CA 94305, USA. Electronic address: BWLoo@Stanford.edu.
authors.forename: Billy W
authors.initials: BW
authors.lastname: Loo
authors.affiliation: Department of Radiation Oncology, Stanford University School of Medicine, 875 Blake Wilbur Drive, Stanford, CA 94305, USA; Stanford Cancer Institute, Stanford University School of Medicine, 875 Blake Wilbur Drive, Stanford, CA 94305, USA; Institute for Stem Cell Biology & Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA. Electronic address: diehn@Stanford.edu.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Diehn
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000473:pathology; D019583:Dose Fractionation, Radiation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology; D017564:Radiation Pneumonitis / Q000209:etiology*; D011859:Radiography; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects / Q000379:methods*; D012189:Retrospective Studies; D013238:Stereotaxic Techniques; D015996:Survival Rate; D035441:Thoracic Wall / Q000528:radiation effects
keywords: Lung neoplasms; Non-small cell lung cancer; Radiation oncology; Stereotactic ablative radiotherapy; Stereotactic body radiotherapy; Toxicity