title: Stereotactic ablative radiotherapy (SABR) for central lung tumors: Plan quality and long-term clinical outcomes.
abstract: OBJECTIVE
  Central lung SABR is less established due to toxicity concerns. We describe plan quality and clinical outcomes for patients treated with VMAT SABR using 8×7.5Gy.
  
  
  METHODS
  We studied 80 consecutive patients with primary NSCLC and PTV ⩽2cm from the proximal bronchial tree (PBT), treated between 2008 and 2013. Dosimetric data were compared with institutional guidelines and study protocols, and long-term clinical outcomes were analyzed.
  
  
  RESULTS
  PTV V95% was 60Gy in 96% of patients. Dmax was ⩾60Gy in 40% of patients for PBT, 26.3% for aorta, 55% for heart, and 1.3% for trachea. Esophageal maximum Dmax was 58Gy. Mean lung V5Gy/V20Gy was 21/8%. 54 patients (68%) exceeded RTOG0813 Dmax for ⩾1 organ-at-risk (OAR), with 27 exceeding PBT Dmax. 5 of 78 patients (6.4%) with adequate follow-up information had grade 3 toxicity. Grade 4 toxicity was not observed. Treatment-related death was considered possible (n=3) or likely (n=3) in 6 patients (7.5%). With median follow-up of 47months, 3-year survival was 53%, compared with 57% for 252 peripheral tumors treated with 3/5-fractions SABR in the same period (p=0.369).
  
  
  CONCLUSIONS
  Although a substantial proportion of central SABR patients received ⩾60Gy to OARs, the 3-year survival was no different from peripheral SABR.
authors.affiliation: Department of Radiation Oncology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Hilâl
authors.initials: H
authors.lastname: Tekatli
authors.affiliation: Department of Radiation Oncology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Suresh
authors.initials: S
authors.lastname: Senan
authors.affiliation: Department of Radiation Oncology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Max
authors.initials: M
authors.lastname: Dahele
authors.affiliation: Department of Radiation Oncology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Slotman
authors.affiliation: Department of Radiation Oncology, VU University Medical Center, Amsterdam, The Netherlands. Electronic address: w.verbakel@vumc.nl.
authors.forename: Wilko F A R
authors.initials: WF
authors.lastname: Verbakel
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods* / Q000592:standards; D016896:Treatment Outcome
keywords: Central lung tumors; Dosimetry; Plan quality; SABR; Toxicity