title: Radiological and clinical pneumonitis after stereotactic lung radiotherapy: a matched analysis of three-dimensional conformal and volumetric-modulated arc therapy techniques.
abstract: OBJECTIVE
  Lung fibrosis is common after stereotactic body radiotherapy (SBRT) for lung tumors, but the influence of treatment technique on rates of clinical and radiological pneumonitis is not well described. After implementing volumetric modulated arc therapy (RapidArc [RA]; Varian Medical Systems, Palo Alto, CA) for SBRT, we scored the early pulmonary changes seen with arc and conventional three-dimensional SBRT (3D-CRT).
  
  
  METHODS
  Twenty-five SBRT patients treated with RA were matched 1:2 with 50 SBRT patients treated with 3D-CRT. Dose fractionations were based on a risk-adapted strategy. Clinical pneumonitis was scored using Common Terminology Criteria for Adverse Events version 3.0. Acute radiological changes 3 months posttreatment were scored by three blinded observers. Relationships among treatment type, baseline factors, and outcomes were assessed using Spearman's correlation, Cochran-Mantel-Haenszel tests, and logistic regression.
  
  
  RESULTS
  The RA and 3D-CRT groups were well matched. Forty-three patients (57%) had radiological pneumonitis 3 months after treatment. Twenty-eight patients (37%) had computed tomography (CT) findings of patchy or diffuse consolidation, and 15 patients (20%) had ground-glass opacities only. Clinical pneumonitis was uncommon, and no differences were seen between 3D-CRT vs. RA patients in rates of grade 2/3 clinical pneumonitis (6% vs. 4%, respectively; p = 0.99), moderate/severe radiological changes (24% vs. 36%, respectively, p = 0.28), or patterns of CT changes (p = 0.47). Radiological severity scores were associated with larger planning target volumes (p = 0.09) and extended fractionation (p = 0.03).
  
  
  CONCLUSIONS
  Radiological changes after lung SBRT are common with both approaches, but no differences in early clinical or radiological findings were observed after RA. Longer follow-up will be required to exclude late changes.
authors.affiliation: Department of Radiation Oncology, VU Medical Center, Amsterdam, The Netherlands. d.palma@vumc.nl
authors.forename: David A
authors.initials: DA
authors.lastname: Palma
authors.forename: Suresh
authors.initials: S
authors.lastname: Senan
authors.forename: Cornelis J A
authors.initials: CJ
authors.lastname: Haasbeek
authors.forename: Wilko F A R
authors.initials: WF
authors.lastname: Verbakel
authors.forename: Andrew
authors.initials: A
authors.lastname: Vincent
authors.forename: Frank
authors.initials: F
authors.lastname: Lagerwaard
mesh_terms: D000368:Aged; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000532:radiotherapy* / Q000601:surgery*; D008297:Male; D016555:Matched-Pair Analysis; D011014:Pneumonia / Q000000981:diagnostic imaging*; D017564:Radiation Pneumonitis / Q000000981:diagnostic imaging*; D016634:Radiosurgery / Q000009:adverse effects* / Q000379:methods; D011880:Radiotherapy Planning, Computer-Assisted; D020266:Radiotherapy, Conformal / Q000009:adverse effects* / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects / Q000379:methods; D014057:Tomography, X-Ray Computed