title: Lung stereotactic ablative radiotherapy (SABR): dosimetric considerations for chest wall toxicity.
abstract: OBJECTIVE
  To investigate chest wall pain in patients with peripheral early stage lung cancer treated with stereotactic ablative radiotherapy (SABR), and to identify factors predictive of Common Terminology Criteria of Adverse Events Grade 2 + chest wall pain.
  
  
  METHODS
  Patients who received 55 Gy in five fractions were included. A chest wall structure was retrospectively defined on planning scans, and chest wall dosimetry and tumour-related factors recorded. Logistic regression was performed to identify factors predictive of ≥Grade 2 chest wall pain.
  
  
  RESULTS
  182 patients and 187 tumours were included. There were 20 (10.9%) episodes of ≥Grade 2 chest wall pain. Multivariate logistic regression demonstrated that the maximum dose received by 1 cm(3) of chest wall (Dmax1 cm(3)) and tumour size were significant predictors of ≥Grade 2 chest wall pain [Dmax1 cm(3) odds ratio : 1.104, 95% confidence interval : 1.012-1.204, p = 0.025; tumour size (mm) odds ratio : 1.080, 95% confidence interval : 1.026-1.136, p = 0.003]. This model was an adequate fit to the data (Hosmer and Lemeshow test non-significant) and a fair discriminator for chest wall pain (area under receiver-operating characteristic curve: 0.74). Using the multivariate logistic regression model, parameters for Dmax1 cm(3) are provided, which predict <10% and <20% risks of ≥Grade 2 chest wall pain for different tumour sizes.
  
  
  CONCLUSIONS
  Grade 2+ chest wall pain is an uncommon side effect of lung SABR. Larger tumour size and increasing Dmax1 cm(3) are significant predictors of ≥Grade 2 chest wall pain. When planning lung SABR, it is prudent to try to avoid hot volumes in the chest wall, particularly for larger tumours.
  
  
  CONCLUSIONS
  This article demonstrates that Grade 2 or greater chest wall pain following lung SABR is more common when the tumour is larger in size and the Dmax1 cm(3) of the chest wall is higher. When planning lung SABR, the risk of chest wall pain may be reduced if maximum doses are minimized, particularly for larger tumours.
authors.affiliation: 1 Department of Clinical Oncology, St James's Institute of Oncology, Leeds Cancer Centre, Leeds, UK.
authors.forename: Louise
authors.initials: L
authors.lastname: Murray
authors.affiliation: 1 Department of Clinical Oncology, St James's Institute of Oncology, Leeds Cancer Centre, Leeds, UK.
authors.forename: Ebru
authors.initials: E
authors.lastname: Karakaya
authors.affiliation: 2 Clinical Trials Research Unit, Leeds Institute of Clinical Trials Research, University of Leeds, Leeds, UK.
authors.forename: Samantha
authors.initials: S
authors.lastname: Hinsley
authors.affiliation: 3 Department of Medical Physics, St James's Institute of Oncology, Leeds Cancer Centre, Leeds, UK.
authors.forename: Mitchell
authors.initials: M
authors.lastname: Naisbitt
authors.affiliation: 3 Department of Medical Physics, St James's Institute of Oncology, Leeds Cancer Centre, Leeds, UK.
authors.forename: John
authors.initials: J
authors.lastname: Lilley
authors.affiliation: 1 Department of Clinical Oncology, St James's Institute of Oncology, Leeds Cancer Centre, Leeds, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Snee
authors.affiliation: 1 Department of Clinical Oncology, St James's Institute of Oncology, Leeds Cancer Centre, Leeds, UK.
authors.forename: Katy
authors.initials: K
authors.lastname: Clarke
authors.affiliation: 1 Department of Clinical Oncology, St James's Institute of Oncology, Leeds Cancer Centre, Leeds, UK.
authors.forename: Hima B
authors.initials: HB
authors.lastname: Musunuru
authors.affiliation: 1 Department of Clinical Oncology, St James's Institute of Oncology, Leeds Cancer Centre, Leeds, UK.
authors.forename: Satiavani
authors.initials: S
authors.lastname: Ramasamy
authors.affiliation: 1 Department of Clinical Oncology, St James's Institute of Oncology, Leeds Cancer Centre, Leeds, UK.
authors.forename: Rob
authors.initials: R
authors.lastname: Turner
authors.affiliation: 1 Department of Clinical Oncology, St James's Institute of Oncology, Leeds Cancer Centre, Leeds, UK.
authors.forename: Kevin
authors.initials: K
authors.lastname: Franks
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D009364:Neoplasm Recurrence, Local; D010146:Pain / Q000209:etiology*; D010147:Pain Measurement; D016634:Radiosurgery / Q000009:adverse effects*; D011879:Radiotherapy Dosage; D061089:Radiotherapy, Image-Guided; D012189:Retrospective Studies; D015996:Survival Rate; D035441:Thoracic Wall / Q000528:radiation effects*