title: Obesity increases the risk of chest wall pain from thoracic stereotactic body radiation therapy.
abstract: OBJECTIVE
  Stereotactic body radiation therapy (SBRT) is increasingly being used to treat thoracic tumors. We attempted here to identify dose-volume parameters that predict chest wall toxicity (pain and skin reactions) in patients receiving thoracic SBRT.
  
  
  METHODS
  We screened a database of patients treated with SBRT between August 2004 and August 2008 to find patients with pulmonary tumors within 2.5 cm of the chest wall. All patients received a total dose of 50 Gy in four daily 12.5-Gy fractions. Toxicity was scored according to the NCI-CTCAE V3.0.
  
  
  RESULTS
  Of 360 patients in the database, 265 (268 tumors) had tumors within <2.5 cm of the chest wall; 104 (39%) developed skin toxicity (any grade); 14 (5%) developed acute pain (any grade), and 45 (17%) developed chronic pain (Grade 1 in 22 cases [49%] and Grade 2 or 3 in 23 cases [51%]). Both skin toxicity and chest wall pain were associated with the V30, or volume of the chest wall receiving 30 Gy. Body mass index (BMI) was also strongly associated with the development of chest pain: patients with BMI≥29 had almost twice the risk of chronic pain (p=0.03). Among patients with BMI>29, diabetes mellitus was a significant contributing factor to the development of chest pain.
  
  
  CONCLUSIONS
  Safe use of SBRT with 50 Gy in four fractions for lesions close to the chest wall requires consideration of the chest wall volume receiving 30 Gy and the patient's BMI and diabetic state.
authors.affiliation: Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA. jwelsh@mdanderson.org
authors.forename: James
authors.initials: J
authors.lastname: Welsh
authors.forename: Jimmy
authors.initials: J
authors.lastname: Thomas
authors.forename: Deep
authors.initials: D
authors.lastname: Shah
authors.forename: Pamela K
authors.initials: PK
authors.lastname: Allen
authors.forename: Xiong
authors.initials: X
authors.lastname: Wei
authors.forename: Kevin
authors.initials: K
authors.lastname: Mitchell
authors.forename: Song
authors.initials: S
authors.lastname: Gao
authors.forename: Peter
authors.initials: P
authors.lastname: Balter
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Komaki
authors.forename: Joe Y
authors.initials: JY
authors.lastname: Chang
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D002637:Chest Pain / Q000209:etiology*; D002908:Chronic Disease; D048909:Diabetes Complications / Q000209:etiology; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D011855:Radiodermatitis / Q000209:etiology*; D016634:Radiosurgery / Q000009:adverse effects*; D012044:Regression Analysis; D035441:Thoracic Wall / Q000528:radiation effects*; D047368:Tumor Burden