title: Cardiac comorbidity is an independent risk factor for radiation-induced lung toxicity in lung cancer patients.
abstract: OBJECTIVE
  To test the hypothesis that cardiac comorbidity before the start of radiotherapy (RT) is associated with an increased risk of radiation-induced lung toxicity (RILT) in lung cancer patients.
  
  
  METHODS
  A retrospective analysis was performed of a prospective cohort of 259 patients with locoregional lung cancer treated with definitive radio(chemo)therapy between 2007 and 2011 (ClinicalTrials.gov Identifiers: NCT00572325 and NCT00573040). We defined RILT as dyspnea CTCv.3.0 grade ≥2 within 6 months after RT, and cardiac comorbidity as a recorded treatment of a cardiac pathology at a cardiology department. Univariate and multivariate analyses, as well as external validation, were performed. The model-performance measure was the area under the receiver operating characteristic curve (AUC).
  
  
  RESULTS
  Prior to RT, 75/259 (28.9%) patients had cardiac comorbidity, 44% of whom (33/75) developed RILT. The odds ratio of developing RILT for patients with cardiac comorbidity was 2.58 (p<0.01). The cross-validated AUC of a model with cardiac comorbidity, tumor location, forced expiratory volume in 1s, sequential chemotherapy and pretreatment dyspnea score was 0.72 (p<0.001) on the training set, and 0.67 (p<0.001) on the validation set.
  
  
  CONCLUSIONS
  Cardiac comorbidity is an important risk factor for developing RILT after definite radio(chemo)therapy of lung cancer patients.
authors.affiliation: Department of Radiation Oncology (Maastro Clinic), GROW - School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, The Netherlands. Electronic address: georgi.nalbantov@maastro.nl.
authors.forename: Georgi
authors.initials: G
authors.lastname: Nalbantov
authors.forename: Bas
authors.initials: B
authors.lastname: Kietselaer
authors.forename: Katrien
authors.initials: K
authors.lastname: Vandecasteele
authors.forename: Cary
authors.initials: C
authors.lastname: Oberije
authors.forename: Maaike
authors.initials: M
authors.lastname: Berbee
authors.forename: Esther
authors.initials: E
authors.lastname: Troost
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Dingemans
authors.forename: Angela
authors.initials: A
authors.lastname: van Baardwijk
authors.forename: Kim
authors.initials: K
authors.lastname: Smits
authors.forename: André
authors.initials: A
authors.lastname: Dekker
authors.forename: Johan
authors.initials: J
authors.lastname: Bussink
authors.forename: Dirk
authors.initials: D
authors.lastname: De Ruysscher
authors.forename: Yolande
authors.initials: Y
authors.lastname: Lievens
authors.forename: Philippe
authors.initials: P
authors.lastname: Lambin
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D015897:Comorbidity; D005260:Female; D006331:Heart Diseases / Q000150:complications*; D006801:Humans; D008168:Lung / Q000528:radiation effects*; D008175:Lung Neoplasms / Q000532:radiotherapy*; D008297:Male; D011829:Radiation Dosage; D011878:Radiotherapy / Q000009:adverse effects; D012189:Retrospective Studies; D012307:Risk Factors; D012907:Smoking
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors
keywords: Cardiac comorbidity; Dyspnea; Lung cancer; Radiation-induced lung toxicity; Radiotherapy