predictive factors of radiation-induced lung toxicity in lung cancer patients: a retrospective study

Background: radiation-induced lung toxicity is an important dose-limiting toxicityin lung cancer radiotherapy, for which there are no generally accepted predictivefactors. this study seeks to identify risk factors associated with the development of severeradiation-induced lung toxicity using clinical and dosimetric parameters.methods: we reviewed the medical records of 54 patients with histologicallyproven stage iii non-small cell lung cancer treated with three dimensional-conformalradiotherapy at alexandria main university hospital between january 2008 anddecember 2011. the original treatment plans for those patients were restored andimported to a treatment planning system. lung dose–volume histograms and variousdosimetric parameters were calculated. univariate and multivariate logistic regressionanalyses were performed.results: the following grades of radiation-induced lung toxicity were observed inpatients - grade 0: 17 (31.5%), grade 1: 5 (9.3%), grade 2: 13 (24.1%), grade 3: 15(27.8%), and grade 5: 4 (7.4%). a total of 19 (35.2%) patients developed grade ?3 andwere considered to have an event. univariate analysis showed that age, presence ofchronic obstructive pulmonary disease and location of the primary tumor had significantassociations with severe radiation-induced lung toxicity. other dosimetric variables suchas tumor side, histology, forced expiratory volume in 1 s, smoking, and gender showedno significant correlations with severe radiation-induced lung toxicity. multivariateanalysis showed that the presence of chronic obstructive pulmonary disease (p=0.001)and location of the primary tumor (p=0.010) were the only predictive factors forsevere radiation-induced lung toxicity.conclusion: this study demonstrates that patients with chronic obstructivepulmonary disease and lower lung lobe tumors have a high risk of severe radiationinducedlung toxicity when treated with combined chemoradiotherapy. these easilyobtained clinical factors should be considered when calculating the risk for radiationinducedlung toxicity.