Risk factors for computed tomography grade of radiation-induced lung injury in lung cancer treated with three-dimensional conformal radiotherapy

Abstract

Objective To analyze the clinical and dosimetric risk factors for computed tomography (CT) grade of radiation-induced lung injury in lung cancer treated with three-dimensional conformal radiotherapy (3DCRT).Methods Eighty-nine lung cancer patients treated with 3DCRT were enrolled and CT scan images in more than 6 months were retrospectively analyzed.Clinical and dosimetric parameters were reviewed.Radiation-induced lung injuries were classified into 5 grades on CT images.Grade 3 or worse were considered clinically significant.Statistical software SPSS IS.0 was used to analyze the clinical and dosimetric risk factors that influenced the CT grade of radiation-induced lung injury.Results Eight of 89 patients (9.0%) developed grade 0 of radiation-induced lung injury,13 developed grade 1 (14.6%) ,24 developed grade 2 (27.0%) ,23 developed grade 3 (25.8%) and 21 developed grade 4 (23.6%).Univariable analysis showed that concurrent chemotherapy (CCT),GTV margin,involved ipsilateral lung mean lung dose(IMLD) ,the percent of involved ipsilateral lung receiving over IS,20,25 ,30,35 ,40 and 45 Gy (V_(15),V_(20) ,V_(25),V_(30) ,V_(35),V_(40) ,V_(45) were significantly associated with over grade 3 of radiation-induced lung injury .On multivariate logistic regression analysis,CCT,GTV margin and V_(20) of ipsilateral lung emerged as statistically significant risk factors of over grade 3 radiation-induced lung injuries CT images.Conclusions CCT,GTV margin and V_(20) of ipsilateral lung might be clinical and dosimetric risk factors associated with the severe CT grade of radiation-induced lung injury for lung cancer treated with 3DCRT. Key words: Lung cancer; Three-dimensional conformal radiotherapy; Radiation-induced lung injury; CT grade