Analysis of four sorts of clinical factors associated with radiation-induced lung injury in patients with NSCLC after 3D-CRT

Abstract

7552 Background: There are different clinical factors associated with radiation-induced lung injury in patients with non-small cell lung cancer (NSCLC) after three-dimensional conformal radiation therapy (3D-CRT) that have been studied, whereas their value are not same. According to their source, the factors can be sorted to four types. Methods: 119 NSCLC patients treated with 3D-CRT during 2003–2005 were retrospectively reviewed. They were divided into two arms according to whether grade >2 radiation- induced lung injury named by RTOG 3.0 were observed. The clinical parameters related to radiation-induced lung injury were divided into four sorts: general state of health and systematic sickness (gender, age, KPS, COPD, heart disease, diabetes), tumor-related factors (location, stage, volume), radiotherapy-related factors (dose, fraction per day, target margin, dosimetric parameters), other treatment factors (chemotherapy timing and agents). Univariate and multivariate analyses of the relation between clinical parameters and radiation pneumonitis were performed. Results: Occurrence of grade >2 radiation-induced lung injury was observed in 17/119 patients. In univariate analyses, GTV (p=0.009), ipsilateral mean lung dose (MLD)(p=0.017), ipsilateral lung V20 (p=0.036)and total lung MLD (p=0.034) were associated with radiation-induced lung injury. In multivariate analysis, ipsilateral lung MLD was the only independent factor associated with radiation-induced lung injury (p=0.019). A significant correlation was also observed between the three volumetric parameters (p≤0.001). Conclusions: Ipsilateral lung MLD was the only independent factor associated with grade >2 radiation-induced lung injury in our study, so that it should be included as a dose constraint factor for 3D-CRT of NSCLC. No significant financial relationships to disclose.