Clinical and dosimetric factors associated with radiation-induced lung damage in patients with non-small cell lung cancer treated with three-dimentional conformai radiotherapy

Abstract

Objective To investigate the factors associated with radiation-induced lung damage in non-small cell lung cancer (NSCLC) treated with radical three-dimensional conformal radiotherapy (3DCRT). Methods Eighty-six patients with NSCLC were treated by radical 3DCRT (total dose 60-66 Gy, 1.8-2.0 Gy/f, 5 d/w). Several clinical and dosimetric factors were analyzed retrospectively, inclu-ding sex, age, smoking history, heart disease history, pulmonary function, tumor location, clinical stage,pathological diagnosis, chemotherapy, total dose, numbers of fields, mean lung dose (MLD), V5, V10,V15, V20, V25, V30, V35, V40, V45, V50, V55, V60 and V65. Radiation-induced lung damage was graded ac-cording to the Common Terminology Criteria for Adverse Events version 3.0. Univariate and multivariate an-alyses were performed to identify the predictive factors. Results The median follow-up was 12 months (range, 1-36 months). The incidence of≥ grade 3 radiation-induced lung damage was 13.9%. In univari-ate analysis, V5, V10,V15, V20, V25, V30, V35and MLD were all significantly associated with radiation-induced lung damage, while the clinical factors, total dose, numbers of fields, V40, V45, V50, V55, V60and V65 were not. In Logistic regression analysis, Vs was the only factor significantly associated with radiation-induced lung damage (X2 =5.15,P=0.023). The incidence of ≥ grade 3 radiation-induced lung damage in the group with V5≤45% and V5 > 45% were 2.3% and 26.2%, respectively (X2 = 10.24, P = 0.001). Conclu-sions The lung damage may dependent on the irradiated volume more than the radiation dose. A number of doaimetric factors are significantly associated with radiation-induced lung damage. However , V5 should be considered in radical 3DCRT for NSCLC patients to reduce the incidence of radiation-induced lung damage. Key words: Lung neoplasms/radiotherapy; Radiotherapy,three-dimensional conformal; Radia-tion-induced lung injury; Factor analysis