Factors affecting the local control of stereotactic body radiotherapy for lung tumors including primary lung cancer and metastatic lung tumors

Abstract

To identify factors affecting local control of stereotactic body radiotherapy (SBRT) for lung tumors including primary lung cancer and metastatic lung tumors. Between June 2006 and June 2009, 159 lung tumors in 144 patients (primary lung cancer, 128; metastatic lung tumor, 31) were treated with SBRT with 48-60 Gy (mean 50.1 Gy) in 4-5 fractions. Higher doses were given to larger tumors and metastatic tumors in principle. Assessed factors were age, gender, tumor origin (primary vs. metastatic), histological subtype, tumor size, tumor appearance (solid vs. ground glass opacity), maximum standardized uptake value of positron emission tomography using (18)F-fluoro-2-deoxy-D: -glucose, and SBRT doses. Follow-up time was 1-60 months (median 18 months). The 1-, 2-, and 3-year local failure-free rates of all lesions were 90, 80, and 77 %, respectively. On univariate analysis, metastatic tumors (p < 0.0001), solid tumors (p = 0.0246), and higher SBRT doses (p = 0.0334) were the statistically significant unfavorable factors for local control. On multivariate analysis, only tumor origin was statistically significant (p = 0.0027). The 2-year local failure-free rates of primary lung cancer and metastatic lung tumors were 87 and 50 %, respectively. A metastatic tumor was the only independently significant unfavorable factor for local control after SBRT.