Background: Stereotactic body radiation therapy [SBRT] is a treatment option in several malignant diseases.

Objective: To assess the treatment outcome of SBRT in lung tumors in terms of response rates, local control, overall survival, and prognostic factors associated with response rate.

Materials and Methods: Twenty-one patients (32 lesions) with early-stage non-small cell lung cancer [NSCLC] or oligometastatic lung disease who received SBRT between January 20l2 and March 20l6 were included in this retrospective study. Overall survival and local control rate were calculated using the Kaplan-Meier method. Prognostic factors for response rate, including equivalent sphere
diameter, tumor volume, biologically effective dose, and tumor type and location, were analyzed using Fisher's exact test.

Results: Median follow-up was l6.l months; 59.4% of patients had complete response, 28.l% had partial response, and only 3.l% had progressive disease. Local control at l, 2, and 3 years was 94.l%, 87.4%, and 87.4%, respectively. Overall survival at l, 3, and 5 years was 90.2%, 90.2%, and 67.7%, respectively. In univariate analysis for response rate, tumor type (primary or metastatic) was the only significant factor.

Conclusion: SBRT in early-stage NSCLC and oligometastatic lung tumors produces promising outcomes in terms of response rate and local disease control.

Keywords: Stereotactic body radiation therapy [SBRT]; Treatment outcome; Early-stage NSCLCs; Oligometastatic diseases