Dose-response for stereotactic body radiotherapy in early-stage non-small-cell lung cancer

Purpose: To compare the efficacy of three lung stereotactic body radiotherapy (SBRT) regimens in a large institutional cohort. Methods:Between2004and2009,130patientsunderwentdefinitivelungcancerSBRTtoasinglelesionattheMallinckrodt Institute of Radiology. We delivered 18 Gy � 3 fractions for peripheral tumors (n = 111) and either 9 Gy � 5 fractions (n =8 ) or 10 Gy� 5 fractions (n = 11) for tumors that were central or near critical structures. Univariate and multivariate analysis of prognostic factors was performed using the Cox proportional hazard model. Results: Median follow-up was 11, 16, and 13 months for the 9 Gy � 5, 10 Gy � 5, and 18 Gy � 3 groups, respectively. Local control statistics for Years 1 and 2 were, respectively, 75% and 50% for 9 Gy � 5, 100% and 100% for 10 Gy � 5, and 99% and 91% for 18 Gy � 3. Median overall survival was 14 months, not reached, and 34 months for the 9 Gy � 5, 10 Gy � 5, and 18 Gy � 3 treatments, respectively. No difference in local control or overall survival was found between the 10 Gy � 5 and 18 Gy � 3 groups on log–rank test, but both groups had improved local control and overall survival compared with 9 Gy � 5. Treatment with 9 Gy � 5 was the only independent prognostic factor for reduced local control on multivariate analysis, and increasing age, increasing tumor volume, and poor performance status predicted independently for reduced overall survival. Conclusion: Treatment regimens of 10 Gy � 5 and 18 Gy � 3 seem to be efficacious for lung cancer SBRT and provide superior local control and overall survival compared with 9 Gy � 5. 2011 Elsevier Inc. Lung, Cancer, NSCLC, SBRT, Stereotactic.