Response of treatment-naive brain metastases to stereotactic radiosurgery
Chibawanye Ene, Christina Abi Faraj, Thomas H. Beckham, Jeffrey S. Weinberg, Clark R. Andersen, Ali S. Haider, Ganesh Rao, Sherise D. Ferguson, Christopher A. Alvarez-Brenkenridge, Betty Y.S. Kim, Amy B. Heimberger, Ian E. McCutcheon, Sujit S. Prabhu, C. Wang, Amol J. Ghia, Susan L. McGovern, Caroline Chung, Mary Frances McAleer, Martin C. Tom, Subha Perni, Todd A. Swanson, D.N. Yeboa, Tina M. Briere, Jason T. Huse, Gregory N. Fuller, Frederick F. Lang, Jing Li, Dima Suki, Raymond E. Sawaya
Abstract
With improvements in survival for patients with metastatic cancer, long-term local control of brain metastases has become an increasingly important clinical priority. While consensus guidelines recommend surgery followed by stereotactic radiosurgery (SRS) for lesions >3 cm, smaller lesions (≤3 cm) treated with SRS alone elicit variable responses. To determine factors influencing this variable response to SRS, we analyzed outcomes of brain metastases ≤3 cm diameter in patients with no prior systemic therapy treated with frame-based single-fraction SRS. Following SRS, 259 out of 1733 (15%) treated lesions demonstrated MRI findings concerning for local treatment failure (LTF), of which 202 /1733 (12%) demonstrated LTF and 54/1733 (3%) had an adverse radiation effect. Multivariate analysis demonstrated tumor size (>1.5 cm) and melanoma histology were associated with higher LTF rates. Our results demonstrate that brain metastases ≤3 cm are not uniformly responsive to SRS and suggest that prospective studies to evaluate the effect of SRS alone or in combination with surgery on brain metastases ≤3 cm matched by tumor size and histology are warranted. These studies will help establish multi-disciplinary treatment guidelines that improve local control while minimizing radiation necrosis during treatment of brain metastasis ≤3 cm.