Y.A. Abuodeh: None. C. Hogue: None. D.G. Stallworth: None. A.O. Naghavi: None. S. Kim: None. ... and none of these series account for the above factors.
Volume 96 Number 2S Supplement 2016 Conclusion: In our institutional analysis of patients treated with SRS and anti-PD-1 therapies, ipilimumab, vemurafenib, or conventional chemotherapy, we note significant differences in distant BM control as well as OS. Prospective evaluation of the potential synergistic effect between antiPD-1 therapies and SRS in the management of brain metastases is warranted. Author Disclosure: K.A. Ahmed: None. Y.A. Abuodeh: None. C. Hogue: None. D.G. Stallworth: None. A.O. Naghavi: None. S. Kim: None. S. Sarangkasiri: None. P.A. Johnstone: None. H. Yu: None. N.I. Khushalani: None. A.B. Etame: None. L.B. Harrison: None. J.J. Caudell: None.
131 Increased Risk of Radiation Necrosis Following BRAF inhibitor therapy and Stereotactic Radiosurgery (SRS) M. Chowdhary,1,2 K. Patel,1,2 J. Switchenko,1,3 D.H. Lawson,1,4 H. Danish,1,2 R.S. Prabhu,5 and M.K. Khan2; 1Emory University School of Medicine, Atlanta, GA, 2Department of Radiation Oncology, Winship Cancer Institute at Emory University, Atlanta, GA, 3Department of Biostatistics and Bioinformatics, Winship Cancer Institute, Emory University, Atlanta, GA, 4Department of Hematology and Medical Oncology, Winship Cancer Institute at Emory University, Atlanta, GA, 5 Levine Cancer Institute: Carolinas HealthCare System, Charlotte, NC Purpose/Objective(s): Melanoma is an aggressive malignancy with an unfortunate predilection for spreading to the brain. Although BRAF inhibitors (BRAFi) have demonstrated intracranial efficacy, recent studies suggest increased toxicity with radiation therapy. Consequently, the 2015 National Comprehensive Cancer Network (NCCN) guidelines raise caution on the combination of BRAFi and radiotherapy. We investigate outcomes and toxicities of SRS and BRAFi compared with SRS alone for patients with melanoma brain metastases (MBM). Materials/Methods: We retrospectively reviewed records of patients who underwent SRS for MBM at our institution from 2005-2013, excluding patients with prior WBRT. Overall survival (OS) and intracranial outcomes were calculated using the Kaplan-Meier method and cumulative incidence with competing risk for death, respectively. Results: Eighty-seven patients with 157 MBM received SRS. Of these, 15 (17.2%) patients with 32 (21.4%) MBM received BRAFi therapy either prior to, concurrent with, or post SRS. Baseline patient characteristics were well balanced, with the only differences between cohorts being prior chemotherapy (0% vs. 29%, P Z 0.017), later year of diagnosis (39% vs. 93%, P < 0.001) and type of next systemic therapy (P < 0.001) in the BRAFi group. Radiation characteristics, including dose per fraction, total dose, GTV volume, and prescription isodose were similar between the groups. Median imaging follow-up was 5.9 (0.4-152.3) and 13.5 (1-39.6) months for the SRS alone and SRS and BRAFi cohorts, respectively. Results are in Table 1: OS at 6 (72.8% vs. 78.6%) and 12 months (40.4% vs. 64.3%) was not statistically different between the SRS alone and SRS and BRAFi groups, respectively (P Z 0.20). 1-year local failure (3.3% vs. 9.6%, P Z 0.423) and distant brain failure (63.9% vs. 65.1%, P Z 0.450) rates were also similar. Twenty-seven (17.2%) out of 157 total lesions demonstrated radiographic radiation necrosis (RN). 1-year rates of RN, measured at the lesion-level, were higher in the BRAFi group: 22.2% vs. 11.0%, P
